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Search found 65 results on 3 pages for 'haiyuan zhang'.

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  • Is it possible ot mix named pipe with select in perl

    - by Haiyuan Zhang
    I need to write a daemon that supposed to have one TCP socket and one named pipe. Usually if I need to implement a multi IO server with "pure" sockets, the select based multi-IO model is always the one I will choose. so does anyone of you have ever used named pipe in select or you can just tell me it is impossible. thanks in advance.

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  • how to handle "unknown error" in perl module compilation

    - by Haiyuan Zhang
    when I try to use a "third part module" in my perl script, I got some error message like "unknown error, compilation failed in require at ... line xxx" nothing else and the line mentioned in the error message is exact the same line I "use the module"... my question is: are there any good practice to handle this situation? like a list to check or something else. thanks in advance.

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  • how to adjust the default width of taglist window in vim

    - by Haiyuan Zhang
    The default width of taglist window is too narrow for me and sometimes I can't see the whole function name in the window so I'd like to adujct the width of the window. I know use ctr-w > or ctr-w < I can adjust the window manually , but really want to change the default value of the taglisst window. so how I can actually do it ? thansk in advance.

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  • how to store a file handle in perl class

    - by Haiyuan Zhang
    please look at the following code first. #! /usr/bin/perl package foo; sub new { my $pkg = shift; my $self = {}; my $self->{_fd} = undef; bless $self, $pkg; return $self; } sub Setfd { my $self = shift; my $fd = shift; $self_->{_fd} = $fd; } sub write { my $self = shift; print $self->{_fd} "hello word"; } my $foo = new foo; My intention is to store a file handle within a class using hash. the file handle is undefined at first, but can be initilized afterwards by calling Setfd function. then write can be called to actually write string "hello word" to a file indicated by the file handle, supposed that the file handle is the result of a success "write" open. but, perl compiler just complains that there are syntax error in the "print" line. can anyone of you tells me what's wrong here? thanks in advance.

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  • why can't i bind ipv6 socket to a linklocal address

    - by Haiyuan Zhang
    #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <netdb.h> #include <stdio.h> void error(char *msg) { perror(msg); exit(0); } int main(int argc, char *argv[]) { int sock, length, fromlen, n; struct sockaddr_in6 server; struct sockaddr_in6 from; int portNr = 5555; char buf[1024]; length = sizeof (struct sockaddr_in6); sock=socket(AF_INET6, SOCK_DGRAM, 0); if (sock < 0) error("Opening socket"); bzero((char *)&server, length); server.sin6_family=AF_INET6; server.sin6_addr=in6addr_any; server.sin6_port=htons(portNr); inet_pton( AF_INET6, "fe80::21f:29ff:feed:2f7e", (void *)&server.sin6_addr.s6_addr); //inet_pton( AF_INET6, "::1", (void *)&server.sin6_addr.s6_addr); if (bind(sock,(struct sockaddr *)&server,length)<0) error("binding"); fromlen = sizeof(struct sockaddr_in6); while (1) { n = recvfrom(sock,buf,1024,0,(struct sockaddr *)&from,&fromlen); if (n < 0) error("recvfrom"); write(1,"Received a datagram: ",21); write(1,buf,n); n = sendto(sock,"Got your message\n",17, 0,(struct sockaddr *)&from,fromlen); if (n < 0) error("sendto"); } } when I compile and run the above code I got : binding: Invalid argument and if change to bind the ::1 and leave other thing unchanged in the source code, the code works! so could you tell me what's wrong with my code ? thanks in advance.

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  • how to find files in a given branch

    - by Haiyuan Zhang
    I noticed that when doing code view, people here in my company usually just give the branch in which his work is done, and nothing else. So I guess there must be a easy way to find out all the files that has a version in the given branch which is the same thing to find all the files that has been the changed. Yes, I don't know the expected "easy way" to find files in certain branch, so need your help and thanks in advance.

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  • Is it possible to mix a named pipe with select in perl?

    - by Haiyuan Zhang
    I need to write a daemon that supposed to have one TCP socket and one named pipe. Usually if I need to implement a multi IO server with "pure" sockets, the select based multi-IO model is always the one I will choose. so does anyone of you have ever used named pipe in select or you can just tell me it is impossible. thanks in advance.

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  • why does perl allow mutually "use" relationship between modules

    - by Haiyuan Zhang
    let's say there two modules mutualy use each othe as: package a; use b; sub p {} 1; package b; use a; 1; I think symatically it's wrong to wrote code like the above code, cus the two modules will endlessly copy each other's code to themselves...but I can successfully run the following code, which makes me very surprised. so could any of you explain all of this to me? #! /usr/bin/perl use a; a->p();

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  • are there any good timer implementation in perl

    - by Haiyuan Zhang
    I'm looking for good timer implementation in perl. The situation I met is like: I need to keep track of I/O activities of many files and for thoes files keep untouched for enough time a remove action will be taken upon them, so an efficient timer implementation is really vital for the app I'm involved right now. To avoid recreate the wheel, ask you guys for help first.

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  • how to install a file handle in perl class

    - by Haiyuan Zhang
    please looku up the following code first. #! /usr/bin/perl package foo; sub new { my $pkg = shift; my $self = {}; my $self->{_fd} = undef; bless $self, $pkg; return $self; } sub Setfd { my $self = shift; my $fd = shift; $self_->{_fd} = $fd; } sub write { my $self = shift; print $self->{_fd} "hello word"; } my $foo = new foo; My intention is to store a file handle within a class using hash. the file handle is undefined at first, but can be initilized afterwards by calling Setfd function. then write can be called to actually write string "hello word" to a file indicated by the file handle, supposed that the file handle is the result of a success "write" open. but, perl compiler just complains that there are syntax error in the "print" line. can anyone of you tells me what's wrong here? thanks in advance.

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  • why doesn't perl sort the hash key in numeric order ?

    - by Haiyuan Zhang
    #!/usr/bin/perl use strict; use warnings; my %hash; foreach ( 1 .. 10 ) { $hash{$_} = $_; } foreach ( sort(keys %hash) ) { print $_ . ": " . "$hash{$_}" . "\n" ; } execute the above code, the result is as below : 1: 1 10: 10 2: 2 3: 3 4: 4 5: 5 6: 6 7: 7 8: 8 9: 9 Yes, I expect "10: 10" to be the last one taht is printed . So I just need someone to explain why perl give me surprise in this case.

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  • How can I store and access a filehandle in a Perl class?

    - by Haiyuan Zhang
    please look at the following code first. #! /usr/bin/perl package foo; sub new { my $pkg = shift; my $self = {}; my $self->{_fd} = undef; bless $self, $pkg; return $self; } sub Setfd { my $self = shift; my $fd = shift; $self_->{_fd} = $fd; } sub write { my $self = shift; print $self->{_fd} "hello word"; } my $foo = new foo; My intention is to store a file handle within a class using hash. the file handle is undefined at first, but can be initilized afterwards by calling Setfd function. then write can be called to actually write string "hello word" to a file indicated by the file handle, supposed that the file handle is the result of a success "write" open. but, perl compiler just complains that there are syntax error in the "print" line. can anyone of you tells me what's wrong here? thanks in advance.

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  • Why does Perl allow mutual "use" relationships between modules?

    - by Haiyuan Zhang
    Let's say there are two modules that mutually use each other: package a; use b; sub p {} 1; package b; use a; 1; I think that it is systematically wrong to write code like the above, because the two modules will endlessly copy each other's code to themselves, but I can successfully run the following code, which makes me very surprised. Could any of you explain all of this to me? #! /usr/bin/perl use a; a->p();

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  • jquery dynatree class methods

    - by Jj Zhang
    I'm a new user of dynatree plugin. When I read the documentation, I found the list of tree and node class member functions, such as tree.getRoot(), node.countChildren(). However, when I tried to use them, it complained that no such methods were found. Here is a sample code I am testing with: var tree = ("#test").dynatree(treeData); var rootNode = tree.getRoot(); //not working var rootNode2 = ("#test").dynatree("getRoot"); //this works var numChildren = rootNode2.countChildren(); //not working Help please. Thanks. -JJ

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  • Why does my co-worker see a different Project file (*.csproj) using Visual Source Safe

    - by Leo Zhang
    Hello everybody, I met a problem which is very strange, my company uses Visual Source Safe to control version,but I found that my team's different member see the same .csproj file in VSS is not the same, it's very strange,can you help me? thanks!! there is a file named IPRA.WinUi.Sal.Sra.csproj in VSS: when Tom log on ,the file 'IPRA.WinUi.Sal.Sra.csproj' is : <Reference Include="Ark.Client.WinUi, Version=2.0.0.0, Culture=neutral, processorArchitecture=MSIL"> <SpecificVersion>False</SpecificVersion> <HintPath>..\ARAF\BusinessFramework\Ark.Client.WinUi.dll</HintPath> </Reference> <Reference Include="Ark.Common.Business, Version=1.0.0.0, Culture=neutral, processorArchitecture=MSIL" /> <Reference Include="Ark.Controls.Business, Version=0.0.0.0, Culture=neutral, processorArchitecture=MSIL"> <SpecificVersion>False</SpecificVersion> <HintPath>..\ARAF\SystemFramework\Ark.Controls.Business.dll</HintPath> </Reference> But when leo log on,the same file 'IPRA.WinUi.Sal.Sra.csproj' is : <Reference Include="Ark.Client.WinUi, Version=2.0.0.0, Culture=neutral, processorArchitecture=MSIL"> <SpecificVersion>False</SpecificVersion> <HintPath>..\ARAF\BusinessFramework\Ark.Client.WinUi.dll</HintPath> </Reference> <Reference Include="Ark.Common.Business, Version=1.0.0.0, Culture=neutral, processorArchitecture=MSIL" /> <SpecificVersion>False</SpecificVersion> <HintPath>..\ARAF\BusinessFramework\Ark.Controls.WinUi.dll</HintPath> <Reference Include="Ark.Controls.Business, Version=0.0.0.0, Culture=neutral, processorArchitecture=MSIL"> <SpecificVersion>False</SpecificVersion> <HintPath>..\ARAF\SystemFramework\Ark.Controls.Business.dll</HintPath> </Reference>

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  • How to drag item out from Iframe and drop onto parent

    - by ethan.zhang
    Hi, I have a folder tree view on the left page which was in a tag, left page was the iframe container which contain the file list, when I want to drag the files out from the iframe, I got a headache. no matter the containment option was set to 'parent' or 'window', I just can't drag out elements in the iframe container can any one help on this?

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  • push_back of STL list got bad performance?

    - by Leon Zhang
    I wrote a simple program to test STL list performance against a simple C list-like data structure. It shows bad performance at "push_back()" line. Any comments on it? $ ./test2 Build the type list : time consumed -> 0.311465 Iterate over all items: time consumed -> 0.00898 Build the simple C List: time consumed -> 0.020275 Iterate over all items: time consumed -> 0.008755 The source code is: #include <stdexcept> #include "high_resolution_timer.hpp" #include <list> #include <algorithm> #include <iostream> #define TESTNUM 1000000 /* The test struct */ struct MyType { int num; }; /* * C++ STL::list Test */ typedef struct MyType* mytype_t; void myfunction(mytype_t t) { } int test_stl_list() { std::list<mytype_t> mylist; util::high_resolution_timer t; /* * Build the type list */ t.restart(); for(int i = 0; i < TESTNUM; i++) { mytype_t aItem = (mytype_t) malloc(sizeof(struct MyType)); if(aItem == NULL) { printf("Error: while malloc\n"); return -1; } aItem->num = i; mylist.push_back(aItem); } std::cout << " Build the type list : time consumed -> " << t.elapsed() << std::endl; /* * Iterate over all item */ t.restart(); std::for_each(mylist.begin(), mylist.end(), myfunction); std::cout << " Iterate over all items: time consumed -> " << t.elapsed() << std::endl; return 0; } /* * a simple C list */ struct MyCList; struct MyCList{ struct MyType m; struct MyCList* p_next; }; int test_simple_c_list() { struct MyCList* p_list_head = NULL; util::high_resolution_timer t; /* * Build it */ t.restart(); struct MyCList* p_new_item = NULL; for(int i = 0; i < TESTNUM; i++) { p_new_item = (struct MyCList*) malloc(sizeof(struct MyCList)); if(p_new_item == NULL) { printf("ERROR : while malloc\n"); return -1; } p_new_item->m.num = i; p_new_item->p_next = p_list_head; p_list_head = p_new_item; } std::cout << " Build the simple C List: time consumed -> " << t.elapsed() << std::endl; /* * Iterate all items */ t.restart(); p_new_item = p_list_head; while(p_new_item->p_next != NULL) { p_new_item = p_new_item->p_next; } std::cout << " Iterate over all items: time consumed -> " << t.elapsed() << std::endl; return 0; } int main(int argc, char** argv) { if(test_stl_list() != 0) { printf("ERROR: error at testcase1\n"); return -1; } if(test_simple_c_list() != 0) { printf("ERROR: error at testcase2\n"); return -1; } return 0; }

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  • How to update the original InfoPath form from within Workflow?

    - by Allen.Zhang
    Hi All, I have created an InfoPath form (e.g. Form_ExpenseReport) for collect data from end users, and a number of task forms (also InfoPath form, e.g. TaskForm_1, TaskForm_2) for my state machine workflow use. The users want to see all the comments of Task forms (TaskForm_1 & TaskForm_2) in the original IP form (Form_ExpenseReport). How can I update the first form from within workflow? Can anybody give me some tips? My environment: MOSS 2007 Enterprise license VS 2008

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  • Initialize a static member ( an array) in C++

    - by Jimmy zhang
    I intended to create a class which only have static members and static functions. One of the member variable is an array. Would it be possible to initialize it without using constructors? I am having lots of linking errors right now... Class A{ public: static char a[128]; static void do_something(); } How would you initialize a[128]? Why can't I initialize a[128] by directly specifying its value like in C? a[128={1,2,3,...};

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  • approximating log10[x^k0 + k1]

    - by Yale Zhang
    Greetings. I'm trying to approximate the function Log10[x^k0 + k1], where .21 < k0 < 21, 0 < k1 < ~2000, and x is integer < 2^14. k0 & k1 are constant. For practical purposes, you can assume k0 = 2.12, k1 = 2660. The desired accuracy is 5*10^-4 relative error. This function is virtually identical to Log[x], except near 0, where it differs a lot. I already have came up with a SIMD implementation that is ~1.15x faster than a simple lookup table, but would like to improve it if possible, which I think is very hard due to lack of efficient instructions. My SIMD implementation uses 16bit fixed point arithmetic to evaluate a 3rd degree polynomial (I use least squares fit). The polynomial uses different coefficients for different input ranges. There are 8 ranges, and range i spans (64)2^i to (64)2^(i + 1). The rational behind this is the derivatives of Log[x] drop rapidly with x, meaning a polynomial will fit it more accurately since polynomials are an exact fit for functions that have a derivative of 0 beyond a certain order. SIMD table lookups are done very efficiently with a single _mm_shuffle_epi8(). I use SSE's float to int conversion to get the exponent and significand used for the fixed point approximation. I also software pipelined the loop to get ~1.25x speedup, so further code optimizations are probably unlikely. What I'm asking is if there's a more efficient approximation at a higher level? For example: Can this function be decomposed into functions with a limited domain like log2((2^x) * significand) = x + log2(significand) hence eliminating the need to deal with different ranges (table lookups). The main problem I think is adding the k1 term kills all those nice log properties that we know and love, making it not possible. Or is it? Iterative method? don't think so because the Newton method for log[x] is already a complicated expression Exploiting locality of neighboring pixels? - if the range of the 8 inputs fall in the same approximation range, then I can look up a single coefficient, instead of looking up separate coefficients for each element. Thus, I can use this as a fast common case, and use a slower, general code path when it isn't. But for my data, the range needs to be ~2000 before this property hold 70% of the time, which doesn't seem to make this method competitive. Please, give me some opinion, especially if you're an applied mathematician, even if you say it can't be done. Thanks.

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