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  • running examples in package-Ex.R failed

    - by swarna
    Hi,My name is Swarna,I'm new to R,when i was checking my package i got a error message saying "Running examples in package-Ex.R failed" and series of statement saying where error might have occurred name of the package -package flush(stderr());flush(stdout()) name: title alias keywords Can any one please help me with this. Thank you,

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  • What language/compiler for native running of application in any windows(XP/Vista/7) platform?

    - by Xinxua
    Hi, I want to develop an application that runs on any windows platform (XP, Vista, 7) but does not require a dependency like .NET Framework or JVM. I have given the other requirements below: Runs in any windows platform Must have GUI libraries to create windows/primitive controls I also want the output file size of the application to be minimal (So cannot include .net frameword etc in the exe file) Any suggestions for this requirement?

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  • Passing a hostname of over 255 characters to getaddrinfo causes a getaddrinfo failed: memory allocat

    - by darrickc
    I am currently upgrading our software to support ipv6 and in the meantime I'm expanding hostname/ip fields to the max hostname size. In sun documentation it seems like this can be up to 1025 (netdb.h:#define NI_MAXHOST 1025 - this is the recommended hostname allocation define), but when I pass a hostname of over 255 to getaddrinfo I get "getaddrinfo failed: memory allocation failure". I am testing on a Sol10 box. Ideas?

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  • Most efficient way for testing links

    - by Burnzy
    I'm currently developping an app that is going through all the files on a server and checking every single hrefs to check wether they are valid or not. Using a WebClient or a HttpWebRequest/HttpWebResponse is kinda overkilling the process because it downloads the whole page each time, which is useless, I only need to check if the link do not return 404. What would be the most efficient way? Socket seems to be a good way of doing it, however I'm not quite sure how this works. Thanks for sharing your expertise!

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  • From a programmer's perspective, which is your everyday Python uses?

    - by Vimvq1987
    I've finished my thesis and now having a free time. I intend to learn another language, and Python seems to be a good choice. I'll probably have to use .NET for every day works, but I heard that Python helps programmer a lot, in mean of automation. That would be great if I can write "small" Python scripts to do something automatically. From a programmer's perspective, which is your everyday Python's uses? What did it do to have your works done?

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  • Replace ",**" with a linebreak using RegEx (or something else)

    - by John
    I'm getting started with RegEx and I was wondering if anyone could help me craft a statement to convert coordinates as follows: 145.00694,-37.80421,9 145.00686,-37.80382,9 145.00595,-37.8035,16 145.00586,-37.80301,16 to 145.00694,-37.80421 145.00686,-37.80382 145.00595,-37.8035 145.00586,-37.80301 (Strip off the last comma and value and turn it into a line break.) I can't figure out how to use wildcards to do something like that. Any help would be greatly appreciated! Thanks.

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  • simple question on C

    - by lego69
    I have this snippet of the code char *str = “123”; if(str[0] == 1) printf("Hello\n"); why I can't receive my Hello thanks in advance! how exactly compiler does this comparison if(str[0] == 1)?

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  • Serializing persistent/functional data structures

    - by Rob
    Persistent data structures depend on the sharing of structure for efficiency. For an example, see here. How can I preserve the structure sharing when I serialize the data structures and write them to a file or database? If I just naively traverse the datastructures, I'll store the correct values, but I'll lose the structure sharing. I'd like to be able to save data-structures with shared components to a file, restore them, and still have most of the structure shared in the restored data.

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  • Need some testcases on solving this problem

    - by user285825
    I am trying to solve the minesweeper problem of acm problemset archive, http://uva,onlinejudge,org/index,php?option=com_onlinejudge&Itemid=8&category=13&page=show_problem&problem=1130 I tested with all the possible cases that I can imagine of: 1, minimum 1 1 , 1 1 # 2, maximum upto 100 upto 100 repeat until 100 3, for each position I test for mine 4 4 ,,, ,,,, ,,,, 4 4 ,#,, ,,,, ,,,, ,,,, lastly 4 4 ,,,, ,,,, ,,,, ,,,# 4, for each postion I put a ',' and surround it with mines 4 4 ,### # # # 4 4 , # # # lastly 4 4 # # # , I thought that these are reasonable and representative sets of testcases, But still Wrong answer, I am not sure what else could I test for, I would be glad if someone throw some light on further strategy to test this thing,

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  • functional, bind1st and mem_fun

    - by Neil G
    Why won't this compile? #include <functional> #include <boost/function.hpp> class A { A() { typedef boost::function<void ()> FunctionCall; FunctionCall f = std::bind1st(std::mem_fun(&A::process), this); } void process() {} }; Errors: In file included from /opt/local/include/gcc44/c++/bits/stl_function.h:712, from /opt/local/include/gcc44/c++/functional:50, from a.cc:1: /opt/local/include/gcc44/c++/backward/binders.h: In instantiation of 'std::binder1st<std::mem_fun_t<void, A> >': a.cc:7: instantiated from here /opt/local/include/gcc44/c++/backward/binders.h:100: error: no type named 'second_argument_type' in 'class std::mem_fun_t<void, A>' /opt/local/include/gcc44/c++/backward/binders.h:103: error: no type named 'first_argument_type' in 'class std::mem_fun_t<void, A>' /opt/local/include/gcc44/c++/backward/binders.h:106: error: no type named 'first_argument_type' in 'class std::mem_fun_t<void, A>' /opt/local/include/gcc44/c++/backward/binders.h:111: error: no type named 'second_argument_type' in 'class std::mem_fun_t<void, A>' /opt/local/include/gcc44/c++/backward/binders.h:117: error: no type named 'second_argument_type' in 'class std::mem_fun_t<void, A>' /opt/local/include/gcc44/c++/backward/binders.h: In function 'std::binder1st<_Operation> std::bind1st(const _Operation&, const _Tp&) [with _Operation = std::mem_fun_t<void, A>, _Tp = A*]': a.cc:7: instantiated from here /opt/local/include/gcc44/c++/backward/binders.h:126: error: no type named 'first_argument_type' in 'class std::mem_fun_t<void, A>' In file included from /opt/local/include/boost/function/detail/maybe_include.hpp:13, from /opt/local/include/boost/function/detail/function_iterate.hpp:14, from /opt/local/include/boost/preprocessor/iteration/detail/iter/forward1.hpp:47, from /opt/local/include/boost/function.hpp:64, from a.cc:2: /opt/local/include/boost/function/function_template.hpp: In static member function 'static void boost::detail::function::void_function_obj_invoker0<FunctionObj, R>::invoke(boost::detail::function::function_buffer&) [with FunctionObj = std::binder1st<std::mem_fun_t<void, A> >, R = void]': /opt/local/include/boost/function/function_template.hpp:913: instantiated from 'void boost::function0<R>::assign_to(Functor) [with Functor = std::binder1st<std::mem_fun_t<void, A> >, R = void]' /opt/local/include/boost/function/function_template.hpp:722: instantiated from 'boost::function0<R>::function0(Functor, typename boost::enable_if_c<boost::type_traits::ice_not::value, int>::type) [with Functor = std::binder1st<std::mem_fun_t<void, A> >, R = void]' /opt/local/include/boost/function/function_template.hpp:1064: instantiated from 'boost::function<R()>::function(Functor, typename boost::enable_if_c<boost::type_traits::ice_not::value, int>::type) [with Functor = std::binder1st<std::mem_fun_t<void, A> >, R = void]' a.cc:7: instantiated from here /opt/local/include/boost/function/function_template.hpp:153: error: no match for call to '(std::binder1st<std::mem_fun_t<void, A> >) ()'

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  • What about parallelism across network using multiple PCs?

    - by MainMa
    Parallel computing is used more and more, and new framework features and shortcuts make it easier to use (for example Parallel extensions which are directly available in .NET 4). Now what about the parallelism across network? I mean, an abstraction of everything related to communications, creation of processes on remote machines, etc. Something like, in C#: NetworkParallel.ForEach(myEnumerable, () => { // Computing and/or access to web ressource or local network database here }); I understand that it is very different from the multi-core parallelism. The two most obvious differences would probably be: The fact that such parallel task will be limited to computing, without being able for example to use files stored locally (but why not a database?), or even to use local variables, because it would be rather two distinct applications than two threads of the same application, The very specific implementation, requiring not just a separate thread (which is quite easy), but spanning a process on different machines, then communicating with them over local network. Despite those differences, such parallelism is quite possible, even without speaking about distributed architecture. Do you think it will be implemented in a few years? Do you agree that it enables developers to easily develop extremely powerfull stuff with much less pain? Example: Think about a business application which extracts data from the database, transforms it, and displays statistics. Let's say this application takes ten seconds to load data, twenty seconds to transform data and ten seconds to build charts on a single machine in a company, using all the CPU, whereas ten other machines are used at 5% of CPU most of the time. In a such case, every action may be done in parallel, resulting in probably six to ten seconds for overall process instead of forty.

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  • Function Overloading

    - by Sanju
    Let us suppose i have these three methods defined: int F1(int, int); int F1(float, float); Float F1(int, int); and i am calling method F1 here: Console.writeline(F1(5,6).ToString())); Which method it will call and why?

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  • Daemonize() issues on Debian

    - by djTeller
    Hi, I'm currently writing a multi-process client and a multi-treaded server for some project i have. The server is a Daemon. In order to accomplish that, i'm using the following daemonize() code: static void daemonize(void) { pid_t pid, sid; /* already a daemon */ if ( getppid() == 1 ) return; /* Fork off the parent process */ pid = fork(); if (pid < 0) { exit(EXIT_FAILURE); } /* If we got a good PID, then we can exit the parent process. */ if (pid > 0) { exit(EXIT_SUCCESS); } /* At this point we are executing as the child process */ /* Change the file mode mask */ umask(0); /* Create a new SID for the child process */ sid = setsid(); if (sid < 0) { exit(EXIT_FAILURE); } /* Change the current working directory. This prevents the current directory from being locked; hence not being able to remove it. */ if ((chdir("/")) < 0) { exit(EXIT_FAILURE); } /* Redirect standard files to /dev/null */ freopen( "/dev/null", "r", stdin); freopen( "/dev/null", "w", stdout); freopen( "/dev/null", "w", stderr); } int main( int argc, char *argv[] ) { daemonize(); /* Now we are a daemon -- do the work for which we were paid */ return 0; } I have a strange side effect when testing the server on Debian (Ubuntu). The accept() function always fail to accept connections, the pid returned is -1 I have no idea what causing this, since in RedHat & CentOS it works well. When i remove the call to daemonize(), everything works well on Debian, when i add it back, same accept() error reproduce. I've been monitring the /proc//fd, everything looks good. Something in the daemonize() and the Debian release just doesn't seem to work. (Debian GNU/Linux 5.0, Linux 2.6.26-2-286 #1 SMP) Any idea what causing this? Thank you

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  • Which is the best pick?

    - by Daniel
    Hi, considering I have experience with Java SE: which language should I learn(and is best for that purpose) in order to build web applications some day with it? I have been contemplating PHP and Java EE. The latter does indeed seems as an obvious choice given my Java SE knowledge. But how does it fares in comparison with PHP and how good is it for the aforementioned purpose? If there is a better language for this purpose, feel free to recommend it. Thank you.

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  • which ad solution is best for iPhone apps

    - by nbojja
    Hi All, i have a iPhone free app downloaded by 3000 users. mostly every one uses my app atleast once in a day. So i am planning to keep ads on my app. Which ad solution is best. and i looked in some sites. No one is giving clear details about CPMs. my direct question is "How much will i get for 1000 impressions using different ad solutions?" thanks

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  • inode_operations , warning: initialization from incompatible pointer type

    - by djTeller
    Hi everyone, I'm trying to compile a simple Kernel program that read and write from a proc file. I'm trying to set permission to that file by overriding the permission fp in inode_operations struct (.permission) static int module_permission(struct inode *inode, int op, struct nameidata *foo) { . . . } static struct inode_operations Inode_Ops_4_Our_Proc_File = { .permission = module_permission, /* check for permissions */ }; Our_Proc_File->proc_iops = &Inode_Ops_4_Our_Proc_File; For some reason, when I compile this i get - warning: initialization from incompatible pointer type on the following line: .permission = module_permission, /* check for permissions */ Any idea how to solve this? Thanks!

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  • Binding on a port with netpipes/netcat

    - by mindas
    I am trying to write a simple bash script that is listening on a port and responding with a trivial HTTP response. My specific issue is that I am not sure if the port is available and in case of bind failure I fall back to next port until bind succeeds. So far to me the easiest way to achieve this was something like: for (( i=$PORT_BASE; i < $(($PORT_BASE+$PORT_RANGE)); i++ )) do if [ $DEBUG -eq 1 ] ; then echo trying to bind on $i fi /usr/bin/faucet $i --out --daemon echo test 2>/dev/null if [ $? -eq 0 ] ; then #success? port=$i if [ $DEBUG -eq 1 ] ; then echo "bound on port $port" fi break fi done Here I am using faucet from netpipes Ubuntu package. The problem with this is that if I simply print "test" to the output, curl complains about non-standard HTTP response (error code 18). That's fair enough as I don't print HTTP-compatible response. If I replace echo test with echo -ne "HTTP/1.0 200 OK\r\n\r\ntest", curl still complains: user@server:$ faucet 10020 --out --daemon echo -ne "HTTP/1.0 200 OK\r\n\r\ntest" ... user@client:$ curl ip.of.the.server:10020 curl: (56) Failure when receiving data from the peer I think the problem lies in how faucet is printing the response and handling the connection. For example if I do the server side in netcat, curl works fine: user@server:$ echo -ne "HTTP/1.0 200 OK\r\n\r\ntest\r\n" | nc -l 10020 ... user@client:$ curl ip.of.the.server:10020 test user@client:$ I would be more than happy to replace faucet with netcat in my main script, but the problem is that I want to spawn independent server process to be able to run client from the same base shell. faucet has a very handy --daemon parameter as it forks to background and I can use $? (exit status code) to check if bind succeeded. If I was to use netcat for a similar purpose, I would have to fork it using & and $? would not work. Does anybody know why faucet isn't responding correctly in this particular case and/or can suggest a solution to this problem. I am not married neither to faucet nor netcat but would like the solution to be implemented using bash or it's utilities (as opposed to write something in yet another scripting language, such as Perl or Python).

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  • Writing an auto-memoizer in Scheme. Help with macro and a wrapper.

    - by kunjaan
    I am facing a couple of problems while writing an auto-memoizer in Scheme. I have a working memoizer function, which creats a hash table and checks if the value is already computed. If it has been computed before then it returns the value else it calls the function. (define (memoizer fun) (let ((a-table (make-hash))) (?(n) (define false-if-fail (?() #f)) (let ((return-val (hash-ref a-table n false-if-fail))) (if return-val return-val (begin (hash-set! a-table n (fun n)) (hash-ref a-table n))))))) Now I want to create a memoize-wrapper function like this: (define (memoize-wrapper function) (set! function (memoizer function))) And hopefully create a macro called def-memo which defines the function with the memoize-wrapper. eg. the macro could expand to (memoizer (define function-name arguments body ...) or something like that. So that I should be able to do : (def-memo (factorial n) (cond ((= n 1) 1) (else (* n (factorial (- n 1)))))) which should create a memoized version of the factorial instead of the normal slow one. My problem is that the The memoize-wrapper is not working properly, it doesnt call the memoized function but the original function. I have no idea how to write a define inside of the macro. How do I make sure that I can get variable lenght arguments and variable length body? How do I then define the function and wrap it around with the memoizer? Thanks a lot.

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  • Avoiding explicit recursion in Haskell

    - by Travis Brown
    The following simple function applies a given monadic function iteratively until it hits a Nothing, at which point it returns the last non-Nothing value. It does what I need, and I understand how it works. lastJustM :: (Monad m) => (a -> m (Maybe a)) -> a -> m a lastJustM g x = g x >>= maybe (return x) (lastJustM g) As part of my self-education in Haskell I'm trying to avoid explicit recursion (or at least understand how to) whenever I can. It seems like there should be a simple non-explicitly recursive solution in this case, but I'm having trouble figuring it out. I don't want something like a monadic version of takeWhile, since it could be expensive to collect all the pre-Nothing values, and I don't care about them anyway. I checked Hoogle for the signature and nothing shows up. The m (Maybe a) bit makes me think a monad transformer might be useful here, but I don't really have the intuitions I'd need to come up with the details (yet). It's probably either embarrassingly easy to do this or embarrassingly easy to see why it can't or shouldn't be done, but this wouldn't be the first time I've used self-embarrassment as a pedagogical strategy. Background: Here's a simplified working example for context: suppose we're interested in random walks in the unit square, but we only care about points of exit. We have the following step function: randomStep :: (Floating a, Ord a, Random a) => a -> (a, a) -> State StdGen (Maybe (a, a)) randomStep s (x, y) = do (a, gen') <- randomR (0, 2 * pi) <$> get put gen' let (x', y') = (x + s * cos a, y + s * sin a) if x' < 0 || x' > 1 || y' < 0 || y' > 1 then return Nothing else return $ Just (x', y') Something like evalState (lastJustM (randomStep 0.01) (0.5, 0.5)) <$> newStdGen will give us a new data point.

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