Monthly Archives

Articles indexed in December 2012

Page 113/287 | < Previous Page | 109 110 111 112 113 114 115 116 117 118 119 120  | Next Page >

• Testing a SQL Query for True or False

  - by KickingLettuce

  $sql = "SELECT # FROM users WHERE onduty = 1 AND loc_id = '{$site}';"; $result = mysql_query($sql); I simply want to test if this is true or false. If it returns 0 rows, I want next line to be something like: if (!$result) { //do this; } However, in my test, I am getting false when I know it should be true. Is this sound logic here? (note, yes I know I should be using mysqli_query, that is not what I am asking here)

  Read the article

• How to exclude result from 2 different table and show the result?

  - by Lucy Amalia Lusiana

  I have 2 tables: T1 (Total User) T2 (User_id_that_have_done_something_for_today) the mysql_query result from T1 are (Total User) ----- ID ----- | 1 | | 2 | | 3 | | 4 | | 5 | | 6 | | 7 | | 8 | the mysql_query from T2 are (logged) ----- user_id_log ----- | 1 | | 3 | | 4 | | 7 | How to compare T1 and T2 And only show the user that not approved? The end result that i wanted is (result) ----- ID ----- | 2 | | 5 | | 6 | | 8 | I spent 2 days to make this work but i cannot do it I have try LEFT JOIN and NOT IT but the result is not what i wanted Please help me, thank you

  Read the article

• Rails 3) Delete, Destory, and Routing

  - by Maximus S

  The problem is the code below <%= button_to t('.delete'), @post, :method => :delete, :class => :destroy %> My Post model has many relations that are dependent on delete. However, the code above will only remove the post, leaving its relations intact. The problem is that methods delete and destroy are different in that method delete doesn't instantiate the object. So I need to use "destroy" instead of "delete" my post. <%= button_to t('.delete'), @post, :method => :destroy %> gives me routing error. No route matches [POST] "/posts/2" <%= button_to t('.delete'), @post, Post.destroy(@post) %> deletes the post without clicking the button. Could anyone help me with this? UPDATE: application.js //= require jquery //= require jquery-ui //= require jquery_ujs //= require bootstrap-modal //= require bootstrap-typeahead //= require_tree . rake routes DELETE (/:locale)/posts/:id(.:format) posts#destroy Post model has_many :tag_links, :dependent => :destroy has_many :tags, :through => :tag_links Tag model has_many :tag_links, :dependent => :destroy has_many :posts, :through => :tag_links Problem: When I delete a post, all the tag_links are destroyed but tags still exist.

  Read the article

• Compiling error with API 10

  - by Suhel De Corser

  I was following the basic tutorials on developers.android.com and came by creating the activity named DisplayMessageActivity. It is a blank activity with all the specifications given as shown in the tutorial. FYI, I am using Min SDK = API 8, Target SDK = API 16, Compile with = API 10 The next thing is that there are two errors: "The method getActionBar() is undefined for the type DisplayMessageActivity "home cannot be resolved or is not a field" I tried changing the API to 14 which called for another problem, it wants the minimum API to be 11. That solves these problems, but the main problem is so many devices still use Gingerbread or maybe FroYo. Can't I write for them? Do I have to go higher? How to write for them?

  Read the article

• How to remove "Standard Error" column from xtable() output of an lm on R/RSweave/LaTeX

  - by Lucas Spangher

  I'm currently doing some data analysis on population data, so reporting the standard errors in the tables of parameter coefficients just doesn't really make statistical sense. I've done a fair bit of searching and can't find any way to customize the xtable output to remove it. Can anyone point me in the right direction? Thanks a lot, I didn't post this lightly; if it's something obvious, I apologize for having wasted time!

  Read the article

• extract two parts of a string using regex in php

  - by Jubair

  Ok so I have this string: &lt;img src=images/imagename.gif alt='descriptive text here'&gt; and I am trying to split it up into the following two strings (array of two strings, what ever, just broken up). imagename.gif descriptive text here Note yes, its' actually the & lt; and not < same with the closing on the string. I know regex is the answer, but not the best at regext to know to pull it off in php.

  Read the article

• Get last row of many matrices (ASCII text files) and create a new matrix from these rows

  - by nofunsally

  I have over a thousand matrices (6 x 2000, ASCII files, comma delimited) that I generated from MATLAB. I want to get the last row of each matrix / text file and save them in a new matrix / text file. The text files have crazy names so when I load them I can name them whatever. Right now I would do this to achieve my goal: % A = load('crazyname.txt'); % B = load('crazynameagain.txt'); % C = load('crazynameyetagain.txt'); A = [5 5 5; 5 5 5; 1 1 1]; B = [5 5 5; 5 5 5; 2 2 2]; C = [5 5 5; 5 5 5; 3 3 3]; D(1,:)=A(end,:); D(2,:)=B(end,:); D(3,:)=C(end,:); I will create each command (e.g. load, building D step by step) in Excel by combining text cells to create a command. Is there a better way to do this? Could I load / assign the matrices with a name that would better suit them to be used in a for loop? Or is some other MATLAB command that would facilitate this? Thanks.

  Read the article

• Change cookies when doing jQuery.ajax requests in Chrome Extensions

  - by haskellguy

  I have wrote a plugin for facebook that sends data to testing-fb.local. The request goes through if the user is logged in. Here is the workflow: User logs in from testing-fb.local Cookies are stored When $.ajax() are fired from the Chrome extension Chrome extension listen with chrome.webRequest.onBeforeSendHeaders Chrome extension checks for cookies from chrome.cookies.get Chrome changes the Set-Cookies header to be sent And the request goes through. I wrote this part of code that shoud be this: function getCookies (callback) { chrome.cookies.get({url:"https://testing-fb.local", name: "connect.sid"}, function(a){ return callback(a) }) } chrome.webRequest.onBeforeSendHeaders.addListener( function(details) { getCookies(function(a){ // Here something happens }) }, {urls: ["https://testing-fb.local/*"]}, ['blocking']); Here is my manifest.json: { "name": "test-fb", "version": "1.0", "manifest_version": 1, "description": "testing", "permissions": [ "cookies", "webRequest", "tabs", "http://*/*", "https://*/*" ], "background": { "scripts": ["background.js"] }, "content_scripts": [ { "matches": ["http://*.facebook.com/*", "https://*.facebook.com/*"], "exclude_matches" : [ "*://*.facebook.com/ajax/*", "*://*.channel.facebook.tld/*", "*://*.facebook.tld/pagelet/generic.php/pagelet/home/morestories.php*", "*://*.facebook.tld/ai.php*" ], "js": ["jquery-1.8.3.min.js", "allthefunctions.js"] } ] } In allthefunction.js I have the $.ajax calls, and in background.js is where I put the code above which however looks not to run.. In summary, I have not clear: What I should write in Here something happens If this strategy is going to work Where should I put this code?

  Read the article

• Why do some Flask session values disappear from the session after closing the browser window, but then reappear later without me adding them?

  - by Ben

  So my understanding of Flask sessions is that I can use it like a dictionary and add values to a session by doing: session['key name'] = 'some value here' And that works fine. On a route I have the client call using AJAX post, I assign a value to the session. And it works fine. I can click on various pages of my site and the value stays in the session. If I close the browser window however, and then go back to my site, the session value I had in there is gone. So that's weird and you would think the problem is the session isn't permanent. I also implemented Flask-Openid and that uses the session to store information and that does persist if I close the browser window and open it back up again. I also checked the cookie after closing the browser window, but before going back to my site, and the cookie is indeed still there. Another odd piece of behaviour (which may be related) is that some values I have written to the session for testing purposes will go away when I access the AJAX post route and assign the correct value. So that is odd, but what is truly weird is that when I then close the browser window and open it up again, and have thus lost the value I was trying to retain, the ones that I lost previously actually return! They aren't being reassigned because there's no code in my Python files to reassign those values. Here is some outputs to helper make it clearer. They are all outputed from a route for a real page, and not the AJAX post route I mentioned above. This is the output after I have assigned the value I want to store in the session. The value key is 'userid' - all the other values are dummy ones I have added in trying to solve this problem. 'userid': 8 will stay in the session as long as I don't close the browser window. I can access other routes and the value will stay there just like it should. ['session.=', <SecureCookieSession {'userid': 8, 'test_variable_num': 102, 'adding using before request': 'hi', '_permanent': True, 'test_variable_text': 'hi!'}>] If I do close the browser window, and go back into the site, but without redoing the AJAX post request, I get this output: ['session.=', <SecureCookieSession {'adding using before request': 'hi', '_permanent': True, 'yo': 'yo'}>] The 'yo' value was not in the first first output. I don't know where it came from. I searched my code for 'yo' and there is no instances of me assigning that value anywhere. I think I may have added it to the session days ago. So it seems like it is persisting, but being hidden when the other values are written. And this last one is me accessing the AJAX post route again, and then going to the page that prints out the keys using debug. Same output as the first output I pasted above, which you would expect, and the 'yo' value is gone again (but it will come back if I close the browser window) ['session.=', <SecureCookieSession {'userid': 8, 'test_variable_num': 102, 'adding using before request': 'hi', '_permanent': True, 'test_variable_text': 'hi!'}>] I tested this in both Chrome and Firefox. So I find this all weird and I am guessing it stems from a misunderstanding of how sessions work. I think they're dictionaries and I can write dictionary values into them and retrieve them days later as long as I set the session to permanent and the cookie doesn't get deleted. Any ideas why this weird behaviour is happening?

  Read the article

• Change English numbers to Persian and vice versa in MVC (httpmodule)?

  - by Mohammad

  I wanna change all English numbers to Persian for showing to users. and change them to English numbers again for giving all requests (Postbacks) e.g: we have something like this in view IRQ170, I wanna show IRQ??? to users and give IRQ170 from users. I know, I have to use Httpmodule, But I don't know how ? Could you please guide me? Edit : Let me describe more : I've written the following http module : using System; using System.Collections.Specialized; using System.Diagnostics; using System.IO; using System.Text; using System.Text.RegularExpressions; using System.Web; using System.Web.UI; using Smartiz.Common; namespace Smartiz.UI.Classes { public class PersianNumberModule : IHttpModule { private StreamWatcher _watcher; #region Implementation of IHttpModule /// <summary> /// Initializes a module and prepares it to handle requests. /// </summary> /// <param name="context">An <see cref="T:System.Web.HttpApplication"/> that provides access to the methods, properties, and events common to all application objects within an ASP.NET application </param> public void Init(HttpApplication context) { context.BeginRequest += ContextBeginRequest; context.EndRequest += ContextEndRequest; } /// <summary> /// Disposes of the resources (other than memory) used by the module that implements <see cref="T:System.Web.IHttpModule"/>. /// </summary> public void Dispose() { } #endregion private void ContextBeginRequest(object sender, EventArgs e) { HttpApplication context = sender as HttpApplication; if (context == null) return; _watcher = new StreamWatcher(context.Response.Filter); context.Response.Filter = _watcher; } private void ContextEndRequest(object sender, EventArgs e) { HttpApplication context = sender as HttpApplication; if (context == null) return; _watcher = new StreamWatcher(context.Response.Filter); context.Response.Filter = _watcher; } } public class StreamWatcher : Stream { private readonly Stream _stream; private readonly MemoryStream _memoryStream = new MemoryStream(); public StreamWatcher(Stream stream) { _stream = stream; } public override void Flush() { _stream.Flush(); } public override int Read(byte[] buffer, int offset, int count) { int bytesRead = _stream.Read(buffer, offset, count); string orgContent = Encoding.UTF8.GetString(buffer, offset, bytesRead); string newContent = orgContent.ToEnglishNumber(); int newByteCountLength = Encoding.UTF8.GetByteCount(newContent); Encoding.UTF8.GetBytes(newContent, 0, Encoding.UTF8.GetByteCount(newContent), buffer, 0); return newByteCountLength; } public override void Write(byte[] buffer, int offset, int count) { string strBuffer = Encoding.UTF8.GetString(buffer, offset, count); MatchCollection htmlAttributes = Regex.Matches(strBuffer, @"(\S+)=[""']?((?:.(?![""']?\s+(?:\S+)=|[>""']))+.)[""']?", RegexOptions.IgnoreCase | RegexOptions.Multiline); foreach (Match match in htmlAttributes) { strBuffer = strBuffer.Replace(match.Value, match.Value.ToEnglishNumber()); } MatchCollection scripts = Regex.Matches(strBuffer, "<script[^>]*>(.*?)</script>", RegexOptions.Singleline | RegexOptions.IgnoreCase | RegexOptions.Multiline | RegexOptions.IgnorePatternWhitespace); foreach (Match match in scripts) { MatchCollection values = Regex.Matches(match.Value, @"([""'])(?:(?=(\\?))\2.)*?\1", RegexOptions.Singleline | RegexOptions.IgnoreCase | RegexOptions.Multiline | RegexOptions.IgnorePatternWhitespace); foreach (Match stringValue in values) { strBuffer = strBuffer.Replace(stringValue.Value, stringValue.Value.ToEnglishNumber()); } } MatchCollection styles = Regex.Matches(strBuffer, "<style[^>]*>(.*?)</style>", RegexOptions.Singleline | RegexOptions.IgnoreCase | RegexOptions.Multiline | RegexOptions.IgnorePatternWhitespace); foreach (Match match in styles) { strBuffer = strBuffer.Replace(match.Value, match.Value.ToEnglishNumber()); } byte[] data = Encoding.UTF8.GetBytes(strBuffer); _memoryStream.Write(data, offset, count); _stream.Write(data, offset, count); } public override string ToString() { return Encoding.UTF8.GetString(_memoryStream.ToArray()); } #region Rest of the overrides public override bool CanRead { get { throw new NotImplementedException(); } } public override bool CanSeek { get { throw new NotImplementedException(); } } public override bool CanWrite { get { throw new NotImplementedException(); } } public override long Seek(long offset, SeekOrigin origin) { throw new NotImplementedException(); } public override void SetLength(long value) { throw new NotImplementedException(); } public override long Length { get { throw new NotImplementedException(); } } public override long Position { get { throw new NotImplementedException(); } set { throw new NotImplementedException(); } } #endregion } } It works well, but It converts all numbers in css and scripts files to Persian and it causes error.

  Read the article

• Create alphabetical Pagination in wordpress

  - by user1870689

  I need to display list of names with alphabetical pagination in wordpress. Example.... when B is selected.. A B C D...X Y Z Bassil | Bastien | Belta | Billy | Bynoo and when i click A, i need only names starting with A... I found this code on PasteBin ... but it create the full list, I need all letters to appear like A B C D ..... X Y Z ........... and only display names with starting letter selected...

  Read the article

• Window sizing constraints by content

  - by EFraim

  I want the window to respect MinWidth/MinHeight and MaxWidth/MaxHeight specifications of the content control inside. Some suggested using SizeToContent, but this only helps to set the initial window size, not the constraints. Others suggested overriding MeasureOverride and setting window's Min/Max height and width there, but this seems to be somewhat unclean, considering that such a trivial problem should surely have a purely declarative solution. Just to mention another solution which seems reasonable but does not work (and had been previously mentioned in an answer which got deleted): binding MinWidth of the window to MinWidth of the control does not take into account window decorations.

  Read the article

• Eager Loading more than 1 table in LinqtoSql

  - by Michael Freidgeim

  When I've tried in Linq2Sql to load table with 2 child tables, I've noticed, that multiple SQLs are generated. I've found that  it isa known issue, if you try to specify more than one to pre-load it just  picks which one to pre-load and which others to leave deferred (simply ignoring those LoadWith hints)There are more explanations in http://codebetter.com/blogs/david.hayden/archive/2007/08/06/linq-to-sql-query-tuning-appears-to-break-down-in-more-advanced-scenarios.aspxThe reason the relationship in your blog post above is generating multiple queries is that you have two (1:n) relationship (Customers->Orders) and (Orders->OrderDetails). If you just had one (1:n) relationship (Customer->Orders) or (Orders->OrderDetails) LINQ to SQL would optimize and grab it in one query (using a JOIN).  The alternative -to use SQL and POCO classes-see http://stackoverflow.com/questions/238504/linq-to-sql-loading-child-entities-without-using-dataloadoptions?rq=1Fortunately the problem is not applicable to Entity Framework, that we want to use in future development instead of Linq2SqlProduct firstProduct = db.Product.Include("OrderDetail").Include("Supplier").First(); ?

  Read the article

• A Taxonomy of Numerical Methods v1

  - by JoshReuben

  Numerical Analysis – When, What, (but not how) Once you understand the Math & know C++, Numerical Methods are basically blocks of iterative & conditional math code. I found the real trick was seeing the forest for the trees – knowing which method to use for which situation. Its pretty easy to get lost in the details – so I’ve tried to organize these methods in a way that I can quickly look this up. I’ve included links to detailed explanations and to C++ code examples. I’ve tried to classify Numerical methods in the following broad categories: Solving Systems of Linear Equations Solving Non-Linear Equations Iteratively Interpolation Curve Fitting Optimization Numerical Differentiation & Integration Solving ODEs Boundary Problems Solving EigenValue problems Enjoy – I did ! Solving Systems of Linear Equations Overview Solve sets of algebraic equations with x unknowns The set is commonly in matrix form Gauss-Jordan Elimination http://en.wikipedia.org/wiki/Gauss%E2%80%93Jordan_elimination C++: http://www.codekeep.net/snippets/623f1923-e03c-4636-8c92-c9dc7aa0d3c0.aspx Produces solution of the equations & the coefficient matrix Efficient, stable 2 steps: · Forward Elimination – matrix decomposition: reduce set to triangular form (0s below the diagonal) or row echelon form. If degenerate, then there is no solution · Backward Elimination –write the original matrix as the product of ints inverse matrix & its reduced row-echelon matrix à reduce set to row canonical form & use back-substitution to find the solution to the set Elementary ops for matrix decomposition: · Row multiplication · Row switching · Add multiples of rows to other rows Use pivoting to ensure rows are ordered for achieving triangular form LU Decomposition http://en.wikipedia.org/wiki/LU_decomposition C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-lu-decomposition-for-solving.html Represent the matrix as a product of lower & upper triangular matrices A modified version of GJ Elimination Advantage – can easily apply forward & backward elimination to solve triangular matrices Techniques: · Doolittle Method – sets the L matrix diagonal to unity · Crout Method - sets the U matrix diagonal to unity Note: both the L & U matrices share the same unity diagonal & can be stored compactly in the same matrix Gauss-Seidel Iteration http://en.wikipedia.org/wiki/Gauss%E2%80%93Seidel_method C++: http://www.nr.com/forum/showthread.php?t=722 Transform the linear set of equations into a single equation & then use numerical integration (as integration formulas have Sums, it is implemented iteratively). an optimization of Gauss-Jacobi: 1.5 times faster, requires 0.25 iterations to achieve the same tolerance Solving Non-Linear Equations Iteratively find roots of polynomials – there may be 0, 1 or n solutions for an n order polynomial use iterative techniques Iterative methods · used when there are no known analytical techniques · Requires set functions to be continuous & differentiable · Requires an initial seed value – choice is critical to convergence à conduct multiple runs with different starting points & then select best result · Systematic - iterate until diminishing returns, tolerance or max iteration conditions are met · bracketing techniques will always yield convergent solutions, non-bracketing methods may fail to converge Incremental method if a nonlinear function has opposite signs at 2 ends of a small interval x1 & x2, then there is likely to be a solution in their interval – solutions are detected by evaluating a function over interval steps, for a change in sign, adjusting the step size dynamically. Limitations – can miss closely spaced solutions in large intervals, cannot detect degenerate (coinciding) solutions, limited to functions that cross the x-axis, gives false positives for singularities Fixed point method http://en.wikipedia.org/wiki/Fixed-point_iteration C++: http://books.google.co.il/books?id=weYj75E_t6MC&pg=PA79&lpg=PA79&dq=fixed+point+method++c%2B%2B&source=bl&ots=LQ-5P_taoC&sig=lENUUIYBK53tZtTwNfHLy5PEWDk&hl=en&sa=X&ei=wezDUPW1J5DptQaMsIHQCw&redir_esc=y#v=onepage&q=fixed%20point%20method%20%20c%2B%2B&f=false Algebraically rearrange a solution to isolate a variable then apply incremental method Bisection method http://en.wikipedia.org/wiki/Bisection_method C++: http://numericalcomputing.wordpress.com/category/algorithms/ Bracketed - Select an initial interval, keep bisecting it ad midpoint into sub-intervals and then apply incremental method on smaller & smaller intervals – zoom in Adv: unaffected by function gradient à reliable Disadv: slow convergence False Position Method http://en.wikipedia.org/wiki/False_position_method C++: http://www.dreamincode.net/forums/topic/126100-bisection-and-false-position-methods/ Bracketed - Select an initial interval , & use the relative value of function at interval end points to select next sub-intervals (estimate how far between the end points the solution might be & subdivide based on this) Newton-Raphson method http://en.wikipedia.org/wiki/Newton's_method C++: http://www-users.cselabs.umn.edu/classes/Summer-2012/csci1113/index.php?page=./newt3 Also known as Newton's method Convenient, efficient Not bracketed – only a single initial guess is required to start iteration – requires an analytical expression for the first derivative of the function as input. Evaluates the function & its derivative at each step. Can be extended to the Newton MutiRoot method for solving multiple roots Can be easily applied to an of n-coupled set of non-linear equations – conduct a Taylor Series expansion of a function, dropping terms of order n, rewrite as a Jacobian matrix of PDs & convert to simultaneous linear equations !!! Secant Method http://en.wikipedia.org/wiki/Secant_method C++: http://forum.vcoderz.com/showthread.php?p=205230 Unlike N-R, can estimate first derivative from an initial interval (does not require root to be bracketed) instead of inputting it Since derivative is approximated, may converge slower. Is fast in practice as it does not have to evaluate the derivative at each step. Similar implementation to False Positive method Birge-Vieta Method http://mat.iitm.ac.in/home/sryedida/public_html/caimna/transcendental/polynomial%20methods/bv%20method.html C++: http://books.google.co.il/books?id=cL1boM2uyQwC&pg=SA3-PA51&lpg=SA3-PA51&dq=Birge-Vieta+Method+c%2B%2B&source=bl&ots=QZmnDTK3rC&sig=BPNcHHbpR_DKVoZXrLi4nVXD-gg&hl=en&sa=X&ei=R-_DUK2iNIjzsgbE5ID4Dg&redir_esc=y#v=onepage&q=Birge-Vieta%20Method%20c%2B%2B&f=false combines Horner's method of polynomial evaluation (transforming into lesser degree polynomials that are more computationally efficient to process) with Newton-Raphson to provide a computational speed-up Interpolation Overview Construct new data points for as close as possible fit within range of a discrete set of known points (that were obtained via sampling, experimentation) Use Taylor Series Expansion of a function f(x) around a specific value for x Linear Interpolation http://en.wikipedia.org/wiki/Linear_interpolation C++: http://www.hamaluik.com/?p=289 Straight line between 2 points à concatenate interpolants between each pair of data points Bilinear Interpolation http://en.wikipedia.org/wiki/Bilinear_interpolation C++: http://supercomputingblog.com/graphics/coding-bilinear-interpolation/2/ Extension of the linear function for interpolating functions of 2 variables – perform linear interpolation first in 1 direction, then in another. Used in image processing – e.g. texture mapping filter. Uses 4 vertices to interpolate a value within a unit cell. Lagrange Interpolation http://en.wikipedia.org/wiki/Lagrange_polynomial C++: http://www.codecogs.com/code/maths/approximation/interpolation/lagrange.php For polynomials Requires recomputation for all terms for each distinct x value – can only be applied for small number of nodes Numerically unstable Barycentric Interpolation http://epubs.siam.org/doi/pdf/10.1137/S0036144502417715 C++: http://www.gamedev.net/topic/621445-barycentric-coordinates-c-code-check/ Rearrange the terms in the equation of the Legrange interpolation by defining weight functions that are independent of the interpolated value of x Newton Divided Difference Interpolation http://en.wikipedia.org/wiki/Newton_polynomial C++: http://jee-appy.blogspot.co.il/2011/12/newton-divided-difference-interpolation.html Hermite Divided Differences: Interpolation polynomial approximation for a given set of data points in the NR form - divided differences are used to approximately calculate the various differences. For a given set of 3 data points , fit a quadratic interpolant through the data Bracketed functions allow Newton divided differences to be calculated recursively Difference table Cubic Spline Interpolation http://en.wikipedia.org/wiki/Spline_interpolation C++: https://www.marcusbannerman.co.uk/index.php/home/latestarticles/42-articles/96-cubic-spline-class.html Spline is a piecewise polynomial Provides smoothness – for interpolations with significantly varying data Use weighted coefficients to bend the function to be smooth & its 1st & 2nd derivatives are continuous through the edge points in the interval Curve Fitting A generalization of interpolating whereby given data points may contain noise à the curve does not necessarily pass through all the points Least Squares Fit http://en.wikipedia.org/wiki/Least_squares C++: http://www.ccas.ru/mmes/educat/lab04k/02/least-squares.c Residual – difference between observed value & expected value Model function is often chosen as a linear combination of the specified functions Determines: A) The model instance in which the sum of squared residuals has the least value B) param values for which model best fits data Straight Line Fit Linear correlation between independent variable and dependent variable Linear Regression http://en.wikipedia.org/wiki/Linear_regression C++: http://www.oocities.org/david_swaim/cpp/linregc.htm Special case of statistically exact extrapolation Leverage least squares Given a basis function, the sum of the residuals is determined and the corresponding gradient equation is expressed as a set of normal linear equations in matrix form that can be solved (e.g. using LU Decomposition) Can be weighted - Drop the assumption that all errors have the same significance –-> confidence of accuracy is different for each data point. Fit the function closer to points with higher weights Polynomial Fit - use a polynomial basis function Moving Average http://en.wikipedia.org/wiki/Moving_average C++: http://www.codeproject.com/Articles/17860/A-Simple-Moving-Average-Algorithm Used for smoothing (cancel fluctuations to highlight longer-term trends & cycles), time series data analysis, signal processing filters Replace each data point with average of neighbors. Can be simple (SMA), weighted (WMA), exponential (EMA). Lags behind latest data points – extra weight can be given to more recent data points. Weights can decrease arithmetically or exponentially according to distance from point. Parameters: smoothing factor, period, weight basis Optimization Overview Given function with multiple variables, find Min (or max by minimizing –f(x)) Iterative approach Efficient, but not necessarily reliable Conditions: noisy data, constraints, non-linear models Detection via sign of first derivative - Derivative of saddle points will be 0 Local minima Bisection method Similar method for finding a root for a non-linear equation Start with an interval that contains a minimum Golden Search method http://en.wikipedia.org/wiki/Golden_section_search C++: http://www.codecogs.com/code/maths/optimization/golden.php Bisect intervals according to golden ratio 0.618.. Achieves reduction by evaluating a single function instead of 2 Newton-Raphson Method Brent method http://en.wikipedia.org/wiki/Brent's_method C++: http://people.sc.fsu.edu/~jburkardt/cpp_src/brent/brent.cpp Based on quadratic or parabolic interpolation – if the function is smooth & parabolic near to the minimum, then a parabola fitted through any 3 points should approximate the minima – fails when the 3 points are collinear , in which case the denominator is 0 Simplex Method http://en.wikipedia.org/wiki/Simplex_algorithm C++: http://www.codeguru.com/cpp/article.php/c17505/Simplex-Optimization-Algorithm-and-Implemetation-in-C-Programming.htm Find the global minima of any multi-variable function Direct search – no derivatives required At each step it maintains a non-degenerative simplex – a convex hull of n+1 vertices. Obtains the minimum for a function with n variables by evaluating the function at n-1 points, iteratively replacing the point of worst result with the point of best result, shrinking the multidimensional simplex around the best point. Point replacement involves expanding & contracting the simplex near the worst value point to determine a better replacement point Oscillation can be avoided by choosing the 2nd worst result Restart if it gets stuck Parameters: contraction & expansion factors Simulated Annealing http://en.wikipedia.org/wiki/Simulated_annealing C++: http://code.google.com/p/cppsimulatedannealing/ Analogy to heating & cooling metal to strengthen its structure Stochastic method – apply random permutation search for global minima - Avoid entrapment in local minima via hill climbing Heating schedule - Annealing schedule params: temperature, iterations at each temp, temperature delta Cooling schedule – can be linear, step-wise or exponential Differential Evolution http://en.wikipedia.org/wiki/Differential_evolution C++: http://www.amichel.com/de/doc/html/ More advanced stochastic methods analogous to biological processes: Genetic algorithms, evolution strategies Parallel direct search method against multiple discrete or continuous variables Initial population of variable vectors chosen randomly – if weighted difference vector of 2 vectors yields a lower objective function value then it replaces the comparison vector Many params: #parents, #variables, step size, crossover constant etc Convergence is slow – many more function evaluations than simulated annealing Numerical Differentiation Overview 2 approaches to finite difference methods: · A) approximate function via polynomial interpolation then differentiate · B) Taylor series approximation – additionally provides error estimate Finite Difference methods http://en.wikipedia.org/wiki/Finite_difference_method C++: http://www.wpi.edu/Pubs/ETD/Available/etd-051807-164436/unrestricted/EAMPADU.pdf Find differences between high order derivative values - Approximate differential equations by finite differences at evenly spaced data points Based on forward & backward Taylor series expansion of f(x) about x plus or minus multiples of delta h. Forward / backward difference - the sums of the series contains even derivatives and the difference of the series contains odd derivatives – coupled equations that can be solved. Provide an approximation of the derivative within a O(h^2) accuracy There is also central difference & extended central difference which has a O(h^4) accuracy Richardson Extrapolation http://en.wikipedia.org/wiki/Richardson_extrapolation C++: http://mathscoding.blogspot.co.il/2012/02/introduction-richardson-extrapolation.html A sequence acceleration method applied to finite differences Fast convergence, high accuracy O(h^4) Derivatives via Interpolation Cannot apply Finite Difference method to discrete data points at uneven intervals – so need to approximate the derivative of f(x) using the derivative of the interpolant via 3 point Lagrange Interpolation Note: the higher the order of the derivative, the lower the approximation precision Numerical Integration Estimate finite & infinite integrals of functions More accurate procedure than numerical differentiation Use when it is not possible to obtain an integral of a function analytically or when the function is not given, only the data points are Newton Cotes Methods http://en.wikipedia.org/wiki/Newton%E2%80%93Cotes_formulas C++: http://www.siafoo.net/snippet/324 For equally spaced data points Computationally easy – based on local interpolation of n rectangular strip areas that is piecewise fitted to a polynomial to get the sum total area Evaluate the integrand at n+1 evenly spaced points – approximate definite integral by Sum Weights are derived from Lagrange Basis polynomials Leverage Trapezoidal Rule for default 2nd formulas, Simpson 1/3 Rule for substituting 3 point formulas, Simpson 3/8 Rule for 4 point formulas. For 4 point formulas use Bodes Rule. Higher orders obtain more accurate results Trapezoidal Rule uses simple area, Simpsons Rule replaces the integrand f(x) with a quadratic polynomial p(x) that uses the same values as f(x) for its end points, but adds a midpoint Romberg Integration http://en.wikipedia.org/wiki/Romberg's_method C++: http://code.google.com/p/romberg-integration/downloads/detail?name=romberg.cpp&can=2&q= Combines trapezoidal rule with Richardson Extrapolation Evaluates the integrand at equally spaced points The integrand must have continuous derivatives Each R(n,m) extrapolation uses a higher order integrand polynomial replacement rule (zeroth starts with trapezoidal) à a lower triangular matrix set of equation coefficients where the bottom right term has the most accurate approximation. The process continues until the difference between 2 successive diagonal terms becomes sufficiently small. Gaussian Quadrature http://en.wikipedia.org/wiki/Gaussian_quadrature C++: http://www.alglib.net/integration/gaussianquadratures.php Data points are chosen to yield best possible accuracy – requires fewer evaluations Ability to handle singularities, functions that are difficult to evaluate The integrand can include a weighting function determined by a set of orthogonal polynomials. Points & weights are selected so that the integrand yields the exact integral if f(x) is a polynomial of degree <= 2n+1 Techniques (basically different weighting functions): · Gauss-Legendre Integration w(x)=1 · Gauss-Laguerre Integration w(x)=e^-x · Gauss-Hermite Integration w(x)=e^-x^2 · Gauss-Chebyshev Integration w(x)= 1 / Sqrt(1-x^2) Solving ODEs Use when high order differential equations cannot be solved analytically Evaluated under boundary conditions RK for systems – a high order differential equation can always be transformed into a coupled first order system of equations Euler method http://en.wikipedia.org/wiki/Euler_method C++: http://rosettacode.org/wiki/Euler_method First order Runge–Kutta method. Simple recursive method – given an initial value, calculate derivative deltas. Unstable & not very accurate (O(h) error) – not used in practice A first-order method - the local error (truncation error per step) is proportional to the square of the step size, and the global error (error at a given time) is proportional to the step size In evolving solution between data points xn & xn+1, only evaluates derivatives at beginning of interval xn à asymmetric at boundaries Higher order Runge Kutta http://en.wikipedia.org/wiki/Runge%E2%80%93Kutta_methods C++: http://www.dreamincode.net/code/snippet1441.htm 2nd & 4th order RK - Introduces parameterized midpoints for more symmetric solutions à accuracy at higher computational cost Adaptive RK – RK-Fehlberg – estimate the truncation at each integration step & automatically adjust the step size to keep error within prescribed limits. At each step 2 approximations are compared – if in disagreement to a specific accuracy, the step size is reduced Boundary Value Problems Where solution of differential equations are located at 2 different values of the independent variable x à more difficult, because cannot just start at point of initial value – there may not be enough starting conditions available at the end points to produce a unique solution An n-order equation will require n boundary conditions – need to determine the missing n-1 conditions which cause the given conditions at the other boundary to be satisfied Shooting Method http://en.wikipedia.org/wiki/Shooting_method C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-shooting-method-for-solving.html Iteratively guess the missing values for one end & integrate, then inspect the discrepancy with the boundary values of the other end to adjust the estimate Given the starting boundary values u1 & u2 which contain the root u, solve u given the false position method (solving the differential equation as an initial value problem via 4th order RK), then use u to solve the differential equations. Finite Difference Method For linear & non-linear systems Higher order derivatives require more computational steps – some combinations for boundary conditions may not work though Improve the accuracy by increasing the number of mesh points Solving EigenValue Problems An eigenvalue can substitute a matrix when doing matrix multiplication à convert matrix multiplication into a polynomial EigenValue For a given set of equations in matrix form, determine what are the solution eigenvalue & eigenvectors Similar Matrices - have same eigenvalues. Use orthogonal similarity transforms to reduce a matrix to diagonal form from which eigenvalue(s) & eigenvectors can be computed iteratively Jacobi method http://en.wikipedia.org/wiki/Jacobi_method C++: http://people.sc.fsu.edu/~jburkardt/classes/acs2_2008/openmp/jacobi/jacobi.html Robust but Computationally intense – use for small matrices < 10x10 Power Iteration http://en.wikipedia.org/wiki/Power_iteration For any given real symmetric matrix, generate the largest single eigenvalue & its eigenvectors Simplest method – does not compute matrix decomposition à suitable for large, sparse matrices Inverse Iteration Variation of power iteration method – generates the smallest eigenvalue from the inverse matrix Rayleigh Method http://en.wikipedia.org/wiki/Rayleigh's_method_of_dimensional_analysis Variation of power iteration method Rayleigh Quotient Method Variation of inverse iteration method Matrix Tri-diagonalization Method Use householder algorithm to reduce an NxN symmetric matrix to a tridiagonal real symmetric matrix vua N-2 orthogonal transforms     Whats Next Outside of Numerical Methods there are lots of different types of algorithms that I’ve learned over the decades: Data Mining – (I covered this briefly in a previous post: http://geekswithblogs.net/JoshReuben/archive/2007/12/31/ssas-dm-algorithms.aspx ) Search & Sort Routing Problem Solving Logical Theorem Proving Planning Probabilistic Reasoning Machine Learning Solvers (eg MIP) Bioinformatics (Sequence Alignment, Protein Folding) Quant Finance (I read Wilmott’s books – interesting) Sooner or later, I’ll cover the above topics as well.

  Read the article

• Do NOT Change "Copy Local” project references to false, unless understand subsequences.

  - by Michael Freidgeim

  To optimize performance of visual studio build I've found multiple recommendations to change CopyLocal property for dependent dlls to false,e.g. From http://stackoverflow.com/questions/690033/best-practices-for-large-solutions-in-visual-studio-2008 CopyLocal? For sure turn this offhttp://stackoverflow.com/questions/280751/what-is-the-best-practice-for-copy-local-and-with-project-referencesAlways set the Copy Local property to false and enforce this via a custom msbuild stephttp://codebetter.com/patricksmacchia/2007/06/20/benefit-from-the-c-and-vb-net-compilers-perf/BenefitBenefitMy advice is to always set ‘Copy Local’ to falseSome time ago we've tried to change the setting to false, and found that it causes problem for deployment of top-level projects.Recently I've followed the suggestion and changed the settings for middle-level projects. It didn't cause immediate issues, but I was warned by Readify Consultant Colin Savage about possible errors during deploymentsI haven't undone the changes immediately and we found a few issues during testing.There are many scenarios, when you need to have Copy Local’ left to True.The concerns are highlighted in some stack overflow answers, but they have small number of votes.Top-level projects:  set copy local = true.First of all, it doesn't work correctly for top-level projects, i.e. executables or web sites.As pointed in the answer http://stackoverflow.com/a/6529461/52277for all the references in the one at the top set copy local = true.Alternatively you have to change output directory as it's described in http://www.simple-talk.com/dotnet/.net-framework/partitioning-your-code-base-through-.net-assemblies-and-visual-studio-projects/If you set ‘ Copy Local = false’, VS will, unless you tell it otherwise, place each assembly alone in its own .\bin\Debugdirectory. Because of this, you will need to configure VS to place assemblies together in the same directory. To do so, for each VS project, go to VS > Project Properties > Build tab > Output path, and set the Ouput path to ..\bin\Debugfor debug configuration, and ..\bin\Release for release configuration.Second-level  dependencies:  set copy local = true.Another example when copylocal =false fails on run-time, is when top level assembly doesn't directly referenced one of indirect dependencies.E..g. Top-level assembly A has reference to assembly B with copylocal =true, but assembly B has reference to assembly C with copylocal =false. Most likely assembly C will be missing on runtime and will cause errors E.g. http://stackoverflow.com/questions/602765/when-should-copy-local-be-set-to-true-and-when-should-it-not?lq=1Copy local is important for deployment scenarios and tools. As a general rule you should use CopyLocal=True and http://stackoverflow.com/questions/602765/when-should-copy-local-be-set-to-true-and-when-should-it-not?lq=1 Unfortunately there are some quirks and CopyLocal won't necessary work as expected for assembly references in secondary assemblies structured as shown below.MainApp.exe MyLibrary.dll ThirdPartyLibrary.dll (if in the GAC CopyLocal won't copy to MainApp bin folder)This makes xcopy deployments difficult . .Reflection called DLLs  dependencies:  set copy local = true.E.g user can see error "ISystem.Reflection.ReflectionTypeLoadException: Unable to load one or more of the requested types. Retrieve the LoaderExceptions property for more information."The fix for the issue is recommended in http://stackoverflow.com/a/6200173/52277"I solved this issue by setting the Copy Local attribute of my project's references to true."In general, the problems with investigation of deployment issues may overweight the benefits of reduced build time. Setting the Copy Local to false without considering deployment issues is not a good idea.

  Read the article

• Intellitrace bug causes &ldquo;Operation could destabilize the runtime&rdquo; exception

  - by Magnus Karlsson

  We cant use it when we use simplemembership to handle external authorizations.   Server Error in '/' Application. Operation could destabilize the runtime. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.Security.VerificationException: Operation could destabilize the runtime. Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Stack Trace: [VerificationException: Operation could destabilize the runtime.] DotNetOpenAuth.OpenId.Messages.IndirectSignedResponse.GetSignedMessageParts(Channel channel) +943 DotNetOpenAuth.OpenId.ChannelElements.ExtensionsBindingElement.GetExtensionsDictionary(IProtocolMessage message, Boolean ignoreUnsigned) +282 DotNetOpenAuth.OpenId.ChannelElements.<GetExtensions>d__a.MoveNext() +279 DotNetOpenAuth.OpenId.ChannelElements.ExtensionsBindingElement.ProcessIncomingMessage(IProtocolMessage message) +594 DotNetOpenAuth.Messaging.Channel.ProcessIncomingMessage(IProtocolMessage message) +933 DotNetOpenAuth.OpenId.ChannelElements.OpenIdChannel.ProcessIncomingMessage(IProtocolMessage message) +326 DotNetOpenAuth.Messaging.Channel.ReadFromRequest(HttpRequestBase httpRequest) +1343 DotNetOpenAuth.OpenId.RelyingParty.OpenIdRelyingParty.GetResponse(HttpRequestBase httpRequestInfo) +241 DotNetOpenAuth.OpenId.RelyingParty.OpenIdRelyingParty.GetResponse() +361 DotNetOpenAuth.AspNet.Clients.OpenIdClient.VerifyAuthentication(HttpContextBase context) +136 DotNetOpenAuth.AspNet.OpenAuthSecurityManager.VerifyAuthentication(String returnUrl) +984 Microsoft.Web.WebPages.OAuth.OAuthWebSecurity.VerifyAuthenticationCore(HttpContextBase context, String returnUrl) +333 Microsoft.Web.WebPages.OAuth.OAuthWebSecurity.VerifyAuthentication(String returnUrl) +192 PrioMvcWebRole.Controllers.AccountController.ExternalLoginCallback(String returnUrl) in c:hiddenforyou lambda_method(Closure , ControllerBase , Object[] ) +127 System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters) +250 System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +39 System.Web.Mvc.Async.<>c__DisplayClass39.<BeginInvokeActionMethodWithFilters>b__33() +87 System.Web.Mvc.Async.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49() +439 System.Web.Mvc.Async.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49() +439 System.Web.Mvc.Async.<>c__DisplayClass37.<BeginInvokeActionMethodWithFilters>b__36(IAsyncResult asyncResult) +15 System.Web.Mvc.Async.<>c__DisplayClass2a.<BeginInvokeAction>b__20() +34 System.Web.Mvc.Async.<>c__DisplayClass25.<BeginInvokeAction>b__22(IAsyncResult asyncResult) +221 System.Web.Mvc.<>c__DisplayClass1d.<BeginExecuteCore>b__18(IAsyncResult asyncResult) +28 System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +15 System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +42 System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +15 System.Web.Mvc.<>c__DisplayClass8.<BeginProcessRequest>b__3(IAsyncResult asyncResult) +42 System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +15 System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +523 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +176 Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.17929

  Read the article

• ZFS/Btrfs/LVM2-like storage with advanced features on Linux?

  - by Easter Sunshine

  I have 3 identical internal 7200 RPM SATA hard disk drives on a Linux machine. I'm looking for a storage set-up that will give me all of this: Different data sets (filesystems or subtrees) can have different RAID levels so I can choose performance, space overhead, and risk trade-offs differently for different data sets while having a few number of physical disks (very important data can be 3xRAID1, important data can be 3xRAID5, unimportant reproducible data can be 3xRAID0). If each data set has an explicit size or size limit, then the ability to grow and shrink the size limit (offline if need be) Avoid out-of-kernel modules R/W or read-only COW snapshots. If it's a block-level snapshots, the filesystem should be synced and quiesced during a snapshot. Ability to add physical disks and then grow/redistribute RAID1, RAID5, and RAID0 volumes to take advantage of the new spindle and make sure no spindle is hotter than the rest (e.g., in NetApp, growing a RAID-DP raid group by a few disks will not balance the I/O across them without an explicit redistribution) Not required but nice-to-haves: Transparent compression, per-file or subtree. Even better if, like NetApps, analyzes the data first for compressibility and only compresses compressible data Deduplication that doesn't have huge performance penalties or require obscene amounts of memory (NetApp does scheduled deduplication on weekends, which is good) Resistance to silent data corruption like ZFS (this is not required because I have never seen ZFS report any data corruption on these specific disks) Storage tiering, either automatic (based on caching rules) or user-defined rules (yes, I have all-identical disks now but this will let me add a read/write SSD cache in the future). If it's user-defined rules, these rules should have the ability to promote to SSD on a file level and not a block level. Space-efficient packing of small files I tried ZFS on Linux but the limitations were: Upgrading is additional work because the package is in an external repository and is tied to specific kernel versions; it is not integrated with the package manager Write IOPS does not scale with number of devices in a raidz vdev. Cannot add disks to raidz vdevs Cannot have select data on RAID0 to reduce overhead and improve performance without additional physical disks or giving ZFS a single partition of the disks ext4 on LVM2 looks like an option except I can't tell whether I can shrink, extend, and redistribute onto new spindles RAID-type logical volumes (of course, I can experiment with LVM on a bunch of files). As far as I can tell, it doesn't have any of the nice-to-haves so I was wondering if there is something better out there. I did look at LVM dangers and caveats but then again, no system is perfect.

  Read the article

• DDWRT VLAN Without internet

  - by user148888

  Hey i have WRT54G with DD-WRT v24-sp2 firmware. i got this scenario Vlan0 port 2,3,4 172.168.1.1/24 vlan1 Wan port Vlan2 port 1 172.168.2.1/24 i can ping from vlan0 to vlan2 but vlan2 can't ping to vlan0 iptables -I FORWARD -i vlan2 -o vlan1 -j DROP i use this to prevent vlan2 to have internet cuz i don't want to share my internet to vlan2 i just want to share local network betwen vlan1 and vlan2.. any help please :S:S:S

  Read the article

• nginx+passenger +static websites= problems

  - by Eugene K

  I've got a Rails app that nginx serves through passenger. I'd also like to serve some static content for a different domain name. But when I add another server block to my config, both websites become unavailable returning HTTP 204. What have I done wrong? What can I do to fix it? Here's the http block of my nginx.conf: https://gist.github.com/4243256 Here's what I added : server { listen 80; server_name website2; root /var/www/website2; location / { index index.html; } } It's going to be a Rails app as well at some point in the future (though I'm not really sure about that, maybe I'm going to use a different back-end solution.) Either way, I don't want anything dynamic to eat away the resources just yet. As of now, this website consists of nothing but index.html and stylesheet.css files in the root directory. What should I do? Thank you in advance. Sincerely yours, Eugene.

  Read the article

• Rate limit a wireless interface

  - by Jamie Hankins

  I have access to my routers SSH and IPTables. I want to rate limit my guest network to 1Mb/s so they can't guzzle my bandwidth. rai1 RTWIFI SoftAP ESSID:"GuestNetwork" Nickname:"" Mode:Managed Channel=6 Access Point: :F9 Bit Rate=300 Mb/s wdsi0 RTWIFI SoftAP ESSID:"YouCan'tTouchThis" Nickname:"" Mode:Managed Channel=6 Access Point: :F8 Bit Rate=300 Mb/s wdsi1 RTWIFI SoftAP ESSID:"YouCan'tTouchThis" Nickname:"" Mode:Managed Channel=6 Access Point: :F9 Bit Rate=300 Mb/s wdsi2 RTWIFI SoftAP ESSID:"YouCan'tTouchThis" Nickname:"" Mode:Managed Channel=6 Access Point: Not-Associated Bit Rate:300 Mb/s wdsi3 RTWIFI SoftAP ESSID:"YouCan'tTouchThis" Nickname:"" Mode:Managed Channel=6 Access Point: Not-Associated Bit Rate:300 Mb/s I'm just wondering the command I need to limit it. I tried the iwconfig limit command but it failed. Thanks

  Read the article

• How do I change the number of days a copied transaction log is kept in a log shipping configuration?

  - by Decker

  I think this is a pretty simple and perhaps stupid question. I've established log shipping between two SQL Server 2008 servers using the GUI (i.e. the SQL Server Management Studio). It's been running fine -- but now I want to change the number of days the copied files are retained on the secondary server. Is it simply a matter of going back to the GUI and change it there. Is it smart enough just to make that simple change or is the GUI only used to create the initial log shipping configuration?

  Read the article

• Strict security and virtual host isolation with Nginx?

  - by Hach-Que

  I currently have an Apache web server set up under which each virtual host is isolated using HTTPD-ITK and the AppArmor module. Each virtual host's workers are setuid/setgid by the server and are then placed in an AppArmor profile. I'm looking to use Nginx but I can't find any documentation on setting it up so that rather than the worker processes being shared between all virtual hosts, worker processes are per virtual host (and thus can be setuid / setgid). Is there any way to do this under Nginx?

  Read the article

• VMWare Newbie - looking for hardware recommendations and help :) [closed]

  - by Dan

  I am looking for some hardware recommendations on an upcoming virtualization project. We are a small company (80 users - 25 in site 1, 55 in site 2) currently using Windows Server 2003 - no VM servers yet. Our AD is setup where site 1 is the root domain and site 2 is a subdomain/subnet - connected by T1 and VPN for failover. The current DC's also server as file servers, print servers, AntiVirus servers. Email is in the cloud. Additionally then in site 1 we have 3 additional member servers - one running IBM Websphere for a customer specific app, one running Infor PowerLink (no real heavy load) and another that we use for Virtual Studio apps and also runs DirSync for Exchange Online. No heavy workloads on any of these machines really. We also have an AS400 box that we run ERP/CRM software on that site 2 connects to over the WAN link. In site 2 we also have a SQL machine that runs on Win2K server. Database files are not large less than 5 GB. Light to Medium workload on this machine. File servers in each site store less than 500 GB data and probably won't grow to more than 1TB in the next 5 years. I am looking to go to VMWare in both sites and virtualize all servers. What recommendations do you have for server, storage hardware? Is it safe to virtualize all of your DC's? Any help or advice would be greatly appreciated. Thanks.

  Read the article

• Cannot ping my domain-joined server - Can only ping domain controller - host unreachable

  - by Vazgen

  I have a HyperV Server hosting a Domain Controller VM (192.168.1.50) and another VM (192.168.1.51) joined to this domain. I have: domain controller as DNS server forward lookup zone for the domain with host record for 192.168.1.50 and 192.168.1.51 Windows client has primary DNS server set to 192.168.1.50 and secondary to my ISP I can ping 192.168.1.50 (domain controller) successfully but cannot ping 192.168.1.51 (domain-joined VM) When pinging from Windows client: ping 192.168.1.51 Reply from 192.168.1.129 : Destination host unreachable When pinging from Domain Controller: ping 192.168.1.51 Reply from 192.168.1.50 : Destination host unreachable I have 2 virtual network adapters one PRIVATE for intranet (set to static IP 192.168.1.51) and one PUBLIC for internet with a dynamic IP. I noticed the the PUBLIC one inherited the "mydomain.com" domain subtitle after joining the domain... I don't know what this meant but it seemed more intuitive to me to switch THIS ONE to have the static IP. After I configured that I still could not ping but now I get: ping 192.168.1.51 Request timed out What seems to be the issue, I'm relatively new to networking.

  Read the article

• How can I build pyv8 from source on FreeBSD against the v8 port?

  - by Utkonos

  I am unable to build pyv8 from source on FreeBSD. I have installed the /usr/ports/lang/v8 port, and I'm running into the following error. It seems that pyv8 wants to build v8 itself even though v8 is already built and installed. How can I point pyv8 to the already installed location of v8? # python setup.py build Found Google v8 base on V8_HOME , update it to the latest SVN trunk at running build ==================== INFO: Installing or updating GYP... -------------------- INFO: Check out GYP from SVN ... DEBUG: make dependencies ERROR: Check out GYP from SVN failed: code=2 DEBUG: "Makefile", line 43: Missing dependency operator "Makefile", line 45: Need an operator "Makefile", line 46: Need an operator "Makefile", line 48: Need an operator "Makefile", line 50: Need an operator "Makefile", line 52: Need an operator "Makefile", line 54: Missing dependency operator "Makefile", line 56: Need an operator "Makefile", line 58: Missing dependency operator "Makefile", line 60: Need an operator "Makefile", line 62: Missing dependency operator "Makefile", line 64: Need an operator "Makefile", line 66: Missing dependency operator "Makefile", line 68: Need an operator "Makefile", line 70: Missing dependency operator "Makefile", line 72: Need an operator "Makefile", line 73: Missing dependency operator "Makefile", line 75: Need an operator "Makefile", line 77: Missing dependency operator "Makefile", line 79: Need an operator "Makefile", line 81: Missing dependency operator "Makefile", line 83: Need an operator "Makefile", line 85: Missing dependency operator "Makefile", line 87: Need an operator "Makefile", line 89: Need an operator "Makefile", line 91: Missing dependency operator "Makefile", line 93: Need an operator "Makefile", line 95: Need an operator "Makefile", line 97: Need an operator "Makefile", line 99: Missing dependency operator "Makefile", line 101: Need an operator "Makefile", line 103: Missing dependency operator "Makefile", line 105: Need an operator "Makefile", line 107: Missing dependency operator "Makefile", line 109: Need an operator "Makefile", line 111: Missing dependency operator "Makefile", line 113: Need an operator "Makefile", line 115: Missing dependency operator "Makefile", line 117: Need an operator Error expanding embedded variable. ==================== INFO: Patching the GYP scripts INFO: patch the Google v8 build/standalone.gypi file to enable RTTI and C++ Exceptions ==================== INFO: building Google v8 with GYP for x64 platform with release mode -------------------- INFO: build v8 from SVN ... DEBUG: make verifyheap=off component=shared_library visibility=on gdbjit=off liveobjectlist=off regexp=native disassembler=off objectprint=off debuggersupport=on extrachecks=off snapshot=on werror=on x64.release ERROR: build v8 from SVN failed: code=2 DEBUG: "Makefile", line 43: Missing dependency operator "Makefile", line 45: Need an operator "Makefile", line 46: Need an operator "Makefile", line 48: Need an operator "Makefile", line 50: Need an operator "Makefile", line 52: Need an operator "Makefile", line 54: Missing dependency operator "Makefile", line 56: Need an operator "Makefile", line 58: Missing dependency operator "Makefile", line 60: Need an operator "Makefile", line 62: Missing dependency operator "Makefile", line 64: Need an operator "Makefile", line 66: Missing dependency operator "Makefile", line 68: Need an operator "Makefile", line 70: Missing dependency operator "Makefile", line 72: Need an operator "Makefile", line 73: Missing dependency operator "Makefile", line 75: Need an operator "Makefile", line 77: Missing dependency operator "Makefile", line 79: Need an operator "Makefile", line 81: Missing dependency operator "Makefile", line 83: Need an operator "Makefile", line 85: Missing dependency operator "Makefile", line 87: Need an operator "Makefile", line 89: Need an operator "Makefile", line 91: Missing dependency operator "Makefile", line 93: Need an operator "Makefile", line 95: Need an operator "Makefile", line 97: Need an operator "Makefile", line 99: Missing dependency operator "Makefile", line 101: Need an operator "Makefile", line 103: Missing dependency operator "Makefile", line 105: Need an operator "Makefile", line 107: Missing dependency operator "Makefile", line 109: Need an operator "Makefile", line 111: Missing dependency operator "Makefile", line 113: Need an operator "Makefile", line 115: Missing dependency operator "Makefile", line 117: Need an operator Error expanding embedded variable. The files that are installed by the v8 port are the following (in /usr/local): bin/d8 include/v8.h include/v8-debug.h include/v8-preparser.h include/v8-profiler.h include/v8-testing.h include/v8stdint.h lib/libv8.so lib/libv8.so.1

  Read the article

< Previous Page | 109 110 111 112 113 114 115 116 117 118 119 120  | Next Page >