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  • How should I go about implementing a points-to analysis in Maude?

    - by reprogrammer
    I'm going to implement a points-to analysis algorithm. I'd like to implement this analysis mainly based on the algorithm by Whaley and Lam. Whaley and Lam use a BDD based implementation of Datalog to represent and compute the points-to analysis relations. The following lists some of the relations that are used in a typical points-to analysis. Note that D(w, z) :- A(w, x),B(x, y), C(y, z) means D(w, z) is true if A(w, x), B(x, y), and C(y, z) are all true. BDD is the data structure used to represent these relations. Relations input vP0 (variable : V, heap : H) input store (base : V, field : F, source : V) input load (base : V, field : F, dest : V) input assign (dest : V, source : V) output vP (variable : V, heap : H) output hP (base : H, field : F, target : H) Rules vP(v, h) :- vP0(v, h) vP(v1, h) :- assign(v1, v2), vP(v2, h) hP(h1, f,h2) :- store(v1, f, v2), vP(v1, h1), vP(v2, h2) vP(v2, h2) :- load(v1, f, v2), vP(v1, h1), hP(h1, f, h2) I need to understand if Maude is a good environment for implementing points-to analysis. I noticed that Maude uses a BDD library called BuDDy. But, it looks like that Maude uses BDDs for a different purpose, i.e. unification. So, I thought I might be able to use Maude instead of a Datalog engine to compute the relations of my points-to analysis. I assume Maude propagates independent information concurrently. And this concurrency could potentially make my points-to analysis faster than sequential processing of rules. But, I don't know the best way to represent my relations in Maude. Should I implement BDD in Maude myself, or Maude's internal unification based on BDD has the same effect?

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  • A/UX cc compiler errors on trivial code: "declared argument argc is missing"

    - by Fzn
    On a quite ancient UNIX (Apple A/UX 3.0.1 for 680x0 processors) using the built-in c compiler (cc), this issue arrises. Here is the code I'm trying to compile: #include <stdlib.h> #include <stdio.h> int main() int argc; char **argv; { if (argc > 1) puts(argv[1]); return (EXIT_SUCCESS); } And here is the output I get: pigeonz.root # cc -c test.c "test.c", line 5: declared argument argc is missing "test.c", line 6: declared argument argv is missing Using a more modern prototype did not help, nor did the manual page, nor a quick google search. What am I doing wrong?

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  • Compiling Visual c++ programs from the command line and msvcr90.dll

    - by Stanley kelly
    Hi, When I compile my Visual c++ 2008 express program from inside the IDE and redistribute it on another computer, It starts up fine without any dll dependencies that I haven't accounted for. When I compile the same program from the visual c++ 2008 command line under the start menu and redistribute it to the other computer, it looks for msvcr90.dll at start-up. Here is how it is compiled from the command line cl /Fomain.obj /c main.cpp /nologo -O2 -DNDEBUG /MD /ID:(list of include directories) link /nologo /SUBSYSTEM:WINDOWS /ENTRY:mainCRTStartup /OUT:Build\myprogram.ex e /LIBPATH:D:\libs (list of libraries) and here is how the IDE builds it based on the relevant parts of the build log. /O2 /Oi /GL /I clude" /I (list of includes) /D "WIN32" /D "NDEBUG" /D "_CONSOLE" /D "_UNICODE" /D "UNICODE" /FD /EHsc /MD /Gy /Yu"stdafx.h" /Fp"Release\myprogram" /Fo"Release\\" /Fd"Release\vc90.pdb" /W3 /c /Zi /TP /wd4250 /vd2 Creating command line "cl.exe @d:\myprogram\Release\RSP00000118003188.rsp /nologo /errorReport:prompt" /OUT:"D:\myprgram\Release\myprgram.exe" /INCREMENTAL:NO /LIBPATH:"d:\gtkmm\lib" /MANIFEST /MANIFESTFILE:"Release\myprogam.exe.intermediate.manifest" /MANIFESTUAC:"level='asInvoker' uiAccess='false'" /DEBUG /PDB:"d:\myprogram\Release\myprogram.pdb" /SUBSYSTEM:WINDOWS /OPT:REF /OPT:ICF /LTCG /ENTRY:"mainCRTStartup" /DYNAMICBASE /NXCOMPAT /MACHINE:X86 (list of libraries) Creating command line "link.exe @d:\myprogram\Release\RSP00000218003188.rsp /NOLOGO /ERRORREPORT:PROMPT" /outputresource:"..\Release\myprogram.exe;#1" /manifest .\Release\myprogram.exe.intermediate.manifest Creating command line "mt.exe @d:\myprogram\Release\RSP00000318003188.rsp /nologo" I would like to be able to compile it from the command line and not have it look for such a late version of the runtime dll, like the version compiled from the IDE seems not to do. Both versions pass /MD to the compiler, so i am not sure what to do.

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  • Boost Thread Specific Storage Question (boost/thread/tss.hpp)

    - by Hassan Syed
    The boost threading library has an abstraction for thread specific (local) storage. I have skimmed over the source code and it seems that the TSS functionality can be used in an application with any existing thread regardless of weather it was created from boost::thread --i.e., this implies that certain callbacks are registered with the kernel to hook in a callback function that may call the destructor of any TSS objects when the thread or process is going out of scope. I have found these callbacks. I need to cache HMAC_CTX's from OpenSSL inside the worker threads of various web-servers (see this, detailed, question for what I am trying to do), and as such I do not controll the life-time of the thread -- the web-server does. Therefore I will use the TSS functionality on threads not created by boost::thread. I just wanted to validate my assumptions before I started implementing the caching logic, are there any flaws in my logic ?

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  • sendto: Invalid Argument

    - by Sylvain
    Hi, I have a list<struct sockaddr_in> _peers I'd like to use for sendto() the list is filled this way struct hostent *hp; hp = gethostbyname(hostname); sockaddr_in sin; bzero(&sin, sizeof(sin)); sin.sin_family = AF_INET; sin.sin_port = htons(port); sin.sin_addr.s_addr = *(in_addr_t *)hp->h_addr; _peers.push_front(sin); and here's how I try to send: for (list<struct sockaddr_in>::iterator it = _peers.begin(); it != _peers.end(); ++it) { if (sendto(_s, "PING", 5, 0, (struct sockaddr *)&(*it), sizeof(struct sockaddr_in)) < 0) perror("sendto"); } outputs: sendto: Invalid argument If I create the struct sockaddr_in right before sendto(), everything works fine, so I guess I fail at using the list properly ... I also tested using &_peers.front() directly and still get the same error ... what am I doing wrong? Thanks in advance,

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  • Create a VPN with Python

    - by user213060
    I want to make a device "tunnel box" that you plug an input ethernet line, and an output ethernet line, and all the traffic that goes through it gets modified in a special way. This is similar to how a firewall, IDS, VPN, or similar boxes are connected inline in a network. I think you can just assume that I am writing a custom VPN in Python for the purpose of this question: LAN computer <--\ LAN computer <---> [LAN switch] <--> ["tunnel box"] <--> [internet modem] <--> LAN computer <--/ My question is, what is a good way to program this "tunnel box" from python? My application needs to see TCP flows at the network layer, not as individual ethernet frames. Non-TCP/IP traffic such as ICPM and other types should just be passed through. Example Twisted-like Code for my "tunnel box" tunnel appliance: from my_code import special_data_conversion_function class StreamInterceptor(twisted.Protocol): def dataReceived(self,data): data=special_data_conversion_function(data) self.outbound_connection.send(data) My initial guesses: TUN/TAP with twisted.pair.tuntap.py - Problem: This seems to only work at the ethernet frame level, not like my example? Socks proxy - Problem: Not transparent as in my diagram. Programs have to be specifically setup for it. Thanks!

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  • Is the IP from the source or target in this System.Net.Sockets.SocketException?

    - by Jeremy Mullin
    I'm making an outbound connection using a DNS name to a server other than the localhost, and I get this exception: System.Net.WebException: Unable to connect to the remote server --- System.Net.Sockets.SocketException: No connection could be made because the target machine actively refused it 127.0.0.1:5555 The text implies that the TARGET machine refused the connection, but the IP address and port are from the localhost, which is kind of confusing. So is that IP address really the outgoing IP and port, even though the exception was caused by the target refusing the connection? Or is the exception from the local firewall blocking the outgoing connection?

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  • Novel fitness measure for evolutionary image matching simulation

    - by Nick Johnson
    I'm sure many people have already seen demos of using genetic algorithms to generate an image that matches a sample image. You start off with noise, and gradually it comes to resemble the target image more and more closely, until you have a more-or-less exact duplicate. All of the examples I've seen, however, use a fairly straightforward pixel-by-pixel comparison, resulting in a fairly predictable 'fade in' of the final image. What I'm looking for is something more novel: A fitness measure that comes closer to what we see as 'similar' than the naive approach. I don't have a specific result in mind - I'm just looking for something more 'interesting' than the default. Suggestions?

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  • Javascript comma operator

    - by Claudiu
    When combining assignment with comma (something that you shouldn't do, probably), how does javascript determine which value is assigned? Consider these two snippets: function nl(x) { document.write(x + "<br>"); } var i = 0; nl(i+=1, i+=1, i+=1, i+=1); nl(i); And: function nl(x) { document.write(x + "<br>"); } var i = 0; nl((i+=1, i+=1, i+=1, i+=1)); nl(i); The first outputs 1 4 while the second outputs 4 4 What are the parentheses doing here?

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  • Evolutionary Algorithms: Optimal Repopulation Breakdowns

    - by Brian MacKay
    It's really all in the title, but here's a breakdown for anyone who is interested in Evolutionary Algorithms: In an EA, the basic premise is that you randomly generate a certain number of organisms (which are really just sets of parameters), run them against a problem, and then let the top performers survive. You then repopulate with a combination of crossbreeds of the survivors, mutations of the survivors, and also a certain number of new random organisms. Do that several thousand times, and efficient organisms arise. Some people also do things like introduce multiple "islands" of organisms, which are seperate populations that are allowed to crossbreed once in awhile. So, my question is: what are the optimal repopulation percentages? I have been keeping the top 10% performers, and repopulating with 30% crossbreeds and 30% mutations. The remaining 30% is for new organisms. I have also tried out the multiple island theory, and I'm interested in your results on that as well. It is not lost on me that this is exactly the type of problem an EA could solve. Are you aware of anyone trying that? Thanks in advance!

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  • Scalaz: request for use case for Cokleisli composition

    - by oxbow_lakes
    This question isn't meant as flame-bait! As it might be apparent, I've been looking at Scalaz recently. I'm trying to understand why I need some of the functionality that the library provides. Here's something: import scalaz._ import Scalaz._ type NEL[A] = NonEmptyList[A] val NEL = NonEmptyList I put some println statements in my functions to see what was going on (aside: what would I have done if I was trying to avoid side effects like that?). My functions are: val f: NEL[Int] => String = (l: NEL[Int]) => {println("f: " + l); l.toString |+| "X" } val g: NEL[String] => BigInt = (l: NEL[String]) => {println("g: " + l); BigInt(l.map(_.length).sum) } Then I combine them via a cokleisli and pass in a NEL[Int] val k = cokleisli(f) =>= cokleisli(g) println("RES: " + k( NEL(1, 2, 3) )) What does this print? f: NonEmptyList(1, 2, 3) f: NonEmptyList(2, 3) f: NonEmptyList(3) g: NonEmptyList(NonEmptyList(1, 2, 3)X, NonEmptyList(2, 3)X, NonEmptyList(3)X) RES: 57 The RES value is the character count of the (String) elements in the final NEL. Two things occur to me: How could I have known that my NEL was going to be reduced in this manner from the method signatures involved? (I wasn't expecting the result at all) What is the point of this? Can a reasonably simple and easy-to-follow use case be distilled for me? This question is a thinly-veiled plea for some lovely person like retronym to explain how this powerful library actually works.

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  • Setting article properties for a publication using RMO in C# .NET

    - by Pavan Kumar
    I am using transaction replication with push subscription. I am developing a UI for replication using RMO in C#.NET between different instances of the same database within same machine holding similar schema and structure. I am using Single subscriber and multiple publisher topology. During creation of publication i want to set a few article properties such as Keep the existing object unchanged ,allow schema changes at subscriber to false a,copy foriegn key constarint and copy check constraints to true. How do i set the article properties using RMO in C# .NET. I am using Visual Studio 2008 SP1.I also want to know as how we can select all the objects including Tables,Views,Stored Procedures for publishing at one stretch. I could do it for one table but i want to select all the tables at one stretch. This is the code snippet i used for selecting single table for publishing. TransArticle ta = new TransArticle(); ta.Name = "Article_1"; ta.PublicationName = "TransReplication_DB2"; ta.DatabaseName = "DB2"; ta.SourceObjectName = "person"; ta.SourceObjectOwner = "dbo"; ta.ConnectionContext = conn; ta.Create();

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  • Recommended Math textbooks for programmers

    - by Tony
    I learned math in a non-English environment, I recently read some books about algorithm analysis, I found some math concepts were confusing, and seemed not the same as what I've learned. What math textbooks would you recommend that covers math concepts from the scratch and suitable for self-learning ?

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  • C# StreamReader.EndOfStream produces IOException

    - by Ziplin
    I'm working on an application that accepts TCP connections and reads in data until an </File> marker is read and then writes that data to the filesystem. I don't want to disconnect, I want to let the client sending the data to do that so they can send multiple files in one connection. I'm using the StreamReader.EndOfStream around my outter loop, but it throws an IOException when the client disconnects. Is there a better way to do this? private static void RecieveAsyncStream(IAsyncResult ar) { TcpListener listener = (TcpListener)ar.AsyncState; TcpClient client = listener.EndAcceptTcpClient(ar); // init the streams NetworkStream netStream = client.GetStream(); StreamReader streamReader = new StreamReader(netStream); StreamWriter streamWriter = new StreamWriter(netStream); while (!streamReader.EndOfStream) // throws IOException { string file= ""; while (file!= "</File>" && !streamReader.EndOfStream) { file += streamReader.ReadLine(); } // write file to filesystem } listener.BeginAcceptTcpClient(RecieveAsyncStream, listener); }

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  • How do I make a module in PLT Scheme?

    - by kunjaan
    I tried doing this: #lang scheme (module duck scheme/base (provide num-eggs quack) (define num-eggs 2) (define (quack n) (unless (zero? n) (printf "quack\n") (quack (sub1 n))))) But I get this error: module: illegal use (not at top-level) in: (module duck scheme/base (provide num-eggs quack) (define num-eggs 2) (define (quack n) (unless (zero? n) (printf "quack\n") (quack (sub1 n))))) what is the correct way?

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  • Why doesn't Python require exactly four spaces per indentation level?

    - by knorv
    Whitespace is signification in Python in that code blocks are defined by their indentation. Furthermore, Guido van Rossum recommends using four spaces per indentation level (see PEP 8: Style Guide for Python Code). What was the reasoning behind not requiring exactly four spaces per indentation level as well? Are there any technical reasons? It seems like all the arguments that can be made for making whitespace define code blocks can also be used to argument for setting an exact whitespace length for one indentation level (say four spaces).

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  • Linux Kernel - traverse to buffer heads

    - by CodeRanger
    In the Linux kernel, is there a way to traverse down to the buffer_heads from within a module? I can see how to get to struct bio (task_struct macro: current-bio). But how can I get to the buffer heads? The buffer_head struct holds some information I'd like to obtain at any point regarding physical block numbers.

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  • Microsoft Quotation

    - by Asad Jibran Ahmed
    I don't know if this is the right place to ask this question, but I honestly have exhausted my self searching for the last hour. I am looking for a quotation made about Microsofts software. It goes something along the lines of: "They may make 2nd grade crappy software, but by God they know how to design interfaces" It was by a somewhat popular open source personality about the lack of good interface design in open source software. Does any one know the exact quotation? It will be a great help if someone can point me in the right direction.

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  • Array: mathematical sequence

    - by VaioIsBorn
    An array of integers A[i] (i 1) is defined in the following way: an element A[k] ( k 1) is the smallest number greater than A[k-1] such that the sum of its digits is equal to the sum of the digits of the number 4* A[k-1] . You need to write a program that calculates the N th number in this array based on the given first element A[1] . INPUT: In one line of standard input there are two numbers seperated with a single space: A[1] (1 <= A[1] <= 100) and N (1 <= N <= 10000). OUTPUT: The standard output should only contain a single integer A[N] , the Nth number of the defined sequence. Input: 7 4 Output: 79 Explanation: Elements of the array are as follows: 7, 19, 49, 79... and the 4th element is solution. I tried solving this by coding a separate function that for a given number A[k] calculates the sum of it's digits and finds the smallest number greater than A[k-1] as it says in the problem, but with no success. The first testing failed because of a memory limit, the second testing failed because of a time limit, and now i don't have any possible idea how to solve this. One friend suggested recursion, but i don't know how to set that. Anyone who can help me in any way please write, also suggest some ideas about using recursion/DP for solving this problem. Thanks.

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  • Apache HttpClient CoreConnectionPNames.CONNECTION_TIMEOUT does nothing ?

    - by Maxim Veksler
    Hi, I'm testing some result from HttpClient that looks irrational. It seems that setting CoreConnectionPNames.CONNECTION_TIMEOUT = 1 has no effect because send request to different host return successfully with connect timeout 1 which IMHO can't be the case (1ms to setup TCP handshake???) Am I misunderstood something or is something very strange going on here? The httpclient version I'm using as can be seen in this pom.xml is <dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpclient</artifactId> <version>4.0.1</version> <type>jar</type> </dependency> Here is the code: import java.io.IOException; import java.util.Random; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.client.ClientProtocolException; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpGet; import org.apache.http.client.methods.HttpUriRequest; import org.apache.http.impl.client.DefaultHttpClient; import org.apache.http.params.CoreConnectionPNames; import org.apache.http.util.EntityUtils; import org.apache.log4j.Logger; public class TestNodeAliveness { private static Logger log = Logger.getLogger(TestNodeAliveness.class); public static boolean nodeBIT(String elasticIP) throws ClientProtocolException, IOException { try { HttpClient client = new DefaultHttpClient(); // The time it takes to open TCP connection. client.getParams().setParameter(CoreConnectionPNames.CONNECTION_TIMEOUT, 1); // Timeout when server does not send data. client.getParams().setParameter(CoreConnectionPNames.SO_TIMEOUT, 5000); // Some tuning that is not required for bit tests. client.getParams().setParameter(CoreConnectionPNames.STALE_CONNECTION_CHECK, false); client.getParams().setParameter(CoreConnectionPNames.TCP_NODELAY, true); HttpUriRequest request = new HttpGet("http://" + elasticIP); HttpResponse response = client.execute(request); HttpEntity entity = response.getEntity(); if(entity == null) { return false; } else { System.out.println(EntityUtils.toString(entity)); } // Close just in case. request.abort(); } catch (Throwable e) { log.warn("BIT Test failed for " + elasticIP); e.printStackTrace(); return false; } return true; } public static void main(String[] args) throws ClientProtocolException, IOException { nodeBIT("google.com?cant_cache_this=" + (new Random()).nextInt()); } } Thank you.

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  • FireLog: proper installation...

    - by kent
    I have installed the firewiresdk26 on my dev mac... and in the Tools/ directory is FireLog. I have run the FireLog 2.0.0.pkg installer on my dev mac, but the payload it deploys is installed in my /System/Library tree, as opposed to my /Developer/SDKs tree. so when I try to include the header iokit/firewire/FireLog.h it does not get found. am I missing something? or doing something wrong? or is this an error in the installer (either FW26 or FireLog installers?) I realize that the FireLog installer is intended to be run on the machine to be debugged remotely and thus it makes sense that the framework is placed in the /System/Library path, however none of the installers gets it into my developer path... I guess I just have to move it over there by hand, but before I do that I wanted to see if I'm just overlooking something silly and need to read the docs with more concentration or something... anyone run into this before? [thx]

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