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  • N2 CMS SlidingCurtain control is not visible

    - by Carl Raymond
    I just set up a new N2 site by starting with the MVC 2 Web Application template in Visual Studio, then following the directions in N2 CMS Developer Documentation in the section Integrating with Existing ASP.NET MVC Application. I have the basic site running now, but with one problem: the sliding curtain widget that holds the administrative controls is not visible in the upper right corner (when logged in, of course). I can make it visible the hard way by using Firebug to locate it in the DOM, and then disabling a couple of the CSS positioning elements. Once I do that, it seems to work normally. After I open it that way, I can click the various controls, or close it up (and I see the animation). But then it's off screen again. My master page has the sliding curtain just inside the <body> tag: <body> <n2:SlidingCurtain runat="server"> <n2:ControlPanel runat="server" /> </n2:SlidingCurtain> ... The site.css file generated in the base MVC site doesn't seem to do any positioning that would affect this. Firebug shows that right after by <body> tag, I have this: <div class="sc" id="SC" style="top: -2px; left: -574px;"><div class="scContent"> .... The style for <div class="sc" ...> is element.style { left:-574px; top:-2px; } .sc { background:#FFFFFF none repeat-x scroll 0 0; border-color:#CCCCBB; border-style:none solid solid none; border-width:1px; left:-200px; position:fixed; top:-200px; z-index:990; } If I disable both top: and both left: rules, the widget appears.

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  • Nhibernate one-to-many with table per subclass

    - by Wayne
    I am customizing N2CMS's database structure, and met with an issue. The two classes are listed below. public class Customer : ContentItem { public IList<License> Licenses { get; set; } } public class License : ContentItem { public Customer Customer { get; set; } } The nhibernate mapping are as follows. <class name="N2.ContentItem,N2" table="n2item"> <cache usage="read-write" /> <id name="ID" column="ID" type="Int32" unsaved-value="0" access="property"> <generator class="native" /> </id> <discriminator column="Type" type="String" /> </class> <subclass name="My.Customer,My" extends="N2.ContentItem,N2" discriminator-value="Customer"> <join table="Customer"> <key column="ItemID" /> <bag name="Licenses" generic="true" inverse="true"> <key column="CustomerID" /> <one-to-many class="My.License,My"/> </bag> </join> </subclass> <subclass name="My.License,My" extends="N2.ContentItem,N2" discriminator-value="License"> <join table="License" fetch="select"> <key column="ItemID" /> <many-to-one name="Customer" column="CustomerID" class="My.Customer,My" not-null="false" /> </join> </subclass> Then, when get an instance of Customer, the customer.Licenses is always empty, but actually there are licenses in the database for the customer. When I check the nhibernate log file, I find that the SQL query is like: SELECT licenses0_.CustomerID as CustomerID1_, licenses0_.ID as ID1_, licenses0_.ID as ID2_0_, licenses0_1_.CustomerID as CustomerID7_0_, FROM n2item licenses0_ inner join License licenses0_1_ on licenses0_.ID = licenses0_1_.ItemID WHERE licenses0_.CustomerID = 12 /* @p0 */ It seems that nhibernate believes that the CustomerID is in the 'n2item' table. I don't know why, but to make it work, I think the SQL should be something like this. SELECT licenses0_.ID as ID1_, licenses0_.ID as ID2_0_, licenses0_1_.CustomerID as CustomerID7_0_, FROM n2item licenses0_ inner join License licenses0_1_ on licenses0_.ID = licenses0_1_.ItemID WHERE licenses0_1_.CustomerID = 12 /* @p0 */ Could any one point out what's wrong with my mappings? And how can I get the correct licenses of one customer? Thanks in advance.

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  • Cannot add namespace prefix to children using XSL

    - by Erdal
    I checked many answers here and I think I am almost there. One thing that is bugging me (and for some reason my peer needs it) follows: I have the following input XML: <?xml version="1.0" encoding="utf-8"?> <MyRoot> <MyRequest CompletionCode="0" CustomerID="9999999999"/> <List TotalList="1"> <Order CustomerID="999999999" OrderNo="0000000001" Status="Shipped"> <BillToAddress ZipCode="22221"/> <ShipToAddress ZipCode="22222"/> <Totals Tax="0.50" SubTotal="10.00" Shipping="4.95"/> </Order> </List> <Errors/> </MyRoot> I was asked to produce this: <ns:MyNewRoot xmlns:ns="http://schemas.foo.com/response" xmlns:N1="http://schemas.foo.com/request" xmlns:N2="http://schemas.foo.com/details"> <N1:MyRequest CompletionCode="0" CustomerID="9999999999"/> <ns:List TotalList="1"> <N2:Order CustomerID="999999999" Level="Preferred" Status="Shipped"> <N2:BillToAddress ZipCode="22221"/> <N2:ShipToAddress ZipCode="22222"/> <N2:Totals Tax="0.50" SubTotal="10.00" Shipping="4.95"/> </N2:Order> </ns:List> <ns:Errors/> </ns:MyNewRoot> Note the children of the N2:Order also needs N2: prefix as well as the ns: prefix for the rest of the elements. I use the XSL transformation below: <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:output omit-xml-declaration="yes" indent="yes"/> <xsl:template match="@* | node()"> <xsl:copy> <xsl:apply-templates select="@* | node()"/> </xsl:copy> </xsl:template> <xsl:template match="/MyRoot"> <MyNewRoot xmlns="http://schemas.foo.com/response" xmlns:N1="http://schemas.foo.com/request" xmlns:N2="http://schemas.foo.com/details"> <xsl:apply-templates/> </MyNewRoot> </xsl:template> <xsl:template match="/MyRoot/MyRequest"> <xsl:element name="N1:{name()}" namespace="http://schemas.foo.com/request"> <xsl:copy-of select="namespace::*"/> <xsl:apply-templates select="@* | node()"/> </xsl:element> </xsl:template> <xsl:template match="/MyRoot/List/Order"> <xsl:element name="N2:{name()}" namespace="http://schemas.foo.com/details"> <xsl:copy-of select="namespace::*"/> <xsl:apply-templates select="@* | node()"/> </xsl:element> </xsl:template> </xsl:stylesheet> This one doesn't process the ns (I couldn't figure this out). When I process thru the above the XSL transformation with AltovaXML I end up with below: <MyNewRoot xmlns="http://schemas.foo.com/response" xmlns:N1="http://schemas.foo.com/request" xmlns:N2="http://schemas.foo.com/details"> <N1:MyRequest CompletionCode="0" CustomerID="9999999999"/> <List xmlns="" TotalList="1"> <N2:Order CustomerID="999999999" Level="Preferred" Status="Shipped"> <BillToAddress ZipCode="22221"/> <ShipToAddress ZipCode="22222"/> <Totals Tax="0.50" SubTotal="10.00" Shipping="4.95"/> </N2:Order> </List> <Errors/> </MyNewRoot> Note that N2: prefix for the children of Order is not there after the XSL transformation. Also additional xmlns="" in the Order header (for some reason). I couldn't figure out putting the ns: prefix for the rest of the elements (like Errors and List). First of all, why would I need to put the prefix for the children if the parent already has it. Doesn't the parent namespace dictate the children nodes/attribute namespaces? Secondly, I want to add the prefixes in the above XML as expected, how can I do that with XSL?

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  • Uncompiled WCF on IIS7: The type could not be found

    - by Jimmy
    Hello, I've been trying to follow this tutorial for deploying a WCF sample to IIS . I can't get it to work. This is a hosted site, but I do have IIS Manager access to the server. However, in step 2 of the tutorial, I can't "create a new IIS application that is physically located in this application directory". I can't seem to find a menu item, context menu item, or what not to create a new application. I've been right-clicking everywhere like crazy and still can't figure out how to create a new app. I suppose that's probably the root issue, but I tried a few other things (described below) just in case that actually is not the issue. This is "deployed" at http://test.com.cws1.my-hosting-panel.com/IISHostedCalcService/Service.svc . The error says: The type 'Microsoft.ServiceModel.Samples.CalculatorService', provided as the Service attribute value in the ServiceHost directive, or provided in the configuration element system.serviceModel/serviceHostingEnvironment/serviceActivations could not be found. I also tried to create a virtual dir (IISHostedCalc) in dotnetpanel that points to IISHostedCalcService . When I navigate to http://test.com.cws1.my-hosting-panel.com/IISHostedCalc/Service.svc , then there is a different error: This collection already contains an address with scheme http. There can be at most one address per scheme in this collection. As per the tutorial, there was no compiling involved; I just dropped the files on the server as follow inside the folder IISHostedCalcService: service.svc Web.config Service.cs service.svc contains: <%@ServiceHost language=c# Debug="true" Service="Microsoft.ServiceModel.Samples.CalculatorService"%> (I tried with quotes around the c# attribute, as this looks a little strange without quotes, but it made no difference) Web.config contains: <?xml version="1.0" encoding="utf-8" ?> <configuration> <system.serviceModel> <services> <service name="Microsoft.ServiceModel.Samples.CalculatorService"> <!-- This endpoint is exposed at the base address provided by host: http://localhost/servicemodelsamples/service.svc --> <endpoint address="" binding="wsHttpBinding" contract="Microsoft.ServiceModel.Samples.ICalculator" /> <!-- The mex endpoint is explosed at http://localhost/servicemodelsamples/service.svc/mex --> <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" /> </service> </services> </system.serviceModel> <system.web> <customErrors mode="Off"/> </system.web> </configuration> Service.cs contains: using System; using System.ServiceModel; namespace Microsoft.ServiceModel.Samples { [ServiceContract] public interface ICalculator { [OperationContract] double Add(double n1, double n2); [OperationContract] double Subtract(double n1, double n2); [OperationContract] double Multiply(double n1, double n2); [OperationContract] double Divide(double n1, double n2); } public class CalculatorService : ICalculator { public double Add(double n1, double n2) { return n1 + n2; } public double Subtract(double n1, double n2) { return n1 - n2; } public double Multiply(double n1, double n2) { return n1 * n2; } public double Divide(double n1, double n2) { return n1 / n2; } } }

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  • Deploying WCF Tutorial App on IIS7: "The type could not be found"

    - by Jimmy
    Hello, I've been trying to follow this tutorial for deploying a WCF sample to IIS . I can't get it to work. This is a hosted site, but I do have IIS Manager access to the server. However, in step 2 of the tutorial, I can't "create a new IIS application that is physically located in this application directory". I can't seem to find a menu item, context menu item, or what not to create a new application. I've been right-clicking everywhere like crazy and still can't figure out how to create a new app. I suppose that's probably the root issue, but I tried a few other things (described below) just in case that actually is not the issue. Here is a picture of what I see in IIS Manager, in case my words don't do it justice: This is "deployed" at http://test.com.cws1.my-hosting-panel.com/IISHostedCalcService/Service.svc . The error says: The type 'Microsoft.ServiceModel.Samples.CalculatorService', provided as the Service attribute value in the ServiceHost directive, or provided in the configuration element system.serviceModel/serviceHostingEnvironment/serviceActivations could not be found. I also tried to create a virtual dir (IISHostedCalc) in dotnetpanel that points to IISHostedCalcService . When I navigate to http://test.com.cws1.my-hosting-panel.com/IISHostedCalc/Service.svc , then there is a different error: This collection already contains an address with scheme http. There can be at most one address per scheme in this collection. Interestingly enough, if I click on View Applications, it seems like the virtual directory is an application (see image below)... although, as per the error message above, it doesn't work. As per the tutorial, there was no compiling involved; I just dropped the files on the server as follow inside the folder IISHostedCalcService: service.svc Web.config <dir: App_Code> Service.cs service.svc contains: <%@ServiceHost language=c# Debug="true" Service="Microsoft.ServiceModel.Samples.CalculatorService"%> (I tried with quotes around the c# attribute, as this looks a little strange without quotes, but it made no difference) Web.config contains: <?xml version="1.0" encoding="utf-8" ?> <configuration> <system.serviceModel> <services> <service name="Microsoft.ServiceModel.Samples.CalculatorService"> <!-- This endpoint is exposed at the base address provided by host: http://localhost/servicemodelsamples/service.svc --> <endpoint address="" binding="wsHttpBinding" contract="Microsoft.ServiceModel.Samples.ICalculator" /> <!-- The mex endpoint is explosed at http://localhost/servicemodelsamples/service.svc/mex --> <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" /> </service> </services> </system.serviceModel> <system.web> <customErrors mode="Off"/> </system.web> </configuration> Service.cs contains: using System; using System.ServiceModel; namespace Microsoft.ServiceModel.Samples { [ServiceContract] public interface ICalculator { [OperationContract] double Add(double n1, double n2); [OperationContract] double Subtract(double n1, double n2); [OperationContract] double Multiply(double n1, double n2); [OperationContract] double Divide(double n1, double n2); } public class CalculatorService : ICalculator { public double Add(double n1, double n2) { return n1 + n2; } public double Subtract(double n1, double n2) { return n1 - n2; } public double Multiply(double n1, double n2) { return n1 * n2; } public double Divide(double n1, double n2) { return n1 / n2; } } }

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  • Recompiling an old fortran 2/4\66 program that was compiled for os\2 need it to run in dos

    - by Mike Hansen
    I am helping an old scientist with some problems and have 1 program that he found and modified about 20 yrs. ago, and runs fine as a 32 bit os\2 executable but i need it to run under dos! I am not a programmer but a good hardware & software man, so I'am pretty stupid about this problem, but here go's I have downloaded 6 different compilers watcom77,silverfrost ftn95,gfortran,2 versions of g77 and f80. Watcom says it is to old of program,find older compiler,silverfrost opens it,debugs, etc. but is changing all the subroutines from "real" to "complex" and vice-vesa,and the g77's seem to install perfectly (library links and etc.) but wont even compile the test.f programs.My problem is 1; to recompile "as is" or "upgrade" the code? PROGRAM xconvlv INTEGER N,N2,M PARAMETER (N=2048,N2=2048,M=128) INTEGER i,isign REAL data(n),respns(m),resp(n),ans(n2),t3(n),DUMMY OPEN(UNIT=1, FILE='C:\QKBAS20\FDATA1.DAT') DO 1 i=1,N READ(1,*) T3(i), data(i), DUMMY continue CLOSE(UNIT-1) do 12 i=1,N respns(i)=data(i) resp(i)=respns(i) continue isign=-1 call convlv(data,N,resp,M,isign,ans) OPEN(UNIT=1,FILE='C:\QKBAS20\FDATA9.DAT') DO 14 i=1,N WRITE(1,*) T3(i), ans(i) continue END SUBROUTINE CONVLV(data,n,respns,m,isign,ans) INTEGER isign,m,n,NMAX REAL data(n),respns(n) COMPLEX ans(n) PARAMETER (NMAX=4096) * uses realft, twofft INTEGER i,no2 COMPLEX fft (NMAX) do 11 i=1, (m-1)/2 respns(n+1-i)=respns(m+1-i) continue do 12 i=(m+3)/2,n-(m-1)/2 respns(i)=0.0 continue call twofft (data,respns,fft,ans,n) no2=n/2 do 13 i=1,no2+1 if (isign.eq.1) then ans(i)=fft(i)*ans(i)/no2 else if (isign.eq.-1) then if (abs(ans(i)) .eq.0.0) pause ans(i)=fft(i)/ans(i)/no2 else pause 'no meaning for isign in convlv' endif continue ans(1)=cmplx(real (ans(1)),real (ans(no2+1))) call realft(ans,n,-1) return END SUBROUTINE realft(data,n,isign) INTEGER isign,n REAL data(n) * uses four1 INTEGER i,i1,i2,i3,i4,n2p3 REAL c1,c2,hli,hir,h2i,h2r,wis,wrs DOUBLE PRECISION theta,wi,wpi,wpr,wr,wtemp theta=3.141592653589793d0/dble(n/2) cl=0.5 if (isign.eq.1) then c2=-0.5 call four1(data,n/2,+1) else c2=0.5 theta=-theta endif (etc.,etc., etc.) SUBROUTINE twofft(data,data2,fft1,fft2,n) INTEGER n REAL data1(n,data2(n) COMPLEX fft1(n), fft2(n) * uses four1 INTEGER j,n2 COMPLEX h1,h2,c1,c2 c1=cmplx(0.5,0.0) c2=cmplx(0.0,-0.5) do 11 j=1,n fft1(j)=cmplx(data1(j),data2(j) continue call four1 (fft1,n,1) fft2(1)=cmplx(aimag(fft1(1)),0.0) fft1(1)=cmplx(real(fft1(1)),0.0) n2=n+2 do 12 j=2,n/2+1 h1=c1*(fft1(j)+conjg(fft1(n2-j))) h2=c2*(fft1(j)-conjg(fft1(n2-j))) fft1(j)=h1 fft1(n2-j)=conjg(h1) fft2(j)=h2 fft2(n2-j)=conjg(h2) continue return END SUBROUTINE four1(data,nn,isign) INTEGER isign,nn REAL data(2*nn) INTEGER i,istep,j,m,mmax,n REAL tempi,tempr DOUBLE PRECISION theta, wi,wpi,wpr,wr,wtemp n=2*nn j=1 do 11 i=1,n,2 if(j.gt.i)then tempr=data(j) tempi=data(j+1) (etc.,etc.,etc.,) continue mmax=istep goto 2 endif return END There are 4 subroutines with this that are about 3 pages of code and whould be much easier to e-mail to someone if their able to help me with this.My e-mail is [email protected] , or if someone could tell me where to get a "working" compiler that could recompile this? THANK-YOU, THANK-YOU,and THANK-YOU for any help with this! The errors Iam getting are; 1.In a call to CONVLV from another procedure,the first argument was of a type REAL(kind=1), it is now a COMPLEX(kind=1) 2.In a call to REALFT from another procedure, ... COMPLEX(kind=1) it is now a REAL(kind=1) 3.In a call to TWOFFT from...COMPLEX(kind-1) it is now a REAL(kind=1) 4.In a previous call to FOUR1, the first argument was of a type REAL(kind=1) it is now a COMPLEX(kind=1).

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  • A tale from a Stalker

    - by Peter Larsson
    Today I thought I should write something about a stalker I've got. Don't get me wrong, I have way more fans than stalkers, but this stalker is particular persistent towards me. It all started when I wrote about Relational Division with Sets late last year(http://weblogs.sqlteam.com/peterl/archive/2010/07/02/Proper-Relational-Division-With-Sets.aspx) and no matter what he tried, he didn't get a better performing query than me. But this I didn't click until later into this conversation. He must have saved himself for 9 months before posting to me again. Well... Some days ago I get an email from someone I thought i didn't know. Here is his first email Hi, I want a proper solution for achievement the result. The solution must be standard query, means no using as any native code like TOP clause, also the query should run in SQL Server 2000 (no CTE use). We have a table with consecutive keys (nbr) that is not exact sequence. We need bringing all values related with nearest key in the current key row. See the DDL: CREATE TABLE Nums(nbr INTEGER NOT NULL PRIMARY KEY, val INTEGER NOT NULL); INSERT INTO Nums(nbr, val) VALUES (1, 0),(5, 7),(9, 4); See the Result: pre_nbr     pre_val     nbr         val         nxt_nbr     nxt_val ----------- ----------- ----------- ----------- ----------- ----------- NULL        NULL        1           0           5           7 1           0           5           7           9           4 5           7           9           4           NULL        NULL The goal is suggesting most elegant solution. I would like see your best solution first, after that I will send my best (if not same with yours)   Notice there is no name, no please or nothing polite asking for my help. So, on the top of my head I sent him two solutions, following the rule "Work on SQL Server 2000 and only standard non-native code".     -- Peso 1 SELECT               pre_nbr,                              (                                                           SELECT               x.val                                                           FROM                dbo.Nums AS x                                                           WHERE              x.nbr = d.pre_nbr                              ) AS pre_val,                              d.nbr,                              d.val,                              d.nxt_nbr,                              (                                                           SELECT               x.val                                                           FROM                dbo.Nums AS x                                                           WHERE              x.nbr = d.nxt_nbr                              ) AS nxt_val FROM                (                                                           SELECT               (                                                                                                                     SELECT               MAX(x.nbr) AS nbr                                                                                                                     FROM                dbo.Nums AS x                                                                                                                     WHERE              x.nbr < n.nbr                                                                                        ) AS pre_nbr,                                                                                        n.nbr,                                                                                        n.val,                                                                                        (                                                                                                                     SELECT               MIN(x.nbr) AS nbr                                                                                                                     FROM                dbo.Nums AS x                                                                                                                     WHERE              x.nbr > n.nbr                                                                                        ) AS nxt_nbr                                                           FROM                dbo.Nums AS n                              ) AS d -- Peso 2 CREATE TABLE #Temp                                                         (                                                                                        ID INT IDENTITY(1, 1) PRIMARY KEY,                                                                                        nbr INT,                                                                                        val INT                                                           )   INSERT                                            #Temp                                                           (                                                                                        nbr,                                                                                        val                                                           ) SELECT                                            nbr,                                                           val FROM                                             dbo.Nums ORDER BY         nbr   SELECT                                            pre.nbr AS pre_nbr,                                                           pre.val AS pre_val,                                                           t.nbr,                                                           t.val,                                                           nxt.nbr AS nxt_nbr,                                                           nxt.val AS nxt_val FROM                                             #Temp AS pre RIGHT JOIN      #Temp AS t ON t.ID = pre.ID + 1 LEFT JOIN         #Temp AS nxt ON nxt.ID = t.ID + 1   DROP TABLE    #Temp Notice there are no indexes on #Temp table yet. And here is where the conversation derailed. First I got this response back Now my solutions: --My 1st Slt SELECT T2.*, T1.*, T3.*   FROM Nums AS T1        LEFT JOIN Nums AS T2          ON T2.nbr = (SELECT MAX(nbr)                         FROM Nums                        WHERE nbr < T1.nbr)        LEFT JOIN Nums AS T3          ON T3.nbr = (SELECT MIN(nbr)                         FROM Nums                        WHERE nbr > T1.nbr); --My 2nd Slt SELECT MAX(CASE WHEN N1.nbr > N2.nbr THEN N2.nbr ELSE NULL END) AS pre_nbr,        (SELECT val FROM Nums WHERE nbr = MAX(CASE WHEN N1.nbr > N2.nbr THEN N2.nbr ELSE NULL END)) AS pre_val,        N1.nbr AS cur_nbr, N1.val AS cur_val,        MIN(CASE WHEN N1.nbr < N2.nbr THEN N2.nbr ELSE NULL END) AS nxt_nbr,        (SELECT val FROM Nums WHERE nbr = MIN(CASE WHEN N1.nbr < N2.nbr THEN N2.nbr ELSE NULL END)) AS nxt_val   FROM Nums AS N1,        Nums AS N2  GROUP BY N1.nbr, N1.val;   /* My 1st Slt Table 'Nums'. Scan count 7, logical reads 14 My 2nd Slt Table 'Nums'. Scan count 4, logical reads 23 Peso 1 Table 'Nums'. Scan count 9, logical reads 28 Peso 2 Table '#Temp'. Scan count 0, logical reads 7 Table 'Nums'. Scan count 1, logical reads 2 Table '#Temp'. Scan count 3, logical reads 16 */  To this, I emailed him back asking for a scalability test What if you try with a Nums table with 100,000 rows? His response to that started to get nasty.  I have to say Peso 2 is not acceptable. As I said before the solution must be standard, ORDER BY is not part of standard SELECT. Try this without ORDER BY:  Truncate Table Nums INSERT INTO Nums (nbr, val) VALUES (1, 0),(9,4), (5, 7)  So now we have new rules. No ORDER BY because it's not standard SQL! Of course I asked him  Why do you have that idea? ORDER BY is not standard? To this, his replies went stranger and stranger Standard Select = Set-based (no any cursor) It’s free to know, just refer to Advanced SQL Programming by Celko or mail to him if you accept comments from him. What the stalker probably doesn't know, is that I and Mr Celko occasionally are involved in some conversation and thus we exchange emails. I don't know if this reference to Mr Celko was made to intimidate me either. So I answered him, still polite, this What do you mean? The SELECT itself has a ”cursor under the hood”. Now the stalker gets rude  But however I mean the solution must no containing any order by, top... No problem, I do not like Peso 2, it’s very non-intelligent and elementary. Yes, Peso 2 is elementary but most performing queries are... And now is the time where I started to feel the stalker really wanted to achieve something else, so I wrote to him So what is your goal? Have a query that performs well, or a query that is super-portable? My Peso 2 outperforms any of your code with a factor of 100 when using more than 100,000 rows. While I awaited his answer, I posted him this query Ok, here is another one -- Peso 3 SELECT             MAX(CASE WHEN d = 1 THEN nbr ELSE NULL END) AS pre_nbr,                    MAX(CASE WHEN d = 1 THEN val ELSE NULL END) AS pre_val,                    MAX(CASE WHEN d = 0 THEN nbr ELSE NULL END) AS nbr,                    MAX(CASE WHEN d = 0 THEN val ELSE NULL END) AS val,                    MAX(CASE WHEN d = -1 THEN nbr ELSE NULL END) AS nxt_nbr,                    MAX(CASE WHEN d = -1 THEN val ELSE NULL END) AS nxt_val FROM               (                              SELECT    nbr,                                        val,                                        ROW_NUMBER() OVER (ORDER BY nbr) AS SeqID                              FROM      dbo.Nums                    ) AS s CROSS JOIN         (                              VALUES    (-1),                                        (0),                                        (1)                    ) AS x(d) GROUP BY           SeqID + x.d HAVING             COUNT(*) > 1 And here is the stats Table 'Nums'. Scan count 1, logical reads 2, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. It beats the hell out of your queries…. Now I finally got a response from my stalker and now I also clicked who he was. This is his reponse Why you post my original method with a bit change under you name? I do not like it. See: http://www.sqlservercentral.com/Forums/Topic468501-362-14.aspx ;WITH C AS ( SELECT seq_nbr, k,        DENSE_RANK() OVER(ORDER BY seq_nbr ASC) + k AS grp_fct   FROM [Sample]         CROSS JOIN         (VALUES (-1), (0), (1)         ) AS D(k) ) SELECT MIN(seq_nbr) AS pre_value,        MAX(CASE WHEN k = 0 THEN seq_nbr END) AS current_value,        MAX(seq_nbr) AS next_value   FROM C GROUP BY grp_fct HAVING min(seq_nbr) < max(seq_nbr); These posts: Posted Tuesday, April 12, 2011 10:04 AM Posted Tuesday, April 12, 2011 1:22 PM Why post a solution where will not work in SQL Server 2000? Wait a minute! His own solution is using both a CTE and a ranking function so his query will not work on SQL Server 2000! Bummer... The reference to "Me not like" are my exact words in a previous topic on SQLTeam.com and when I remembered the phrasing, I also knew who he was. See this topic http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=159262 where he writes a query and posts it under my name, as if I wrote it. So I answered him this (less polite). Like I keep track of all topics in the whole world… J So you think you are the only one coming up with this idea? Besides, “M S solution” doesn’t work.   This is the result I get pre_value        current_value                             next_value 1                           1                           5 1                           5                           9 5                           9                           9   And I did nothing like you did here, where you posted a solution which you “thought” I should write http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=159262 So why are you yourself using ranking function when this was not allowed per your original email, and no cte? You use CTE in your link above, which do not work in SQL Server 2000. All this makes no sense to me, other than you are trying your best to once in a lifetime create a better performing query than me? After a few hours I get this email back. I don't fully understand it, but it's probably a language barrier. >>Like I keep track of all topics in the whole world… J So you think you are the only one coming up with this idea?<< You right, but do not think you are the first creator of this.   >>Besides, “M S Solution” doesn’t work. This is the result I get <<   Why you get so unimportant mistake? See this post to correct it: Posted 4/12/2011 8:22:23 PM >> So why are you yourself using ranking function when this was not allowed per your original email, and no cte? You use CTE in your link above, which do not work in SQL Server 2000. <<  Again, why you get some unimportant incompatibility? You offer that solution for current goals not me  >> All this makes no sense to me, other than you are trying your best to once in a lifetime create a better performing query than me? <<  No, I only wanted to know who you will solve it. Now I know you do not have a special solution. No problem. No problem for me either. So I just answered him I am not the first, and you are not the first to come up with this idea. So what is your problem? I am pretty sure other people have come up with the same idea before us. I used this technique all the way back to 2007, see http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=93911 Let's see if he returns...  He did! >> So what is your problem? << Nothing Thanks for all replies; maybe we have some competitions in future, maybe. Also I like you but you do not attend it. Your behavior with me is not friendly. Not any meeting… Regards //Peso

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  • How to do a Postgresql subquery in select clause with join in from clause like SQL Server?

    - by Ricardo
    I am trying to write the following query on postgresql: select name, author_id, count(1), (select count(1) from names as n2 where n2.id = n1.id and t2.author_id = t1.author_id ) from names as n1 group by name, author_id This would certainly work on Microsft SQL Server but it does not at all on postegresql. I read its documentation a bit and it seems I could rewrite it as: select name, author_id, count(1), total from names as n1, (select count(1) as total from names as n2 where n2.id = n1.id and n2.author_id = t1.author_id ) as total group by name, author_id But that returns the following error on postegresql: "subquery in FROM cannot refer to other relations of same query level". So I'm stuck. Does anyone know how I can achieve that? Thanks

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  • Test, if object was deleted

    - by justik
    Look to the following code, please: class Node { private: double x, y; public: Node (double xx, double yy): x(xx), y(yy){} }; int main() { Node *n1 = new Node(1,1); Node *n2 = n1; delete n2; n2 = NULL; if (n1 != NULL) //Bad test { delete n1; //throw an exception } } There are two pointers n1, n2 pointed to the same object. I would like to detect whether n2 was deleted using n1 pointer test. But this test results in exception. Is there any way how to determine whether the object was deleted (or was not deleted) using n1 pointer ? Thanks for your help.

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  • LINQ Expression - Dynamic From & Where Clause

    - by chillydk147
    I have the following list of integers that I need to extract varying lists of integers containing numbers from say 2-4 numbers in count. The code below will extract lists with only 2 numbers. var numList = new List<int> { 5, 20, 1, 7, 19, 3, 15, 60, 3, 21, 57, 9 }; var selectedNums = (from n1 in numList from n2 in numList where (n1 > 10) && (n2 > 10) select new { n1, n2 }).ToList(); Is there any way to build up this Linq expression dynamically so that if I wanted lists of 3 numbers it would be compiled as below, this would save me having to package the similar expression inside a different method. var selectedNums = (from n1 in numList from n2 in numList from n3 in numList where (n1 > 10) && (n2 > 10) && (n3 > 10) select new { n1, n2, n3 }).ToList();

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  • Beginner having difficulty with SQL query

    - by Vulcanizer
    Hi, I've been studying SQL for 2 weeks now and I'm preparing for an SQL test. Anyway I'm trying to do this question: For the table: 1 create table data { 2 id int, 3 n1 int not null, 4 n2 int not null, 5 n3 int not null, 6 n4 int not null, 7 primary key (id) 8 } I need to return the relation with tuples (n1, n2, n3) where all the corresponding values for n4 are 0. The problem asks me to solve it WITHOUT using subqueries(nested selects/views) It also gives me an example table and the expected output from my query: 01 insert into data (id, n1, n2, n3, n4) 02 values (1, 2,4,7,0), 03 (2, 2,4,7,0), 04 (3, 3,6,9,8), 05 (4, 1,1,2,1), 06 (5, 1,1,2,0), 07 (6, 1,1,2,0), 08 (7, 5,3,8,0), 09 (8, 5,3,8,0), 10 (9, 5,3,8,0); expects (2,4,7) (5,3,8) and not (1,1,2) since that has a 1 in n4 in one of the cases. The best I could come up with was: 1 SELECT DISTINCT n1, n2, n3 2 FROM data a, data b 3 WHERE a.ID <> b.ID 4 AND a.n1 = b.n1 5 AND a.n2 = b.n2 6 AND a.n3 = b.n3 7 AND a.n4 = b.n4 8 AND a.n4 = 0 but I found out that also prints (1,1,2) since in the example (1,1,2,0) happens twice from IDs 5 and 6. Any suggestions would be really appreciated.

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  • Bidirectional FIFO

    - by nunos
    I would like to implement a bidirectional fifo. The code below is functioning but it is not using bidirectional fifo. I have searched all over the internet, but haven't found any good example... How can I do that? Thanks, WRITER.c: #include <stdio.h> #include <unistd.h> #include <string.h> #include <sys/types.h> #include <sys/wait.h> #include <fcntl.h> #define MAXLINE 4096 #define READ 0 #define WRITE 1 int main (int argc, char** argv) { int a, b, fd; do { fd=open("/tmp/myfifo",O_WRONLY); if (fd==-1) sleep(1); } while (fd==-1); while (1) { scanf("%d", &a); scanf("%d", &b); write(fd,&a,sizeof(int)); write(fd,&b,sizeof(int)); if (a == 0 && b == 0) { break; } } close(fd); return 0; } READER.c: #include <stdio.h> #include <unistd.h> #include <string.h> #include <sys/types.h> #include <sys/wait.h> #include <fcntl.h> #include <sys/stat.h> #define MAXLINE 4096 #define READ 0 #define WRITE 1 int main(void) { int n1, n2; int fd; mkfifo("/tmp/myfifo",0660); fd=open("/tmp/myfifo",O_RDONLY); while(read(fd, &n1, sizeof(int) )) { read(fd, &n2, sizeof(int)); if (n1 == 0 && n2 == 0) { break; } printf("soma: %d\n",n1+n2); printf("diferenca: %d\n", n1-n2); printf("divisao: %f\n", n1/(double)n2); printf("multiplicacao: %d\n", n1*n2); } close(fd); return 0; }

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  • Port forwarding (portmap) works only locally

    - by Tag Wint
    There are four hosts hostA winXP hostB Win2003 hostC Linux RHEL hostD Linux RHEL hostA cannot connect to C and D directly, but B can hostA connects to hostB using VPN hostB and hostC belong to the same subnet1 hostD is in subnet2 From hostA I need to connect to hostC and hostD by SSH. Now I can do it as follows: 1.connecting from hostA to hostB by RDP logon and there: 2.start putty client. I'd like to omit step 1 and connect from A to C and D directly On hostB I have admin acoount and configure port forwarding as follows: netsh interface portproxy add v4tov4 listenport=N1 connectaddress=hostC_IP connectport=N2 netsh interface portproxy add v4tov4 listenport=N3 connectaddress=hostD_IP connectport=N2 netsh interface portproxy show all: Listen on IPv4: Connect to IPv4: Address Port Address Port --------------- ---------- --------------- ---------- * N1 hostC_IP N2 * N3 hostD_IP N2 Now from hostB I can connect to either C and D: ssh localhost:N1 ssh localhost:N3 from hostA ssh hostB:N1 works too, but ssh hostB:N3 DON'T I guess the reason might be different subnets, still have no idea how to fix it. What should I do?

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  • Permissions Required for Sharepoint Backups

    - by Wyatt Barnett
    We are in the process of rolling out an extranet for some of our partners using WSS 3.0 as the platform. We already use it internally for a variety of things, and we are using the following powershell script to backup the server: param( $url="http://localhost", $backupFolder="c:\" ) [System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint") $site= new-Object Microsoft.SharePoint.SPSite($url) $names=$site.WebApplication.Sites.Names foreach ($name in $names) { $n2 = "" if ($name.Length -eq 0) { $n2="ROOT" } else { $n2 = $name } $tmp=$n2.Replace("/", "_") + ".sbk" $saveas = "" if ($backupFolder.Length -eq 0) { $saveas = $tmp } else { $saveas = join-path -path $backupFolder -childPath $tmp } $site.WebApplication.Sites.Backup($name, $saveas, "true") write-host "$n2 backed up to $saveas." } This script works perfectly on the current installation running as our domain backup user. On the new box, it fails when ran as the backup user--claiming "The web application located at http://extranet/" could not be found. That url does, in fact, work so I'm fairly certain it isn't anything that dumb and rather is some permissions issue. Especially because, when executed from my security context, the script works perfectly. I have tried making the backup user a farm owner, as well as added him to the various site collection admin groups on the extranet. The one major difference between the extranet and the intranet server is that the extranet has an alternative access mapping (for https://xnet.example.com) and also uses forms authentication for that mapping. Anyhow, what permissions (or other voodoo) do I need to setup to get this script to work properly?

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  • Port forwarding (portmap) works only locally

    - by Tag Wint
    There are four hosts hostA winXP hostB Win2003 hostC Linux RHEL hostD Linux RHEL hostA cannot connect to C and D directly, but B can hostA connects to hostB using VPN hostB and hostC belong to the same subnet1 hostD is in subnet2 From hostA I need to connect to hostC and hostD by SSH. Now I can do it as follows: 1.connecting from hostA to hostB by RDP logon and there: 2.start putty client. I'd like to omit step 1 and connect from A to C and D directly On hostB I have admin acoount and configure port forwarding as follows: netsh interface portproxy add v4tov4 listenport=N1 connectaddress=hostC_IP connectport=N2 netsh interface portproxy add v4tov4 listenport=N3 connectaddress=hostD_IP connectport=N2 netsh interface portproxy show all: Listen on IPv4: Connect to IPv4: Address Port Address Port --------------- ---------- --------------- ---------- * N1 hostC_IP N2 * N3 hostD_IP N2 Now from hostB I can connect to either C and D: ssh localhost:N1 ssh localhost:N3 from hostA ssh hostB:N1 works too, but ssh hostB:N3 DON'T I guess the reason might be different subnets, still have no idea how to fix it. What should I do?

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  • Fibonacci numbers in F#

    - by BobPalmer
    As you may have gathered from some of my previous posts, I've been spending some quality time at Project Euler.  Normally I do my solutions in C#, but since I have also started learning F#, it only made sense to switch over to F# to get my math coding fix. This week's post is just a small snippet - spefically, a simple function to return a fibonacci number given it's place in the sequence.  One popular example uses recursion: let rec fib n = if n < 2 then 1 else fib (n-2) + fib(n-1) While this is certainly elegant, the recursion is absolutely brutal on performance.  So I decided to spend a little time, and find an option that achieved the same functionality, but used a recursive function.  And since this is F#, I wanted to make sure I did it without the use of any mutable variables. Here's the solution I came up with: let rec fib n1 n2 c =    if c = 1 then        n2    else        fib n2 (n1+n2) (c-1);;let GetFib num =    (fib 1 1 num);;printfn "%A" (GetFib 1000);; Essentially, this function works through the sequence moving forward, passing the two most recent numbers and a counter to the recursive calls until it has achieved the desired number of iterations.  At that point, it returns the latest fibonacci number. Enjoy!

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  • Simplex Noise Help

    - by Alex Larsen
    Im Making A Minecraft Like Gae In XNA C# And I Need To Generate Land With Caves This Is The Code For Simplex I Have /// <summary> /// 1D simplex noise /// </summary> /// <param name="x"></param> /// <returns></returns> public static float Generate(float x) { int i0 = FastFloor(x); int i1 = i0 + 1; float x0 = x - i0; float x1 = x0 - 1.0f; float n0, n1; float t0 = 1.0f - x0 * x0; t0 *= t0; n0 = t0 * t0 * grad(perm[i0 & 0xff], x0); float t1 = 1.0f - x1 * x1; t1 *= t1; n1 = t1 * t1 * grad(perm[i1 & 0xff], x1); // The maximum value of this noise is 8*(3/4)^4 = 2.53125 // A factor of 0.395 scales to fit exactly within [-1,1] return 0.395f * (n0 + n1); } /// <summary> /// 2D simplex noise /// </summary> /// <param name="x"></param> /// <param name="y"></param> /// <returns></returns> public static float Generate(float x, float y) { const float F2 = 0.366025403f; // F2 = 0.5*(sqrt(3.0)-1.0) const float G2 = 0.211324865f; // G2 = (3.0-Math.sqrt(3.0))/6.0 float n0, n1, n2; // Noise contributions from the three corners // Skew the input space to determine which simplex cell we're in float s = (x + y) * F2; // Hairy factor for 2D float xs = x + s; float ys = y + s; int i = FastFloor(xs); int j = FastFloor(ys); float t = (float)(i + j) * G2; float X0 = i - t; // Unskew the cell origin back to (x,y) space float Y0 = j - t; float x0 = x - X0; // The x,y distances from the cell origin float y0 = y - Y0; // For the 2D case, the simplex shape is an equilateral triangle. // Determine which simplex we are in. int i1, j1; // Offsets for second (middle) corner of simplex in (i,j) coords if (x0 > y0) { i1 = 1; j1 = 0; } // lower triangle, XY order: (0,0)->(1,0)->(1,1) else { i1 = 0; j1 = 1; } // upper triangle, YX order: (0,0)->(0,1)->(1,1) // A step of (1,0) in (i,j) means a step of (1-c,-c) in (x,y), and // a step of (0,1) in (i,j) means a step of (-c,1-c) in (x,y), where // c = (3-sqrt(3))/6 float x1 = x0 - i1 + G2; // Offsets for middle corner in (x,y) unskewed coords float y1 = y0 - j1 + G2; float x2 = x0 - 1.0f + 2.0f * G2; // Offsets for last corner in (x,y) unskewed coords float y2 = y0 - 1.0f + 2.0f * G2; // Wrap the integer indices at 256, to avoid indexing perm[] out of bounds int ii = i % 256; int jj = j % 256; // Calculate the contribution from the three corners float t0 = 0.5f - x0 * x0 - y0 * y0; if (t0 < 0.0f) n0 = 0.0f; else { t0 *= t0; n0 = t0 * t0 * grad(perm[ii + perm[jj]], x0, y0); } float t1 = 0.5f - x1 * x1 - y1 * y1; if (t1 < 0.0f) n1 = 0.0f; else { t1 *= t1; n1 = t1 * t1 * grad(perm[ii + i1 + perm[jj + j1]], x1, y1); } float t2 = 0.5f - x2 * x2 - y2 * y2; if (t2 < 0.0f) n2 = 0.0f; else { t2 *= t2; n2 = t2 * t2 * grad(perm[ii + 1 + perm[jj + 1]], x2, y2); } // Add contributions from each corner to get the final noise value. // The result is scaled to return values in the interval [-1,1]. return 40.0f * (n0 + n1 + n2); // TODO: The scale factor is preliminary! } public static float Generate(float x, float y, float z) { // Simple skewing factors for the 3D case const float F3 = 0.333333333f; const float G3 = 0.166666667f; float n0, n1, n2, n3; // Noise contributions from the four corners // Skew the input space to determine which simplex cell we're in float s = (x + y + z) * F3; // Very nice and simple skew factor for 3D float xs = x + s; float ys = y + s; float zs = z + s; int i = FastFloor(xs); int j = FastFloor(ys); int k = FastFloor(zs); float t = (float)(i + j + k) * G3; float X0 = i - t; // Unskew the cell origin back to (x,y,z) space float Y0 = j - t; float Z0 = k - t; float x0 = x - X0; // The x,y,z distances from the cell origin float y0 = y - Y0; float z0 = z - Z0; // For the 3D case, the simplex shape is a slightly irregular tetrahedron. // Determine which simplex we are in. int i1, j1, k1; // Offsets for second corner of simplex in (i,j,k) coords int i2, j2, k2; // Offsets for third corner of simplex in (i,j,k) coords /* This code would benefit from a backport from the GLSL version! */ if (x0 >= y0) { if (y0 >= z0) { i1 = 1; j1 = 0; k1 = 0; i2 = 1; j2 = 1; k2 = 0; } // X Y Z order else if (x0 >= z0) { i1 = 1; j1 = 0; k1 = 0; i2 = 1; j2 = 0; k2 = 1; } // X Z Y order else { i1 = 0; j1 = 0; k1 = 1; i2 = 1; j2 = 0; k2 = 1; } // Z X Y order } else { // x0<y0 if (y0 < z0) { i1 = 0; j1 = 0; k1 = 1; i2 = 0; j2 = 1; k2 = 1; } // Z Y X order else if (x0 < z0) { i1 = 0; j1 = 1; k1 = 0; i2 = 0; j2 = 1; k2 = 1; } // Y Z X order else { i1 = 0; j1 = 1; k1 = 0; i2 = 1; j2 = 1; k2 = 0; } // Y X Z order } // A step of (1,0,0) in (i,j,k) means a step of (1-c,-c,-c) in (x,y,z), // a step of (0,1,0) in (i,j,k) means a step of (-c,1-c,-c) in (x,y,z), and // a step of (0,0,1) in (i,j,k) means a step of (-c,-c,1-c) in (x,y,z), where // c = 1/6. float x1 = x0 - i1 + G3; // Offsets for second corner in (x,y,z) coords float y1 = y0 - j1 + G3; float z1 = z0 - k1 + G3; float x2 = x0 - i2 + 2.0f * G3; // Offsets for third corner in (x,y,z) coords float y2 = y0 - j2 + 2.0f * G3; float z2 = z0 - k2 + 2.0f * G3; float x3 = x0 - 1.0f + 3.0f * G3; // Offsets for last corner in (x,y,z) coords float y3 = y0 - 1.0f + 3.0f * G3; float z3 = z0 - 1.0f + 3.0f * G3; // Wrap the integer indices at 256, to avoid indexing perm[] out of bounds int ii = i % 256; int jj = j % 256; int kk = k % 256; // Calculate the contribution from the four corners float t0 = 0.6f - x0 * x0 - y0 * y0 - z0 * z0; if (t0 < 0.0f) n0 = 0.0f; else { t0 *= t0; n0 = t0 * t0 * grad(perm[ii + perm[jj + perm[kk]]], x0, y0, z0); } float t1 = 0.6f - x1 * x1 - y1 * y1 - z1 * z1; if (t1 < 0.0f) n1 = 0.0f; else { t1 *= t1; n1 = t1 * t1 * grad(perm[ii + i1 + perm[jj + j1 + perm[kk + k1]]], x1, y1, z1); } float t2 = 0.6f - x2 * x2 - y2 * y2 - z2 * z2; if (t2 < 0.0f) n2 = 0.0f; else { t2 *= t2; n2 = t2 * t2 * grad(perm[ii + i2 + perm[jj + j2 + perm[kk + k2]]], x2, y2, z2); } float t3 = 0.6f - x3 * x3 - y3 * y3 - z3 * z3; if (t3 < 0.0f) n3 = 0.0f; else { t3 *= t3; n3 = t3 * t3 * grad(perm[ii + 1 + perm[jj + 1 + perm[kk + 1]]], x3, y3, z3); } // Add contributions from each corner to get the final noise value. // The result is scaled to stay just inside [-1,1] return 32.0f * (n0 + n1 + n2 + n3); // TODO: The scale factor is preliminary! } private static byte[] perm = new byte[512] { 151,160,137,91,90,15, 131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23, 190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33, 88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166, 77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244, 102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196, 135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123, 5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42, 223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9, 129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228, 251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107, 49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254, 138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180, 151,160,137,91,90,15, 131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23, 190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33, 88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166, 77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244, 102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196, 135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123, 5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42, 223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9, 129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228, 251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107, 49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254, 138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180 }; private static int FastFloor(float x) { return (x > 0) ? ((int)x) : (((int)x) - 1); } private static float grad(int hash, float x) { int h = hash & 15; float grad = 1.0f + (h & 7); // Gradient value 1.0, 2.0, ..., 8.0 if ((h & 8) != 0) grad = -grad; // Set a random sign for the gradient return (grad * x); // Multiply the gradient with the distance } private static float grad(int hash, float x, float y) { int h = hash & 7; // Convert low 3 bits of hash code float u = h < 4 ? x : y; // into 8 simple gradient directions, float v = h < 4 ? y : x; // and compute the dot product with (x,y). return ((h & 1) != 0 ? -u : u) + ((h & 2) != 0 ? -2.0f * v : 2.0f * v); } private static float grad(int hash, float x, float y, float z) { int h = hash & 15; // Convert low 4 bits of hash code into 12 simple float u = h < 8 ? x : y; // gradient directions, and compute dot product. float v = h < 4 ? y : h == 12 || h == 14 ? x : z; // Fix repeats at h = 12 to 15 return ((h & 1) != 0 ? -u : u) + ((h & 2) != 0 ? -v : v); } private static float grad(int hash, float x, float y, float z, float t) { int h = hash & 31; // Convert low 5 bits of hash code into 32 simple float u = h < 24 ? x : y; // gradient directions, and compute dot product. float v = h < 16 ? y : z; float w = h < 8 ? z : t; return ((h & 1) != 0 ? -u : u) + ((h & 2) != 0 ? -v : v) + ((h & 4) != 0 ? -w : w); } This Is My World Generation Code Block[,] BlocksInMap = new Block[1024, 256]; public bool IsWorldGenerated = false; Random r = new Random(); private void RunThread() { for (int BH = 0; BH <= 256; BH++) { for (int BW = 0; BW <= 1024; BW++) { Block b = new Block(); if (BH >= 192) { } BlocksInMap[BW, BH] = b; } } IsWorldGenerated = true; } public void GenWorld() { new Thread(new ThreadStart(RunThread)).Start(); } And This Is A Example Of How I Set Blocks Block b = new Block(); b.BlockType = = Block.BlockTypes.Air; This Is A Example Of How I Set Models foreach (Block b in MyWorld) { switch(b.BlockType) { case Block.BlockTypes.Dirt: b.Model = DirtModel; break; ect. } } How Would I Use These To Generate To World (The Block Array) And If Possible Thread It More? btw It's 1024 Wide And 256 Tall

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  • assigning in system of differential equations

    - by Alireza
    hi every one! when i solve numerically a system of two differential equations: s1:=diff(nDi, t)=...; s2:=diff(nT, t)=...; ics:={...}; #initial condition. sys := {s1, s2, ics}: sol:=dsolve(sys,numeric); with respect to "t",then the solution (for example)for "t=4" is of the form, sol(4): [t=4, n1(t)=const1, n2(t)=const2]. now, how is possible to use values of n1(t) and n2(t) for all "t"'s in another equation, namely "p", which involved n1(t) or n2(t)(like: {p=a+n1(t)*n2(t)+f(t)},where "a" and "f(t)" are defined), and to plot "p" for an interval of "t"?

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  • NSNumberFormatter weirdness with NSNumberFormatterPercentStyle

    - by rein
    Hi, I need to parse some text in a UITextField and turn it into a percentage. Ideally, I'd like the user to either type something like 12 or 12% into the text field and have that be parsed into a number as a percentage. Here's what's weird. The number formatter seems to not like 12 and seems to divide 12% by 10000 instead of 100: NSNumberFormatter *formatter = [[[NSNumberFormatter alloc] init] autorelease]; [formatter setNumberStyle:NSNumberFormatterPercentStyle]; NSNumber *n1 = [formatter numberFromString:@"12"]; NSNumber *n2 = [formatter numberFromString:@"12%"]; NSLog(@"n1 = %@", n1); // n1 = (null) NSLog(@"n2 = %@", n2); // n2 = 0.0012 How do I get the formatter to return 0.12 as expected? EDIT: it seems to only happen if the formatter fails first. If the formatter does not fail it returns 0.12 as expected. Strange.

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  • Django url tag multiple parameters

    - by Overdose
    I have two similar codes. The first one works as expected. urlpatterns = patterns('', (r'^(?P<n1>\d)/test/', test), (r'', test2), {% url testapp.views.test n1=5 %} But adding the second parameter makes the result return empty string. urlpatterns = patterns('', (r'^(?P<n1>\d)/test(?P<n2>\d)/', test), (r'', test2),) {% url testapp.views.test n1=5, n2=2 %} Views signature: def test(request, n1, n2=1):

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  • How do you calculate div and mod of floating point numbers?

    - by boost
    In Perl, the % operator seems to assume integers. For instance: sub foo { my $n1 = shift; my $n2 = shift; print "perl's mod=" . $n1 % $n2, "\n"; my $res = $n1 / $n2; my $t = int($res); print "my div=$t", "\n"; $res = $res - $t; $res = $res * $n2; print "my mod=" . $res . "\n\n"; } foo( 3044.952963, 7.1 ); foo( 3044.952963, -7.1 ); foo( -3044.952963, 7.1 ); foo( -3044.952963, -7.1 ); gives perl's mod=6 my div=428 my mod=6.15296300000033 perl's mod=-1 my div=-428 my mod=6.15296300000033 perl's mod=1 my div=-428 my mod=-6.15296300000033 perl's mod=-6 my div=428 my mod=-6.15296300000033 Now as you can see, I've come up with a "solution" already for calculating div and mod. However, what I don't understand is what effect the sign of each argument should have on the result. Wouldn't the div always be positive, being the number of times n2 fits into n1? How's the arithmetic supposed to work in this situation?

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  • How to get balanced diagrams from graphviz?

    - by user360872
    Is there a setting in graphviz to generate balanced diagrams like this: When diagram is more complex like below - it isn't balanced like that above (4 is below **). Code to generate second diagram: graph { n1 [label="+"]; n1 -- n2; n2 [label="/"]; n2 -- n3; n3 [label="*"]; n3 -- n4; n4 [label="1"]; n3 -- n5; n5 [label="2"]; n2 -- n6; n6 [label="3"]; n1 -- n7; n7 [label="**"]; n7 -- n8; n8 [label="4"]; n7 -- n9; n9 [label="5"]; }

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  • Pivot Table grand total across columns

    - by Jon
    I'm using Excel 2010 and Power Pivot. I'm trying to calculate confidence and velocity for a development team. I'm extracting some information from our time and defect system each day and building a data set. What I need to do with Excel is do the calculations. So each day I add to my data set 1 row per task in the current project, estimate for that task and the time spent on that task. What I want to calculate is the estimate/actual for each task but also for each person. The trouble is that each day the actual is cumulative so I need to pick out the maximum value for each task. The estimate should remain unchanged. I can make this work at the task level with a calculated measure (=MAX(worked)/MAX(estimate)) but I don't know how to total this up for a person. I need the sum of the max worked for each task. So a dataset might look like: Name Task Estimate Worked N1 T1 3 1 N2 T2 3 1 N3 T3 4 1 N1 T1 3 2 N2 T4 5 1 N3 T3 4 2 N1 T5 1 2 N2 T6 2 3 N3 T7 3 2 What I want to see is for task T1 2 days were worked against an estimate of 3 days - so 2/3. For person N1 I want to see that they worked a total of 4 days against an estimate of 4 days so 4/4. For person N2 they worked 5 days for an estimate of 10 days. Any ideas on how I can achieve this?

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  • How John Got 15x Improvement Without Really Trying

    - by rchrd
    The following article was published on a Sun Microsystems website a number of years ago by John Feo. It is still useful and worth preserving. So I'm republishing it here.  How I Got 15x Improvement Without Really Trying John Feo, Sun Microsystems Taking ten "personal" program codes used in scientific and engineering research, the author was able to get from 2 to 15 times performance improvement easily by applying some simple general optimization techniques. Introduction Scientific research based on computer simulation depends on the simulation for advancement. The research can advance only as fast as the computational codes can execute. The codes' efficiency determines both the rate and quality of results. In the same amount of time, a faster program can generate more results and can carry out a more detailed simulation of physical phenomena than a slower program. Highly optimized programs help science advance quickly and insure that monies supporting scientific research are used as effectively as possible. Scientific computer codes divide into three broad categories: ISV, community, and personal. ISV codes are large, mature production codes developed and sold commercially. The codes improve slowly over time both in methods and capabilities, and they are well tuned for most vendor platforms. Since the codes are mature and complex, there are few opportunities to improve their performance solely through code optimization. Improvements of 10% to 15% are typical. Examples of ISV codes are DYNA3D, Gaussian, and Nastran. Community codes are non-commercial production codes used by a particular research field. Generally, they are developed and distributed by a single academic or research institution with assistance from the community. Most users just run the codes, but some develop new methods and extensions that feed back into the general release. The codes are available on most vendor platforms. Since these codes are younger than ISV codes, there are more opportunities to optimize the source code. Improvements of 50% are not unusual. Examples of community codes are AMBER, CHARM, BLAST, and FASTA. Personal codes are those written by single users or small research groups for their own use. These codes are not distributed, but may be passed from professor-to-student or student-to-student over several years. They form the primordial ocean of applications from which community and ISV codes emerge. Government research grants pay for the development of most personal codes. This paper reports on the nature and performance of this class of codes. Over the last year, I have looked at over two dozen personal codes from more than a dozen research institutions. The codes cover a variety of scientific fields, including astronomy, atmospheric sciences, bioinformatics, biology, chemistry, geology, and physics. The sources range from a few hundred lines to more than ten thousand lines, and are written in Fortran, Fortran 90, C, and C++. For the most part, the codes are modular, documented, and written in a clear, straightforward manner. They do not use complex language features, advanced data structures, programming tricks, or libraries. I had little trouble understanding what the codes did or how data structures were used. Most came with a makefile. Surprisingly, only one of the applications is parallel. All developers have access to parallel machines, so availability is not an issue. Several tried to parallelize their applications, but stopped after encountering difficulties. Lack of education and a perception that parallelism is difficult prevented most from trying. I parallelized several of the codes using OpenMP, and did not judge any of the codes as difficult to parallelize. Even more surprising than the lack of parallelism is the inefficiency of the codes. I was able to get large improvements in performance in a matter of a few days applying simple optimization techniques. Table 1 lists ten representative codes [names and affiliation are omitted to preserve anonymity]. Improvements on one processor range from 2x to 15.5x with a simple average of 4.75x. I did not use sophisticated performance tools or drill deep into the program's execution character as one would do when tuning ISV or community codes. Using only a profiler and source line timers, I identified inefficient sections of code and improved their performance by inspection. The changes were at a high level. I am sure there is another factor of 2 or 3 in each code, and more if the codes are parallelized. The study’s results show that personal scientific codes are running many times slower than they should and that the problem is pervasive. Computational scientists are not sloppy programmers; however, few are trained in the art of computer programming or code optimization. I found that most have a working knowledge of some programming language and standard software engineering practices; but they do not know, or think about, how to make their programs run faster. They simply do not know the standard techniques used to make codes run faster. In fact, they do not even perceive that such techniques exist. The case studies described in this paper show that applying simple, well known techniques can significantly increase the performance of personal codes. It is important that the scientific community and the Government agencies that support scientific research find ways to better educate academic scientific programmers. The inefficiency of their codes is so bad that it is retarding both the quality and progress of scientific research. # cacheperformance redundantoperations loopstructures performanceimprovement 1 x x 15.5 2 x 2.8 3 x x 2.5 4 x 2.1 5 x x 2.0 6 x 5.0 7 x 5.8 8 x 6.3 9 2.2 10 x x 3.3 Table 1 — Area of improvement and performance gains of 10 codes The remainder of the paper is organized as follows: sections 2, 3, and 4 discuss the three most common sources of inefficiencies in the codes studied. These are cache performance, redundant operations, and loop structures. Each section includes several examples. The last section summaries the work and suggests a possible solution to the issues raised. Optimizing cache performance Commodity microprocessor systems use caches to increase memory bandwidth and reduce memory latencies. Typical latencies from processor to L1, L2, local, and remote memory are 3, 10, 50, and 200 cycles, respectively. Moreover, bandwidth falls off dramatically as memory distances increase. Programs that do not use cache effectively run many times slower than programs that do. When optimizing for cache, the biggest performance gains are achieved by accessing data in cache order and reusing data to amortize the overhead of cache misses. Secondary considerations are prefetching, associativity, and replacement; however, the understanding and analysis required to optimize for the latter are probably beyond the capabilities of the non-expert. Much can be gained simply by accessing data in the correct order and maximizing data reuse. 6 out of the 10 codes studied here benefited from such high level optimizations. Array Accesses The most important cache optimization is the most basic: accessing Fortran array elements in column order and C array elements in row order. Four of the ten codes—1, 2, 4, and 10—got it wrong. Compilers will restructure nested loops to optimize cache performance, but may not do so if the loop structure is too complex, or the loop body includes conditionals, complex addressing, or function calls. In code 1, the compiler failed to invert a key loop because of complex addressing do I = 0, 1010, delta_x IM = I - delta_x IP = I + delta_x do J = 5, 995, delta_x JM = J - delta_x JP = J + delta_x T1 = CA1(IP, J) + CA1(I, JP) T2 = CA1(IM, J) + CA1(I, JM) S1 = T1 + T2 - 4 * CA1(I, J) CA(I, J) = CA1(I, J) + D * S1 end do end do In code 2, the culprit is conditionals do I = 1, N do J = 1, N If (IFLAG(I,J) .EQ. 0) then T1 = Value(I, J-1) T2 = Value(I-1, J) T3 = Value(I, J) T4 = Value(I+1, J) T5 = Value(I, J+1) Value(I,J) = 0.25 * (T1 + T2 + T5 + T4) Delta = ABS(T3 - Value(I,J)) If (Delta .GT. MaxDelta) MaxDelta = Delta endif enddo enddo I fixed both programs by inverting the loops by hand. Code 10 has three-dimensional arrays and triply nested loops. The structure of the most computationally intensive loops is too complex to invert automatically or by hand. The only practical solution is to transpose the arrays so that the dimension accessed by the innermost loop is in cache order. The arrays can be transposed at construction or prior to entering a computationally intensive section of code. The former requires all array references to be modified, while the latter is cost effective only if the cost of the transpose is amortized over many accesses. I used the second approach to optimize code 10. Code 5 has four-dimensional arrays and loops are nested four deep. For all of the reasons cited above the compiler is not able to restructure three key loops. Assume C arrays and let the four dimensions of the arrays be i, j, k, and l. In the original code, the index structure of the three loops is L1: for i L2: for i L3: for i for l for l for j for k for j for k for j for k for l So only L3 accesses array elements in cache order. L1 is a very complex loop—much too complex to invert. I brought the loop into cache alignment by transposing the second and fourth dimensions of the arrays. Since the code uses a macro to compute all array indexes, I effected the transpose at construction and changed the macro appropriately. The dimensions of the new arrays are now: i, l, k, and j. L3 is a simple loop and easily inverted. L2 has a loop-carried scalar dependence in k. By promoting the scalar name that carries the dependence to an array, I was able to invert the third and fourth subloops aligning the loop with cache. Code 5 is by far the most difficult of the four codes to optimize for array accesses; but the knowledge required to fix the problems is no more than that required for the other codes. I would judge this code at the limits of, but not beyond, the capabilities of appropriately trained computational scientists. Array Strides When a cache miss occurs, a line (64 bytes) rather than just one word is loaded into the cache. If data is accessed stride 1, than the cost of the miss is amortized over 8 words. Any stride other than one reduces the cost savings. Two of the ten codes studied suffered from non-unit strides. The codes represent two important classes of "strided" codes. Code 1 employs a multi-grid algorithm to reduce time to convergence. The grids are every tenth, fifth, second, and unit element. Since time to convergence is inversely proportional to the distance between elements, coarse grids converge quickly providing good starting values for finer grids. The better starting values further reduce the time to convergence. The downside is that grids of every nth element, n > 1, introduce non-unit strides into the computation. In the original code, much of the savings of the multi-grid algorithm were lost due to this problem. I eliminated the problem by compressing (copying) coarse grids into continuous memory, and rewriting the computation as a function of the compressed grid. On convergence, I copied the final values of the compressed grid back to the original grid. The savings gained from unit stride access of the compressed grid more than paid for the cost of copying. Using compressed grids, the loop from code 1 included in the previous section becomes do j = 1, GZ do i = 1, GZ T1 = CA(i+0, j-1) + CA(i-1, j+0) T4 = CA1(i+1, j+0) + CA1(i+0, j+1) S1 = T1 + T4 - 4 * CA1(i+0, j+0) CA(i+0, j+0) = CA1(i+0, j+0) + DD * S1 enddo enddo where CA and CA1 are compressed arrays of size GZ. Code 7 traverses a list of objects selecting objects for later processing. The labels of the selected objects are stored in an array. The selection step has unit stride, but the processing steps have irregular stride. A fix is to save the parameters of the selected objects in temporary arrays as they are selected, and pass the temporary arrays to the processing functions. The fix is practical if the same parameters are used in selection as in processing, or if processing comprises a series of distinct steps which use overlapping subsets of the parameters. Both conditions are true for code 7, so I achieved significant improvement by copying parameters to temporary arrays during selection. Data reuse In the previous sections, we optimized for spatial locality. It is also important to optimize for temporal locality. Once read, a datum should be used as much as possible before it is forced from cache. Loop fusion and loop unrolling are two techniques that increase temporal locality. Unfortunately, both techniques increase register pressure—as loop bodies become larger, the number of registers required to hold temporary values grows. Once register spilling occurs, any gains evaporate quickly. For multiprocessors with small register sets or small caches, the sweet spot can be very small. In the ten codes presented here, I found no opportunities for loop fusion and only two opportunities for loop unrolling (codes 1 and 3). In code 1, unrolling the outer and inner loop one iteration increases the number of result values computed by the loop body from 1 to 4, do J = 1, GZ-2, 2 do I = 1, GZ-2, 2 T1 = CA1(i+0, j-1) + CA1(i-1, j+0) T2 = CA1(i+1, j-1) + CA1(i+0, j+0) T3 = CA1(i+0, j+0) + CA1(i-1, j+1) T4 = CA1(i+1, j+0) + CA1(i+0, j+1) T5 = CA1(i+2, j+0) + CA1(i+1, j+1) T6 = CA1(i+1, j+1) + CA1(i+0, j+2) T7 = CA1(i+2, j+1) + CA1(i+1, j+2) S1 = T1 + T4 - 4 * CA1(i+0, j+0) S2 = T2 + T5 - 4 * CA1(i+1, j+0) S3 = T3 + T6 - 4 * CA1(i+0, j+1) S4 = T4 + T7 - 4 * CA1(i+1, j+1) CA(i+0, j+0) = CA1(i+0, j+0) + DD * S1 CA(i+1, j+0) = CA1(i+1, j+0) + DD * S2 CA(i+0, j+1) = CA1(i+0, j+1) + DD * S3 CA(i+1, j+1) = CA1(i+1, j+1) + DD * S4 enddo enddo The loop body executes 12 reads, whereas as the rolled loop shown in the previous section executes 20 reads to compute the same four values. In code 3, two loops are unrolled 8 times and one loop is unrolled 4 times. Here is the before for (k = 0; k < NK[u]; k++) { sum = 0.0; for (y = 0; y < NY; y++) { sum += W[y][u][k] * delta[y]; } backprop[i++]=sum; } and after code for (k = 0; k < KK - 8; k+=8) { sum0 = 0.0; sum1 = 0.0; sum2 = 0.0; sum3 = 0.0; sum4 = 0.0; sum5 = 0.0; sum6 = 0.0; sum7 = 0.0; for (y = 0; y < NY; y++) { sum0 += W[y][0][k+0] * delta[y]; sum1 += W[y][0][k+1] * delta[y]; sum2 += W[y][0][k+2] * delta[y]; sum3 += W[y][0][k+3] * delta[y]; sum4 += W[y][0][k+4] * delta[y]; sum5 += W[y][0][k+5] * delta[y]; sum6 += W[y][0][k+6] * delta[y]; sum7 += W[y][0][k+7] * delta[y]; } backprop[k+0] = sum0; backprop[k+1] = sum1; backprop[k+2] = sum2; backprop[k+3] = sum3; backprop[k+4] = sum4; backprop[k+5] = sum5; backprop[k+6] = sum6; backprop[k+7] = sum7; } for one of the loops unrolled 8 times. Optimizing for temporal locality is the most difficult optimization considered in this paper. The concepts are not difficult, but the sweet spot is small. Identifying where the program can benefit from loop unrolling or loop fusion is not trivial. Moreover, it takes some effort to get it right. Still, educating scientific programmers about temporal locality and teaching them how to optimize for it will pay dividends. Reducing instruction count Execution time is a function of instruction count. Reduce the count and you usually reduce the time. The best solution is to use a more efficient algorithm; that is, an algorithm whose order of complexity is smaller, that converges quicker, or is more accurate. Optimizing source code without changing the algorithm yields smaller, but still significant, gains. This paper considers only the latter because the intent is to study how much better codes can run if written by programmers schooled in basic code optimization techniques. The ten codes studied benefited from three types of "instruction reducing" optimizations. The two most prevalent were hoisting invariant memory and data operations out of inner loops. The third was eliminating unnecessary data copying. The nature of these inefficiencies is language dependent. Memory operations The semantics of C make it difficult for the compiler to determine all the invariant memory operations in a loop. The problem is particularly acute for loops in functions since the compiler may not know the values of the function's parameters at every call site when compiling the function. Most compilers support pragmas to help resolve ambiguities; however, these pragmas are not comprehensive and there is no standard syntax. To guarantee that invariant memory operations are not executed repetitively, the user has little choice but to hoist the operations by hand. The problem is not as severe in Fortran programs because in the absence of equivalence statements, it is a violation of the language's semantics for two names to share memory. Codes 3 and 5 are C programs. In both cases, the compiler did not hoist all invariant memory operations from inner loops. Consider the following loop from code 3 for (y = 0; y < NY; y++) { i = 0; for (u = 0; u < NU; u++) { for (k = 0; k < NK[u]; k++) { dW[y][u][k] += delta[y] * I1[i++]; } } } Since dW[y][u] can point to the same memory space as delta for one or more values of y and u, assignment to dW[y][u][k] may change the value of delta[y]. In reality, dW and delta do not overlap in memory, so I rewrote the loop as for (y = 0; y < NY; y++) { i = 0; Dy = delta[y]; for (u = 0; u < NU; u++) { for (k = 0; k < NK[u]; k++) { dW[y][u][k] += Dy * I1[i++]; } } } Failure to hoist invariant memory operations may be due to complex address calculations. If the compiler can not determine that the address calculation is invariant, then it can hoist neither the calculation nor the associated memory operations. As noted above, code 5 uses a macro to address four-dimensional arrays #define MAT4D(a,q,i,j,k) (double *)((a)->data + (q)*(a)->strides[0] + (i)*(a)->strides[3] + (j)*(a)->strides[2] + (k)*(a)->strides[1]) The macro is too complex for the compiler to understand and so, it does not identify any subexpressions as loop invariant. The simplest way to eliminate the address calculation from the innermost loop (over i) is to define a0 = MAT4D(a,q,0,j,k) before the loop and then replace all instances of *MAT4D(a,q,i,j,k) in the loop with a0[i] A similar problem appears in code 6, a Fortran program. The key loop in this program is do n1 = 1, nh nx1 = (n1 - 1) / nz + 1 nz1 = n1 - nz * (nx1 - 1) do n2 = 1, nh nx2 = (n2 - 1) / nz + 1 nz2 = n2 - nz * (nx2 - 1) ndx = nx2 - nx1 ndy = nz2 - nz1 gxx = grn(1,ndx,ndy) gyy = grn(2,ndx,ndy) gxy = grn(3,ndx,ndy) balance(n1,1) = balance(n1,1) + (force(n2,1) * gxx + force(n2,2) * gxy) * h1 balance(n1,2) = balance(n1,2) + (force(n2,1) * gxy + force(n2,2) * gyy)*h1 end do end do The programmer has written this loop well—there are no loop invariant operations with respect to n1 and n2. However, the loop resides within an iterative loop over time and the index calculations are independent with respect to time. Trading space for time, I precomputed the index values prior to the entering the time loop and stored the values in two arrays. I then replaced the index calculations with reads of the arrays. Data operations Ways to reduce data operations can appear in many forms. Implementing a more efficient algorithm produces the biggest gains. The closest I came to an algorithm change was in code 4. This code computes the inner product of K-vectors A(i) and B(j), 0 = i < N, 0 = j < M, for most values of i and j. Since the program computes most of the NM possible inner products, it is more efficient to compute all the inner products in one triply-nested loop rather than one at a time when needed. The savings accrue from reading A(i) once for all B(j) vectors and from loop unrolling. for (i = 0; i < N; i+=8) { for (j = 0; j < M; j++) { sum0 = 0.0; sum1 = 0.0; sum2 = 0.0; sum3 = 0.0; sum4 = 0.0; sum5 = 0.0; sum6 = 0.0; sum7 = 0.0; for (k = 0; k < K; k++) { sum0 += A[i+0][k] * B[j][k]; sum1 += A[i+1][k] * B[j][k]; sum2 += A[i+2][k] * B[j][k]; sum3 += A[i+3][k] * B[j][k]; sum4 += A[i+4][k] * B[j][k]; sum5 += A[i+5][k] * B[j][k]; sum6 += A[i+6][k] * B[j][k]; sum7 += A[i+7][k] * B[j][k]; } C[i+0][j] = sum0; C[i+1][j] = sum1; C[i+2][j] = sum2; C[i+3][j] = sum3; C[i+4][j] = sum4; C[i+5][j] = sum5; C[i+6][j] = sum6; C[i+7][j] = sum7; }} This change requires knowledge of a typical run; i.e., that most inner products are computed. The reasons for the change, however, derive from basic optimization concepts. It is the type of change easily made at development time by a knowledgeable programmer. In code 5, we have the data version of the index optimization in code 6. Here a very expensive computation is a function of the loop indices and so cannot be hoisted out of the loop; however, the computation is invariant with respect to an outer iterative loop over time. We can compute its value for each iteration of the computation loop prior to entering the time loop and save the values in an array. The increase in memory required to store the values is small in comparison to the large savings in time. The main loop in Code 8 is doubly nested. The inner loop includes a series of guarded computations; some are a function of the inner loop index but not the outer loop index while others are a function of the outer loop index but not the inner loop index for (j = 0; j < N; j++) { for (i = 0; i < M; i++) { r = i * hrmax; R = A[j]; temp = (PRM[3] == 0.0) ? 1.0 : pow(r, PRM[3]); high = temp * kcoeff * B[j] * PRM[2] * PRM[4]; low = high * PRM[6] * PRM[6] / (1.0 + pow(PRM[4] * PRM[6], 2.0)); kap = (R > PRM[6]) ? high * R * R / (1.0 + pow(PRM[4]*r, 2.0) : low * pow(R/PRM[6], PRM[5]); < rest of loop omitted > }} Note that the value of temp is invariant to j. Thus, we can hoist the computation for temp out of the loop and save its values in an array. for (i = 0; i < M; i++) { r = i * hrmax; TEMP[i] = pow(r, PRM[3]); } [N.B. – the case for PRM[3] = 0 is omitted and will be reintroduced later.] We now hoist out of the inner loop the computations invariant to i. Since the conditional guarding the value of kap is invariant to i, it behooves us to hoist the computation out of the inner loop, thereby executing the guard once rather than M times. The final version of the code is for (j = 0; j < N; j++) { R = rig[j] / 1000.; tmp1 = kcoeff * par[2] * beta[j] * par[4]; tmp2 = 1.0 + (par[4] * par[4] * par[6] * par[6]); tmp3 = 1.0 + (par[4] * par[4] * R * R); tmp4 = par[6] * par[6] / tmp2; tmp5 = R * R / tmp3; tmp6 = pow(R / par[6], par[5]); if ((par[3] == 0.0) && (R > par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * tmp5; } else if ((par[3] == 0.0) && (R <= par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * tmp4 * tmp6; } else if ((par[3] != 0.0) && (R > par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * TEMP[i] * tmp5; } else if ((par[3] != 0.0) && (R <= par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * TEMP[i] * tmp4 * tmp6; } for (i = 0; i < M; i++) { kap = KAP[i]; r = i * hrmax; < rest of loop omitted > } } Maybe not the prettiest piece of code, but certainly much more efficient than the original loop, Copy operations Several programs unnecessarily copy data from one data structure to another. This problem occurs in both Fortran and C programs, although it manifests itself differently in the two languages. Code 1 declares two arrays—one for old values and one for new values. At the end of each iteration, the array of new values is copied to the array of old values to reset the data structures for the next iteration. This problem occurs in Fortran programs not included in this study and in both Fortran 77 and Fortran 90 code. Introducing pointers to the arrays and swapping pointer values is an obvious way to eliminate the copying; but pointers is not a feature that many Fortran programmers know well or are comfortable using. An easy solution not involving pointers is to extend the dimension of the value array by 1 and use the last dimension to differentiate between arrays at different times. For example, if the data space is N x N, declare the array (N, N, 2). Then store the problem’s initial values in (_, _, 2) and define the scalar names new = 2 and old = 1. At the start of each iteration, swap old and new to reset the arrays. The old–new copy problem did not appear in any C program. In programs that had new and old values, the code swapped pointers to reset data structures. Where unnecessary coping did occur is in structure assignment and parameter passing. Structures in C are handled much like scalars. Assignment causes the data space of the right-hand name to be copied to the data space of the left-hand name. Similarly, when a structure is passed to a function, the data space of the actual parameter is copied to the data space of the formal parameter. If the structure is large and the assignment or function call is in an inner loop, then copying costs can grow quite large. While none of the ten programs considered here manifested this problem, it did occur in programs not included in the study. A simple fix is always to refer to structures via pointers. Optimizing loop structures Since scientific programs spend almost all their time in loops, efficient loops are the key to good performance. Conditionals, function calls, little instruction level parallelism, and large numbers of temporary values make it difficult for the compiler to generate tightly packed, highly efficient code. Conditionals and function calls introduce jumps that disrupt code flow. Users should eliminate or isolate conditionls to their own loops as much as possible. Often logical expressions can be substituted for if-then-else statements. For example, code 2 includes the following snippet MaxDelta = 0.0 do J = 1, N do I = 1, M < code omitted > Delta = abs(OldValue ? NewValue) if (Delta > MaxDelta) MaxDelta = Delta enddo enddo if (MaxDelta .gt. 0.001) goto 200 Since the only use of MaxDelta is to control the jump to 200 and all that matters is whether or not it is greater than 0.001, I made MaxDelta a boolean and rewrote the snippet as MaxDelta = .false. do J = 1, N do I = 1, M < code omitted > Delta = abs(OldValue ? NewValue) MaxDelta = MaxDelta .or. (Delta .gt. 0.001) enddo enddo if (MaxDelta) goto 200 thereby, eliminating the conditional expression from the inner loop. A microprocessor can execute many instructions per instruction cycle. Typically, it can execute one or more memory, floating point, integer, and jump operations. To be executed simultaneously, the operations must be independent. Thick loops tend to have more instruction level parallelism than thin loops. Moreover, they reduce memory traffice by maximizing data reuse. Loop unrolling and loop fusion are two techniques to increase the size of loop bodies. Several of the codes studied benefitted from loop unrolling, but none benefitted from loop fusion. This observation is not too surpising since it is the general tendency of programmers to write thick loops. As loops become thicker, the number of temporary values grows, increasing register pressure. If registers spill, then memory traffic increases and code flow is disrupted. A thick loop with many temporary values may execute slower than an equivalent series of thin loops. The biggest gain will be achieved if the thick loop can be split into a series of independent loops eliminating the need to write and read temporary arrays. I found such an occasion in code 10 where I split the loop do i = 1, n do j = 1, m A24(j,i)= S24(j,i) * T24(j,i) + S25(j,i) * U25(j,i) B24(j,i)= S24(j,i) * T25(j,i) + S25(j,i) * U24(j,i) A25(j,i)= S24(j,i) * C24(j,i) + S25(j,i) * V24(j,i) B25(j,i)= S24(j,i) * U25(j,i) + S25(j,i) * V25(j,i) C24(j,i)= S26(j,i) * T26(j,i) + S27(j,i) * U26(j,i) D24(j,i)= S26(j,i) * T27(j,i) + S27(j,i) * V26(j,i) C25(j,i)= S27(j,i) * S28(j,i) + S26(j,i) * U28(j,i) D25(j,i)= S27(j,i) * T28(j,i) + S26(j,i) * V28(j,i) end do end do into two disjoint loops do i = 1, n do j = 1, m A24(j,i)= S24(j,i) * T24(j,i) + S25(j,i) * U25(j,i) B24(j,i)= S24(j,i) * T25(j,i) + S25(j,i) * U24(j,i) A25(j,i)= S24(j,i) * C24(j,i) + S25(j,i) * V24(j,i) B25(j,i)= S24(j,i) * U25(j,i) + S25(j,i) * V25(j,i) end do end do do i = 1, n do j = 1, m C24(j,i)= S26(j,i) * T26(j,i) + S27(j,i) * U26(j,i) D24(j,i)= S26(j,i) * T27(j,i) + S27(j,i) * V26(j,i) C25(j,i)= S27(j,i) * S28(j,i) + S26(j,i) * U28(j,i) D25(j,i)= S27(j,i) * T28(j,i) + S26(j,i) * V28(j,i) end do end do Conclusions Over the course of the last year, I have had the opportunity to work with over two dozen academic scientific programmers at leading research universities. Their research interests span a broad range of scientific fields. Except for two programs that relied almost exclusively on library routines (matrix multiply and fast Fourier transform), I was able to improve significantly the single processor performance of all codes. Improvements range from 2x to 15.5x with a simple average of 4.75x. Changes to the source code were at a very high level. I did not use sophisticated techniques or programming tools to discover inefficiencies or effect the changes. Only one code was parallel despite the availability of parallel systems to all developers. Clearly, we have a problem—personal scientific research codes are highly inefficient and not running parallel. The developers are unaware of simple optimization techniques to make programs run faster. They lack education in the art of code optimization and parallel programming. I do not believe we can fix the problem by publishing additional books or training manuals. To date, the developers in questions have not studied the books or manual available, and are unlikely to do so in the future. Short courses are a possible solution, but I believe they are too concentrated to be much use. The general concepts can be taught in a three or four day course, but that is not enough time for students to practice what they learn and acquire the experience to apply and extend the concepts to their codes. Practice is the key to becoming proficient at optimization. I recommend that graduate students be required to take a semester length course in optimization and parallel programming. We would never give someone access to state-of-the-art scientific equipment costing hundreds of thousands of dollars without first requiring them to demonstrate that they know how to use the equipment. Yet the criterion for time on state-of-the-art supercomputers is at most an interesting project. Requestors are never asked to demonstrate that they know how to use the system, or can use the system effectively. A semester course would teach them the required skills. Government agencies that fund academic scientific research pay for most of the computer systems supporting scientific research as well as the development of most personal scientific codes. These agencies should require graduate schools to offer a course in optimization and parallel programming as a requirement for funding. About the Author John Feo received his Ph.D. in Computer Science from The University of Texas at Austin in 1986. After graduate school, Dr. Feo worked at Lawrence Livermore National Laboratory where he was the Group Leader of the Computer Research Group and principal investigator of the Sisal Language Project. In 1997, Dr. Feo joined Tera Computer Company where he was project manager for the MTA, and oversaw the programming and evaluation of the MTA at the San Diego Supercomputer Center. In 2000, Dr. Feo joined Sun Microsystems as an HPC application specialist. He works with university research groups to optimize and parallelize scientific codes. Dr. Feo has published over two dozen research articles in the areas of parallel parallel programming, parallel programming languages, and application performance.

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  • Is there an easy way to type in common math symbols?

    - by srcspider
    Disclaimer: I'm sure someone is going to moan about easy-of-use, for the purpose of this question consider readability to be the only factor that matters So I found this site that converts to easting northing, it's not really important what that even means but here's how the piece of javascript looks. /** * Convert Ordnance Survey grid reference easting/northing coordinate to (OSGB36) latitude/longitude * * @param {OsGridRef} gridref - easting/northing to be converted to latitude/longitude * @returns {LatLonE} latitude/longitude (in OSGB36) of supplied grid reference */ OsGridRef.osGridToLatLong = function(gridref) { var E = gridref.easting; var N = gridref.northing; var a = 6377563.396, b = 6356256.909; // Airy 1830 major & minor semi-axes var F0 = 0.9996012717; // NatGrid scale factor on central meridian var f0 = 49*Math.PI/180, ?0 = -2*Math.PI/180; // NatGrid true origin var N0 = -100000, E0 = 400000; // northing & easting of true origin, metres var e2 = 1 - (b*b)/(a*a); // eccentricity squared var n = (a-b)/(a+b), n2 = n*n, n3 = n*n*n; // n, n², n³ var f=f0, M=0; do { f = (N-N0-M)/(a*F0) + f; var Ma = (1 + n + (5/4)*n2 + (5/4)*n3) * (f-f0); var Mb = (3*n + 3*n*n + (21/8)*n3) * Math.sin(f-f0) * Math.cos(f+f0); var Mc = ((15/8)*n2 + (15/8)*n3) * Math.sin(2*(f-f0)) * Math.cos(2*(f+f0)); var Md = (35/24)*n3 * Math.sin(3*(f-f0)) * Math.cos(3*(f+f0)); M = b * F0 * (Ma - Mb + Mc - Md); // meridional arc } while (N-N0-M >= 0.00001); // ie until < 0.01mm var cosf = Math.cos(f), sinf = Math.sin(f); var ? = a*F0/Math.sqrt(1-e2*sinf*sinf); // nu = transverse radius of curvature var ? = a*F0*(1-e2)/Math.pow(1-e2*sinf*sinf, 1.5); // rho = meridional radius of curvature var ?2 = ?/?-1; // eta = ? var tanf = Math.tan(f); var tan2f = tanf*tanf, tan4f = tan2f*tan2f, tan6f = tan4f*tan2f; var secf = 1/cosf; var ?3 = ?*?*?, ?5 = ?3*?*?, ?7 = ?5*?*?; var VII = tanf/(2*?*?); var VIII = tanf/(24*?*?3)*(5+3*tan2f+?2-9*tan2f*?2); var IX = tanf/(720*?*?5)*(61+90*tan2f+45*tan4f); var X = secf/?; var XI = secf/(6*?3)*(?/?+2*tan2f); var XII = secf/(120*?5)*(5+28*tan2f+24*tan4f); var XIIA = secf/(5040*?7)*(61+662*tan2f+1320*tan4f+720*tan6f); var dE = (E-E0), dE2 = dE*dE, dE3 = dE2*dE, dE4 = dE2*dE2, dE5 = dE3*dE2, dE6 = dE4*dE2, dE7 = dE5*dE2; f = f - VII*dE2 + VIII*dE4 - IX*dE6; var ? = ?0 + X*dE - XI*dE3 + XII*dE5 - XIIA*dE7; return new LatLonE(f.toDegrees(), ?.toDegrees(), GeoParams.datum.OSGB36); } I found that to be a really nice way of writing an algorythm, at least as far as redability is concerned. Is there any way to easily write the special symbols. And by easily write I mean NOT copy/paste them.

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