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  • extract associative array within an array in php

    - by I Like PHP
    i have an array like this Array ( [0] => Array ( [s_id] => 4 [si_id] => sec_1 [d_id] => dep_4 [s_name] => sec1 [s_location] => LA [s_visibility] => yes [s_created_date] => 1273639343 [s_last_updated_date] => 1273639343 [s_created_by] => someone [s_last_updated_by] => everyone ) ) now i want to extract array[0] into an array... means i want this Array ( [s_id] => 4 [si_id] => sec_1 [d_id] => dep_4 [s_name] => sec1 [s_location] => LA [s_visibility] => yes [s_created_date] => 1273639343 [s_last_updated_date] => 1273639343 [s_created_by] => someone [s_last_updated_by] => everyone ) how do i get above results?

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  • Populate array from vector

    - by Zag zag..
    Hi, I would like to populate an 2 dimensional array, from a vector. I think the best way to explain myself is to put some examples (with a array of [3,5] length). When vector is: [1, 0] [ [4, 3, 2, 1, 0], [4, 3, 2, 1, 0], [4, 3, 2, 1, 0] ] When vector is: [-1, 0] [ [0, 1, 2, 3, 4], [0, 1, 2, 3, 4], [0, 1, 2, 3, 4] ] When vector is: [-2, 0] [ [0, 0, 1, 1, 2], [0, 0, 1, 1, 2], [0, 0, 1, 1, 2] ] When vector is: [1, 1] [ [2, 2, 2, 1, 0], [1, 1, 1, 1, 0], [0, 0, 0, 0, 0] ] When vector is: [0, 1] [ [2, 2, 2, 2, 2], [1, 1, 1, 1, 1], [0, 0, 0, 0, 0] ] Have you got any ideas, a good library or a plan? Any comments are welcome. Thanks. Note: I consulted Ruby "Matrix" and "Vector" classes, but I don't see any way to use it in my way... Edit: In fact, each value is the number of cells (from the current cell to the last cell) according to the given vector. If we take the example where the vector is [-2, 0], with the value *1* (at array[2, 3]): array = [ [<0>, <0>, <1>, <1>, <2>], [<0>, <0>, <1>, <1>, <2>], [<0>, <0>, <1>, *1*, <2>] ] ... we could think such as: The vector [-2, 0] means that -2 is for cols and 0 is for rows. So if we are in array[2, 3], we can move 1 time on the left (left because 2 is negative) with 2 length (because -2.abs == 2). And we don't move on the top or bottom, because of 0 for rows.

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  • perl comparing 2 data file as array 2D for finding match one to one [migrated]

    - by roman serpa
    I'm doing a program that uses combinations of variables ( combiData.txt 63 rows x different number of columns) for analysing a data table ( j1j2_1.csv, 1000filas x 19 columns ) , to choose how many times each combination is repeated in data table and which rows come from (for instance, tableData[row][4]). I have tried to compile it , however I get the following message : Use of uninitialized value $val in numeric eq (==) at rowInData.pl line 34. Use of reference "ARRAY(0x1a2eae4)" as array index at rowInData.pl line 56. Use of reference "ARRAY(0x1a1334c)" as array index at rowInData.pl line 56. Use of uninitialized value in subtraction (-) at rowInData.pl line 56. Modification of non-creatable array value attempted, subscript -1 at rowInData.pl line 56. nothing This is my code: #!/usr/bin/perl use strict; use warnings; my $line_match; my $countTrue; open (FILE1, "<combiData.txt") or die "can't open file text1.txt\n"; my @tableCombi; while(<FILE1>) { my @row = split(' ', $_); push(@tableCombi, \@row); } close FILE1 || die $!; open (FILE2, "<j1j2_1.csv") or die "can't open file text1.txt\n"; my @tableData; while(<FILE2>) { my @row2 = split(/\s*,\s*/, $_); push(@tableData, \@row2); } close FILE2 || die $!; #function transform combiData.txt variable (position ) to the real value that i have to find in the data table. sub trueVal($){ my ($val) = $_[0]; if($val == 7){ return ('nonsynonymous_SNV'); } elsif( $val == 14) { return '1'; } elsif( $val == 15) { return '1';} elsif( $val == 16) { return '1'; } elsif( $val == 17) { return '1'; } elsif( $val == 18) { return '1';} elsif( $val == 19) { return '1';} else { print 'nothing'; } } #function IntToStr ( ) , i'm not sure if it is necessary) that transforms $ to strings , to use the function <eq> in the third loop for the array of combinations compared with the data array . sub IntToStr { return "$_[0]"; } for my $combi (@tableCombi) { $line_match = 0; for my $sheetData (@tableData) { $countTrue=0; for my $cell ( @$combi) { #my $temp =\$tableCombi[$combi][$cell] ; #if ( trueVal($tableCombi[$combi][$cell] ) eq $tableData[$sheetData][ $tableCombi[$combi][$cell] - 1 ] ){ #if ( IntToStr(trueVal($$temp )) eq IntToStr( $tableData[$sheetData][ $$temp-1] ) ){ if ( IntToStr(trueVal($tableCombi[$combi][$cell]) ) eq IntToStr($tableData[$sheetData][ $tableCombi[$combi][$cell] -1]) ){ $countTrue++;} if ($countTrue==@$combi){ $line_match++; #if ($line_match < 50){ print $tableData[$sheetData][4]." "; #} } } } print $line_match." \n"; }

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  • Create an array from mysql with column names and values [on hold]

    - by ScaZ
    i'm trying to create an array with PHP and MySQL, but i always get errors. The code i'm using function db_listar_usuarios(){ $link=db_connect(); $query = "select * from usuarios" or die("Problemas en el select: " . mysqli_error($link)); $result = $link->query($query); while($row = mysqli_fetch_assoc($result)) { $row['nombre'] . array(; foreach ($row as $col => $val) { $col => $val; } } } And what I want to create with this code is: array( 'john' => array('address' => 'st 123', 'age' => '25', 'surname' => 'doe'), 'ane' => array('address' => 'av 456', 'age'=> '32', 'surname' => 'smith'), ); To use then like something like this: private $contacts = db_listar_usuarios(); I use 2 files: functions.php and server.php server.php is a downloaded file example to do a REST API. Here are both of them. server.php - pastebin.com/5j54m1Mz functions.php - pastebin.com/N7jMhSBa Thank you in advance!

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  • What is the name of this array transformation?

    - by Brandon Tilley
    Start with an array of arrays; in this case, they are different lengths in order to demonstrate the technique, but they do not have to be. [[1,2,3,4], [5,6,7], [8,9,10], [11,12,13,14,15]] At the other end of the transformation, you have an array of arrays where the first array contains the first element from each of the original arrays, the second array contains the second element from each of the original arrays, and so on. [[1,5,8,11], [2,6,9,12], [3,7,10,13], [4,14], [15]] Is there a mathematical or CS term for this operation?

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  • How do boost operators work?

    - by FredOverflow
    boost::operators automatically defines operators like + based on manual implementations like += which is very useful. To generate those operators for T, one inherits from boost::operators<T> as shown by the boost example: class MyInt : boost::operators<MyInt> I am familiar with the CRTP pattern, but I fail to see how it works here. Specifically, I am not really inheriting any facilities since the operators aren't members. boost::operators seems to be completely empty, but I'm not very good at reading boost source code. Could anyone explain how this works in detail? Is this mechanism well-known and widely used?

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  • Boost Thread Hanging on _endthreadex

    - by FranticPedantic
    I think I am making a simple mistake, but since I noticed there are many boost experts here, I thought I would ask for help. I am trying to use boost threads(1_40) on windows xp. The main program loads a dll, starts the thread like so (note this is not in a class, the static does not mean static to a class but private to the file). static boost::thread network_thread; network_start() { // do network stuff until quit is signaled } DllClass::InitInstance() { network_thread = boost::thread(boost::bind<void>(network_start)); } DllClass::ExitInstance() { //signal quit (which works) //the following code is slightly verbose because I'm trying to figure out what's wrong try { if (network_thread.joinable() ) { network_thread.join(); } else { TRACE("Too late!"); } } catch (boost::thread_interrupted&) { TRACE("NET INTERRUPTED"); } } The problem is that the main thread is hanging on the join, and the network thread is hanging at the end of _endthreadex. What am I misunderstanding?

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  • Generating a reasonable ctags database for Boost

    - by Robert S. Barnes
    I'm running Ubuntu 8.04 and I ran the command: $ ctags -R --c++-kinds=+p --fields=+iaS --extra=+q -f ~/.vim/tags/stdlibcpp /usr/include/c++/4.2.4/ to generate a ctags database for the standard C++ library and STL ( libstdc++ ) on my system for use with the OmniCppComplete vim script. This gave me a very reasonable 4MB tags file which seems to work fairly well. However, when I ran the same command against the installed Boost headers: $ ctags -R --c++-kinds=+p --fields=+iaS --extra=+q -f ~/.vim/tags/boost /usr/include/boost/ I ended up with a 1.4 GB tags file! I haven't tried it yet, but that seems likes it's going to be too large to be useful. Is there a way to get a slimmer, more usable tags file for my installed Boost headers? Edit Just as a note, libstdc++ includes TR1, which has allot of Boost libs in it. So there must be something weird going on for libstdc++ to come out with a 4 MB tags file and Boost to end up with a 1.4 GB tags file.

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  • Compiling OpenSSL for boost asio for Microsoft Visual Studio 2010

    - by user560106
    I compiled boost with bjam, and then I compiled OpenSSL. Both of them work separately. I set up the links in Visual Studio 10 to point to my OpenSSL library directory. But when I attempt to compile example boost ssl asio programs I get 44 unresolved external linker errors like this one: 1testing.obj : error LNK2019: unresolved external symbol _SSLv23_server_method referenced in function "public: void __thiscall boost::asio::ssl::detail::openssl_context_service::create(struct ssl_ctx_st * &,enum boost::asio::ssl::context_base::method)" (?create@openssl_context_service@detail@ssl@asio@boost@@QAEXAAPAUssl_ctx_st@@W4method@context_base@345@@Z) Can you please give me step-by-step instructions on properly linking OpenSSL to boost? Thank you so much

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  • Modelling boost::Lockable with semaphore rather than mutex (previously titled: Unlocking a mutex fr

    - by dan
    I'm using the C++ boost::thread library, which in my case means I'm using pthreads. Officially, a mutex must be unlocked from the same thread which locks it, and I want the effect of being able to lock in one thread and then unlock in another. There are many ways to accomplish this. One possibility would be to write a new mutex class which allows this behavior. For example: class inter_thread_mutex{ bool locked; boost::mutex mx; boost::condition_variable cv; public: void lock(){ boost::unique_lock<boost::mutex> lck(mx); while(locked) cv.wait(lck); locked=true; } void unlock(){ { boost::lock_guard<boost::mutex> lck(mx); if(!locked) error(); locked=false; } cv.notify_one(); } // bool try_lock(); void error(); etc. } I should point out that the above code doesn't guarantee FIFO access, since if one thread calls lock() while another calls unlock(), this first thread may acquire the lock ahead of other threads which are waiting. (Come to think of it, the boost::thread documentation doesn't appear to make any explicit scheduling guarantees for either mutexes or condition variables). But let's just ignore that (and any other bugs) for now. My question is, if I decide to go this route, would I be able to use such a mutex as a model for the boost Lockable concept. For example, would anything go wrong if I use a boost::unique_lock< inter_thread_mutex for RAII-style access, and then pass this lock to boost::condition_variable_any.wait(), etc. On one hand I don't see why not. On the other hand, "I don't see why not" is usually a very bad way of determining whether something will work. The reason I ask is that if it turns out that I have to write wrapper classes for RAII locks and condition variables and whatever else, then I'd rather just find some other way to achieve the same effect. EDIT: The kind of behavior I want is basically as follows. I have an object, and it needs to be locked whenever it is modified. I want to lock the object from one thread, and do some work on it. Then I want to keep the object locked while I tell another worker thread to complete the work. So the first thread can go on and do something else while the worker thread finishes up. When the worker thread gets done, it unlocks the mutex. And I want the transition to be seemless so nobody else can get the mutex lock in between when thread 1 starts the work and thread 2 completes it. Something like inter_thread_mutex seems like it would work, and it would also allow the program to interact with it as if it were an ordinary mutex. So it seems like a clean solution. If there's a better solution, I'd be happy to hear that also. EDIT AGAIN: The reason I need locks to begin with is that there are multiple master threads, and the locks are there to prevent them from accessing shared objects concurrently in invalid ways. So the code already uses loop-level lock-free sequencing of operations at the master thread level. Also, in the original implementation, there were no worker threads, and the mutexes were ordinary kosher mutexes. The inter_thread_thingy came up as an optimization, primarily to improve response time. In many cases, it was sufficient to guarantee that the "first part" of operation A, occurs before the "first part" of operation B. As a dumb example, say I punch object 1 and give it a black eye. Then I tell object 1 to change it's internal structure to reflect all the tissue damage. I don't want to wait around for the tissue damage before I move on to punch object 2. However, I do want the tissue damage to occur as part of the same operation; for example, in the interim, I don't want any other thread to reconfigure the object in such a way that would make tissue damage an invalid operation. (yes, this example is imperfect in many ways, and no I'm not working on a game) So we made the change to a model where ownership of an object can be passed to a worker thread to complete an operation, and it actually works quite nicely; each master thread is able to get a lot more operations done because it doesn't need to wait for them all to complete. And, since the event sequencing at the master thread level is still loop-based, it is easy to write high-level master-thread operations, as they can be based on the assumption that an operation is complete when the corresponding function call returns. Finally, I thought it would be nice to use inter_thread mutex/semaphore thingies using RAII with boost locks to encapsulate the necessary synchronization that is required to make the whole thing work.

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  • Boost Regex throwing an error

    - by Srinivasa Varadan
    Hi ALL, I have the following error when I try to compile my code in g+ compiler using eclipse In function `ZSt19__iterator_categoryIPKSsENSt15iterator_traitsIT_E17iterator_categoryERKS3_': C:/Program Files (x86)/mingw/bin/../lib/gcc/mingw32/3.4.5/../../../../include/c++/3.4.5/bits/stl_algobase.h:(.text$_ZN5boost11basic_regexIcNS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEE6assignEPKcS7_j[boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::assign(char const*, char const*, unsigned int)]+0x22): undefined reference to `boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::do_assign(char const*, char const*, unsigned int)' collect2: ld returned 1 exit status Build error occurred, build is stopped All I have done is this statement boost::regex re("\s+"); along with the header #inlucde Could you kindly tell me how to proceed ?

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  • Linker Issues with boost::thread under linux using Eclipse and CMake

    - by OcularProgrammer
    I'm in the process of attempting to port some code across from PC to Ubuntu, and am having some issues due to limited experience developing under linux. We use CMake to generate all our build stuff. Under windows I'm making VS2010 projects, and under Linux I'm making Eclipse projects. I've managed to get my OpenCV stuff ported across successfully, but am having major headaches trying to port my threaded boost apps. Just so we're clear, the steps I have followed so-far on a clean Ubuntu 12 installation. (I've done 2 clean re-installs to try and fix potential library cock-ups, now I'm just giving up and asking): Install Eclipse and Eclipse CDT using my package manager Install CMake and CMake Gui using my package manager Install libboost-all-dev using my package manager So-far that's all I've done. I can create the eclipse project using CMake with no errors, so CMake is successfully finding my boost install. When I try and build through eclipse is when I get issues; The app I'm attempting to build uses boost::asio for some UDP I/O and boost::thread to create worker threads for the asio I/O services. I can successfully compile each module, but when I come to link I get spammed with errors such as: /usr/bin/c++ CMakeFiles/RE05DevelopmentDemo.dir/main.cpp.o CMakeFiles/RE05DevelopmentDemo.dir/RE05FusionListener/RE05FusionListener.cpp.o CMakeFiles/RE05DevelopmentDemo.dir/NewEye/NewEye.cpp.o -o RE05DevelopmentDemo -rdynamic -Wl,-Bstatic -lboost_system-mt -lboost_date_time-mt -lboost_regex-mt -lboost_thread-mt -Wl,-Bdynamic /usr/lib/gcc/x86_64-linux-gnu/4.6/../../../../lib/libboost_thread-mt.a(thread.o): In function `void boost::call_once<void (*)()>(boost::once_flag&, void (*)()) [clone .constprop.98]': make[2]: Leaving directory `/home/david/Code/Build/Support/RE05DevDemo' (.text+0xc8): undefined reference to `pthread_key_create' /usr/lib/gcc/x86_64-linux-gnu/4.6/../../../../lib/libboost_thread-mt.a(thread.o): In function `boost::this_thread::interruption_enabled()': (.text+0x540): undefined reference to `pthread_getspecific' make[1]: Leaving directory `/home/david/Code/Build/Support/RE05DevDemo' /usr/lib/gcc/x86_64-linux-gnu/4.6/../../../../lib/libboost_thread-mt.a(thread.o): In function `boost::this_thread::disable_interruption::disable_interruption()': (.text+0x570): undefined reference to `pthread_getspecific' /usr/lib/gcc/x86_64-linux-gnu/4.6/../../../../lib/libboost_thread-mt.a(thread.o): In function `boost::this_thread::disable_interruption::disable_interruption()': (.text+0x59f): undefined reference to `pthread_getspecific' Some Gotchas that I have collected from other StackOverflow posts and have already checked: The boost libs are all present at /usr/lib I am not getting any compile errors for inability to find the boost headers, so they must be getting found. I am trying to link statically, but I believe eclipse should be passing the correct arguments to make that happen since my CMakeLists.txt includes SET(Boost_USE_STATIC_LIBS ON) I'm officially out of ideas here, I have tried doing local builds of boost and a bunch of other stuff with no more success. I even re-installed Ubuntu to ensure I haven't completely fracked the libs directories and links with multiple weird versions or anything else. Any help would be muchly appreciated.

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  • Using concurrently 2 versions of boost

    - by idimba
    I'm using RHEL 5.3, which is shipped with gcc 4.1.2 and boost 1.33. There're some features I want, that are missing in the boost 1.33. Therefore the thought was to upgrade to fresh boost release 1.43. Is it possible to use concurrently some header-only library(s) from boost 1.43 and the rest from 1.33? For example I want to use unorded_map, which is missing in boost 1.33. Is it possible to use concurrently binary boost libraries from different releases?

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  • Recursing data into a 2 dimensional array in PHP 5

    - by user315699
    I'm getting bamboozled by "for each" loops and two dimensional arrays, and I'm a php newb so please bear with me (and ignore any variables with the word "image" - it's all about the mp3s, I just didn't change it from the xml tutorial) I found a php function on the net that list files in a directory, the output of which is: Array ( [0] = audio/1.mp3 [1] = audio/2.mp3 [2] = audio/3.mp3 [3] = audio/4.mp3 [4] = audio/5.mp3 ) As expected. And another that lists some info about mp3 files. $mp3datafile = 'audio/1.mp3'; $m = new mp3file($mp3datafile); $mp3dataArray = $m-get_metadata(); print_r($mp3dataArray); unset($mp3dataArray); The output of which is Array ( [Filesize] = 31972 [Encoding] = CBR [etc] ) In order to automatically build RSS for a podcast, I need to generate XML for each item. So far so good. This is how I'm making the xml foreach ($imagearray as $key = $val) { $tnsoundfile = $xml_generator-addChild('item'); $tnsoundfile-addChild('title', $podcasttitle); $enclosure = $tnsoundfile-addChild('enclosure'); $enclosure-addAttribute('url', $val); // that's the filename $enclosure-addAttribute('length', $mp3dataArray[Filesize]); // << Length is file length, not time. But later I also need $mp3dataArray[Length mm:ss] for duration tag. $enclosure-addAttribute('type', 'audio/mpeg'); $tnsoundfile-addChild('guid', $path_to_image_dir.'/'.$val); } (The above has been truncated, I realise it's not proper xml right now, but it was just to show what was going on). Perfect. But I need to do it for as many files as there are in the directory. So, I have an array of the names of the files in the directory in $mp3data And, I have an array of mp3 data in $mp3dataArray from one iteration of the get_metadata() function. If I do the following, then I get a nice list of the mp3 data of the 5 files in the directory: foreach ($mp3data as $key = $val) { $mp3datafile = $val; $m = new mp3file($mp3datafile); $mp3dataArray = $m-get_metadata(); print_r($mp3dataArray); unset($mp3dataArray); } As expected. Where I'm struggling, and have been for most of the day in spite of reading many forums and tutorials, is how to populate the "second dimension" of the array, so that it goes through 1,2,3,4 and 5.mp3 (or however many there are), extracts the metadata, then allows me to use it in the xml section above. Here's what I have foreach ($mp3data as $key = $val) { $mp3datafile = $val; $m = new mp3file($mp3datafile); $mp3dataArray = $m-get_metadata(); $mp3testarray = array($mp3dataArray); } print_r($mp3dataArray); Shouldn't that line print_r($mp3dataArray); give me a nice list of 5 lots of mp3 data, in the way it did when I recursed through the loop as before? Cos this is driving me nuts! It must be something so simple, and any help would be greatly appreciated. Thank you in advance.

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  • Help with Boost Grammar

    - by Decmanc04
    I have been using the following win32 console code to try to parse a B Machine Grammar embedded within C++ using Boost Spirit grammar template. I am a relatively new Boost user. The code compiles, but when I run the .exe file produced by VC++2008, the program partially parses the input file. I believe the problem is with my grammar definition or the functions attached as semantic atctions. The code is given below: // BIFAnalyser.cpp : Defines the entry point for the console application. // // /*============================================================================= Copyright (c) Temitope Jos Onunkun 2010 http://www.dcs.kcl.ac.uk/pg/onun/ Use, modification and distribution is subject to the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) =============================================================================*/ //////////////////////////////////////////////////////////////////////////// // // // B Machine parser using the Boost "Grammar" and "Semantic Actions". // // // //////////////////////////////////////////////////////////////////////////// #include <boost/spirit/core.hpp> #include <boost/tokenizer.hpp> #include <iostream> #include <string> #include <fstream> #include <vector> #include <utility> /////////////////////////////////////////////////////////////////////////////////////////// using namespace std; using namespace boost::spirit; /////////////////////////////////////////////////////////////////////////////////////////// // // Semantic actions // //////////////////////////////////////////////////////////////////////////// vector<string> strVect; namespace { //semantic action function on individual lexeme void do_noint(char const* str, char const* end) { string s(str, end); if(atoi(str)) { ; } else { strVect.push_back(s); cout << "PUSH(" << s << ')' << endl; } } //semantic action function on addition of lexemes void do_add(char const*, char const*) { cout << "ADD" << endl; for(vector<string>::iterator vi = strVect.begin(); vi < strVect.end(); ++vi) cout << *vi << " "; } //semantic action function on subtraction of lexemes void do_subt(char const*, char const*) { cout << "SUBTRACT" << endl; for(vector<string>::iterator vi = strVect.begin(); vi < strVect.end(); ++vi) cout << *vi << " "; } //semantic action function on multiplication of lexemes void do_mult(char const*, char const*) { cout << "\nMULTIPLY" << endl; for(vector<string>::iterator vi = strVect.begin(); vi < strVect.end(); ++vi) cout << *vi << " "; cout << "\n"; } //semantic action function on division of lexemes void do_div(char const*, char const*) { cout << "\nDIVIDE" << endl; for(vector<string>::iterator vi = strVect.begin(); vi < strVect.end(); ++vi) cout << *vi << " "; } //semantic action function on simple substitution void do_sSubst(char const* str, char const* end) { string s(str, end); //use boost tokenizer to break down tokens typedef boost::tokenizer<boost::char_separator<char> > Tokenizer; boost::char_separator<char> sep("-+/*:=()"); // default char separator Tokenizer tok(s, sep); Tokenizer::iterator tok_iter = tok.begin(); pair<string, string > dependency; //create a pair object for dependencies //save first variable token in simple substitution dependency.first = *tok.begin(); //create a vector object to store all tokens vector<string> dx; // for( ; tok_iter != tok.end(); ++tok_iter) //save all tokens in vector { dx.push_back(*tok_iter ); } vector<string> d_hat; //stores set of dependency pairs string dep; //pairs variables as string object for(int unsigned i=1; i < dx.size()-1; i++) { dependency.second = dx.at(i); dep = dependency.first + "|->" + dependency.second + " "; d_hat.push_back(dep); } cout << "PUSH(" << s << ')' << endl; for(int unsigned i=0; i < d_hat.size(); i++) cout <<"\n...\n" << d_hat.at(i) << " "; cout << "\nSIMPLE SUBSTITUTION\n"; } //semantic action function on multiple substitution void do_mSubst(char const* str, char const* end) { string s(str, end); //use boost tokenizer to break down tokens typedef boost::tokenizer<boost::char_separator<char> > Tok; boost::char_separator<char> sep("-+/*:=()"); // default char separator Tok tok(s, sep); Tok::iterator tok_iter = tok.begin(); // string start = *tok.begin(); vector<string> mx; for( ; tok_iter != tok.end(); ++tok_iter) //save all tokens in vector { mx.push_back(*tok_iter ); } mx.push_back("END\n"); //add a marker "end" for(unsigned int i=0; i<mx.size(); i++) { // if(mx.at(i) == "END" || mx.at(i) == "||" ) // break; // else if( mx.at(i) == "||") // do_sSubst(str, end); // else // { // do_sSubst(str, end); // } cout << "\nTokens ... " << mx.at(i) << " "; } cout << "PUSH(" << s << ')' << endl; cout << "MULTIPLE SUBSTITUTION\n"; } } //////////////////////////////////////////////////////////////////////////// // // Simple Substitution Grammar // //////////////////////////////////////////////////////////////////////////// // Simple substitution grammar parser with integer values removed struct Substitution : public grammar<Substitution> { template <typename ScannerT> struct definition { definition(Substitution const& ) { multi_subst = (simple_subst [&do_mSubst] >> +( str_p("||") >> simple_subst [&do_mSubst]) ) ; simple_subst = (Identifier >> str_p(":=") >> expression)[&do_sSubst] ; Identifier = alpha_p >> +alnum_p//[do_noint] ; expression = term >> *( ('+' >> term)[&do_add] | ('-' >> term)[&do_subt] ) ; term = factor >> *( ('*' >> factor)[&do_mult] | ('/' >> factor)[&do_div] ) ; factor = lexeme_d[( (alpha_p >> +alnum_p) | +digit_p)[&do_noint]] | '(' >> expression >> ')' | ('+' >> factor) ; } rule<ScannerT> expression, term, factor, Identifier, simple_subst, multi_subst ; rule<ScannerT> const& start() const { return multi_subst; } }; }; //////////////////////////////////////////////////////////////////////////// // // Main program // //////////////////////////////////////////////////////////////////////////// int main() { cout << "************************************************************\n\n"; cout << "\t\t...Machine Parser...\n\n"; cout << "************************************************************\n\n"; // cout << "Type an expression...or [q or Q] to quit\n\n"; //prompt for file name to be input cout << "Please enter a filename...or [q or Q] to quit:\n\n "; char strFilename[256]; //file name store as a string object cin >> strFilename; ifstream inFile(strFilename); // opens file object for reading //output file for truncated machine (operations only) Substitution elementary_subst; // Simple substitution parser object string str, next; // inFile.open(strFilename); while (inFile >> str) { getline(cin, next); str += next; if (str.empty() || str[0] == 'q' || str[0] == 'Q') break; parse_info<> info = parse(str.c_str(), elementary_subst, space_p); if (info.full) { cout << "\n-------------------------\n"; cout << "Parsing succeeded\n"; cout << "\n-------------------------\n"; } else { cout << "\n-------------------------\n"; cout << "Parsing failed\n"; cout << "stopped at: \": " << info.stop << "\"\n"; cout << "\n-------------------------\n"; } } cout << "Please enter a filename...or [q or Q] to quit\n"; cin >> strFilename; return 0; } The contents of the file I tried to parse, which I named "mf7.txt" is given below: debt:=(LoanRequest+outstandingLoan1)*20 || newDebt := loanammount-paidammount The output when I execute the program is: ************************************************************ ...Machine Parser... ************************************************************ Please enter a filename...or [q or Q] to quit: c:\tplat\mf7.txt PUSH(LoanRequest) PUSH(outstandingLoan1) ADD LoanRequest outstandingLoan1 MULTIPLY LoanRequest outstandingLoan1 PUSH(debt:=(LoanRequest+outstandingLoan1)*20) ... debt|->LoanRequest ... debt|->outstandingLoan1 SIMPLE SUBSTITUTION Tokens ... debt Tokens ... LoanRequest Tokens ... outstandingLoan1 Tokens ... 20 Tokens ... END PUSH(debt:=(LoanRequest+outstandingLoan1)*20) MULTIPLE SUBSTITUTION ------------------------- Parsing failedstopped at: ": " ------------------------- My intention is to capture only the variables in the file, which I managed to do up to the "||" string. Clearly, the program is not parsing beyond the "||" string in the input file. I will appreciate assistance to fix the grammar. SOS, please.

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  • LWJGL Voxel game, glDrawArrays

    - by user22015
    I've been learning about 3D for a couple days now. I managed to create a chunk (8x8x8). Add optimization so it only renders the active and visible blocks. Then I added so it only draws the faces which don't have a neighbor. Next what I found from online research was that it is better to use glDrawArrays to increase performance. So I restarted my little project. Render an entire chunck, add optimization so it only renders active and visible blocks. But now I want to add so it only draws the visible faces while using glDrawArrays. This is giving me some trouble with calling glDrawArrays because I'm passing a wrong count parameter. > # A fatal error has been detected by the Java Runtime Environment: > # > # EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x0000000006e31a03, pid=1032, tid=3184 > # Stack: [0x00000000023a0000,0x00000000024a0000], sp=0x000000000249ef70, free space=1019k Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code) C [ig4icd64.dll+0xa1a03] Java frames: (J=compiled Java code, j=interpreted, Vv=VM code) j org.lwjgl.opengl.GL11.nglDrawArrays(IIIJ)V+0 j org.lwjgl.opengl.GL11.glDrawArrays(III)V+20 j com.vox.block.Chunk.render()V+410 j com.vox.ChunkManager.render()V+30 j com.vox.Game.render()V+11 j com.vox.GameHandler.render()V+12 j com.vox.GameHandler.gameLoop()V+15 j com.vox.Main.main([Ljava/lang/StringV+13 v ~StubRoutines::call_stub public class Chunk { public final static int[] DIM = { 8, 8, 8}; public final static int CHUNK_SIZE = (DIM[0] * DIM[1] * DIM[2]); Block[][][] blocks; private int index; private int vBOVertexHandle; private int vBOColorHandle; public Chunk(int index) { this.index = index; vBOColorHandle = GL15.glGenBuffers(); vBOVertexHandle = GL15.glGenBuffers(); blocks = new Block[DIM[0]][DIM[1]][DIM[2]]; for(int x = 0; x < DIM[0]; x++){ for(int y = 0; y < DIM[1]; y++){ for(int z = 0; z < DIM[2]; z++){ blocks[x][y][z] = new Block(); } } } } public void render(){ Block curr; FloatBuffer vertexPositionData2 = BufferUtils.createFloatBuffer(CHUNK_SIZE * 6 * 12); FloatBuffer vertexColorData2 = BufferUtils.createFloatBuffer(CHUNK_SIZE * 6 * 12); int counter = 0; for(int x = 0; x < DIM[0]; x++){ for(int y = 0; y < DIM[1]; y++){ for(int z = 0; z < DIM[2]; z++){ curr = blocks[x][y][z]; boolean[] neightbours = validateNeightbours(x, y, z); if(curr.isActive() && !neightbours[6]) { float[] arr = curr.createCube((index*DIM[0]*Block.BLOCK_SIZE*2) + x*2, y*2, z*2, neightbours); counter += arr.length; vertexPositionData2.put(arr); vertexColorData2.put(createCubeVertexCol(curr.getCubeColor())); } } } } vertexPositionData2.flip(); vertexPositionData2.flip(); FloatBuffer vertexPositionData = BufferUtils.createFloatBuffer(vertexColorData2.position()); FloatBuffer vertexColorData = BufferUtils.createFloatBuffer(vertexColorData2.position()); for(int i = 0; i < vertexPositionData2.position(); i++) vertexPositionData.put(vertexPositionData2.get(i)); for(int i = 0; i < vertexColorData2.position(); i++) vertexColorData.put(vertexColorData2.get(i)); vertexColorData.flip(); vertexPositionData.flip(); GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, vBOVertexHandle); GL15.glBufferData(GL15.GL_ARRAY_BUFFER, vertexPositionData, GL15.GL_STATIC_DRAW); GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, 0); GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, vBOColorHandle); GL15.glBufferData(GL15.GL_ARRAY_BUFFER, vertexColorData, GL15.GL_STATIC_DRAW); GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, 0); GL11.glPushMatrix(); GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, vBOVertexHandle); GL11.glVertexPointer(3, GL11.GL_FLOAT, 0, 0L); GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, vBOColorHandle); GL11.glColorPointer(3, GL11.GL_FLOAT, 0, 0L); System.out.println("Counter " + counter); GL11.glDrawArrays(GL11.GL_LINE_LOOP, 0, counter); GL11.glPopMatrix(); //blocks[r.nextInt(DIM[0])][2][r.nextInt(DIM[2])].setActive(false); } //Random r = new Random(); private float[] createCubeVertexCol(float[] CubeColorArray) { float[] cubeColors = new float[CubeColorArray.length * 4 * 6]; for (int i = 0; i < cubeColors.length; i++) { cubeColors[i] = CubeColorArray[i % CubeColorArray.length]; } return cubeColors; } private boolean[] validateNeightbours(int x, int y, int z) { boolean[] bools = new boolean[7]; bools[6] = true; bools[6] = bools[6] && (bools[0] = y > 0 && y < DIM[1]-1 && blocks[x][y+1][z].isActive());//top bools[6] = bools[6] && (bools[1] = y > 0 && y < DIM[1]-1 && blocks[x][y-1][z].isActive());//bottom bools[6] = bools[6] && (bools[2] = z > 0 && z < DIM[2]-1 && blocks[x][y][z+1].isActive());//front bools[6] = bools[6] && (bools[3] = z > 0 && z < DIM[2]-1 && blocks[x][y][z-1].isActive());//back bools[6] = bools[6] && (bools[4] = x > 0 && x < DIM[0]-1 && blocks[x+1][y][z].isActive());//left bools[6] = bools[6] && (bools[5] = x > 0 && x < DIM[0]-1 && blocks[x-1][y][z].isActive());//right return bools; } } public class Block { public static final float BLOCK_SIZE = 1f; public enum BlockType { Default(0), Grass(1), Dirt(2), Water(3), Stone(4), Wood(5), Sand(6), LAVA(7); int BlockID; BlockType(int i) { BlockID=i; } } private boolean active; private BlockType type; public Block() { this(BlockType.Default); } public Block(BlockType type){ active = true; this.type = type; } public float[] getCubeColor() { switch (type.BlockID) { case 1: return new float[] { 1, 1, 0 }; case 2: return new float[] { 1, 0.5f, 0 }; case 3: return new float[] { 0, 0f, 1f }; default: return new float[] {0.5f, 0.5f, 1f}; } } public float[] createCube(float x, float y, float z, boolean[] neightbours){ int counter = 0; for(boolean b : neightbours) if(!b) counter++; float[] array = new float[counter*12]; int offset = 0; if(!neightbours[0]){//top array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; } if(!neightbours[1]){//bottom array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; } if(!neightbours[2]){//front array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; } if(!neightbours[3]){//back array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; } if(!neightbours[4]){//left array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; } if(!neightbours[5]){//right array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = x*BLOCK_SIZE + BLOCK_SIZE; array[offset++] = y*BLOCK_SIZE - BLOCK_SIZE; array[offset++] = z*BLOCK_SIZE - BLOCK_SIZE; } return Arrays.copyOf(array, offset); } public boolean isActive() { return active; } public void setActive(boolean active) { this.active = active; } public BlockType getType() { return type; } public void setType(BlockType type) { this.type = type; } } I highlighted the code I'm concerned about in this following screenshot: - http://imageshack.us/a/img820/7606/18626782.png - (Not allowed to upload images yet) I know the code is a mess but I'm just testing stuff so I wasn't really thinking about it.

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  • Decode sparse json array to php array

    - by Isaac Sutherland
    I can create a sparse php array (or map) using the command: $myarray = array(10=>'hi','test20'=>'howdy'); I want to serialize/deserialize this as JSON. I can serialize it using the command: $json = json_encode($myarray); which results in the string {"10":"hi","test20":"howdy"}. However, when I deserialize this and cast it to an array using the command: $mynewarray = (array)json_decode($json); I seem to lose any mappings with keys which were not valid php identifiers. That is, mynewarray has mapping 'test20'=>'howdy', but not 10=>'hi' nor '10'=>'hi'. Is there a way to preserve the numerical keys in a php map when converting to and back from json using the standard json_encode / json_decode functions?

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  • Get the current array key in a multi dimensional array

    - by johlton
    Hi *, I have a session array *$_SESSION['cart']* with some items in it. The structure ist like this (via *print_r*): Array ( [2-1] => Array ( [color] => 7 [articlenumber] => WRG70 10 [quantity] => 1 [price] => 17.50 ) [3-8] => Array ( [color] => 2 [articlenumber] => QRG50 02 [quantity] => 1 [price] => 13.50 ) ) Looping over the values for display is fine ... foreach($_SESSION['cart'] as $item_array) { foreach($item_array as $item => $value) { echo $value . ' | '; } } ... since it results in something like this: 7 | WRG70 10 | 1 | 17.50 | 2 | QRG50 02 | 1 | 13.50 | But Now: How can I output the matching key (e.g. '2-1') as well? I tried some array functions like key() & current but couldn't get it to work (one of these days). Any quick hint on this? Thanks a lot and best from Berlin Fabian

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  • Get usable array from a curl response, which is formatted as a php array

    - by Mint
    $ch = curl_init("url"); curl_setopt($ch, CURLOPT_POST, 1); curl_setopt($ch, CURLOPT_POSTFIELDS, "test"); curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1); curl_setopt($ch, CURLOPT_HEADER, 0); curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); $outputArray = curl_exec($ch); Then $outputArray will contain: Array ( [0] => Array ( [r1] => test response [r2] => 4 [r3] => 32 ) ) So I would think PHP can see that it's an array and treat it as such, but when I do something like echo $outputCode[0][r_title]."\n"; it gives an error: PHP Fatal error: Cannot use string offset as an array in /www/test.php on line 75 (line 75 being the echo one just above) What am I doing wrong?

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  • php array to jquery array to qTip plugin.

    - by jp577
    Hi I'm trying to get a PHP array to use in some jquery script using the qTip plugin. This is my array: $descqtip[ ] = array('name' => ''.$name.'', 'description' => ''.$description.''); Here is my jquery code: <script type="text/javascript"> $(document).ready(function() { var description = <?php echo json_encode($descqtip)?>; $('#homepage_catgames h2').each(function(i){ $(this).qtip({ content: description }) }); }); </script> I know the above doesn't work, but i'm stuck on trying to get the description variable in each part of the array to their own individual tooltip. Can anyone help me? Thanks

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  • Array of an array (Database)

    - by Anne Mah Li'en
    I am trying to print out an array of an array from database Below are my codes. I am able to retrieve all the values from the first array. But error occurs when I am trying to retrieve the 2nd array from database. <% ArrayList<Questionnaire> allCategories =QuestionnaireController.getQuestionnaireByCategoryAll(); for(int i=0;i<allCategories.size();i++){ Questionnaire allCategoriesQuestionnaire=allCategories.get(i); out.println("<div class=\"silverheader\">" + "<a href= \"\">" + allCategoriesQuestionnaire.getCategory() + "</a>" + "</div>" + "<div class=\"submenu\">" + "ArrayList<Questionnaire> CategoriesSustainability =QuestionnaireController.getQuestionnaireByCategorySustainability();" + out.println(CategoriesSustainability.get(0).getCategory()); + "<br />" + "</div>"); } %>

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  • array and array_view from amp.h

    - by Daniel Moth
    This is a very long post, but it also covers what are probably the classes (well, array_view at least) that you will use the most with C++ AMP, so I hope you enjoy it! Overview The concurrency::array and concurrency::array_view template classes represent multi-dimensional data of type T, of N dimensions, specified at compile time (and you can later access the number of dimensions via the rank property). If N is not specified, it is assumed that it is 1 (i.e. single-dimensional case). They are rectangular (not jagged). The difference between them is that array is a container of data, whereas array_view is a wrapper of a container of data. So in that respect, array behaves like an STL container, whereas the closest thing an array_view behaves like is an STL iterator (albeit with random access and allowing you to view more than one element at a time!). The data in the array (whether provided at creation time or added later) resides on an accelerator (which is specified at creation time either explicitly by the developer, or set to the default accelerator at creation time by the runtime) and is laid out contiguously in memory. The data provided to the array_view is not stored by/in the array_view, because the array_view is simply a view over the real source (which can reside on the CPU or other accelerator). The underlying data is copied on demand to wherever the array_view is accessed. Elements which differ by one in the least significant dimension of the array_view are adjacent in memory. array objects must be captured by reference into the lambda you pass to the parallel_for_each call, whereas array_view objects must be captured by value (into the lambda you pass to the parallel_for_each call). Creating array and array_view objects and relevant properties You can create array_view objects from other array_view objects of the same rank and element type (shallow copy, also possible via assignment operator) so they point to the same underlying data, and you can also create array_view objects over array objects of the same rank and element type e.g.   array_view<int,3> a(b); // b can be another array or array_view of ints with rank=3 Note: Unlike the constructors above which can be called anywhere, the ones in the rest of this section can only be called from CPU code. You can create array objects from other array objects of the same rank and element type (copy and move constructors) and from other array_view objects, e.g.   array<float,2> a(b); // b can be another array or array_view of floats with rank=2 To create an array from scratch, you need to at least specify an extent object, e.g. array<int,3> a(myExtent);. Note that instead of an explicit extent object, there are convenience overloads when N<=3 so you can specify 1-, 2-, 3- integers (dependent on the array's rank) and thus have the extent created for you under the covers. At any point, you can access the array's extent thought the extent property. The exact same thing applies to array_view (extent as constructor parameters, incl. convenience overloads, and property). While passing only an extent object to create an array is enough (it means that the array will be written to later), it is not enough for the array_view case which must always wrap over some other container (on which it relies for storage space and actual content). So in addition to the extent object (that describes the shape you'd like to be viewing/accessing that data through), to create an array_view from another container (e.g. std::vector) you must pass in the container itself (which must expose .data() and a .size() methods, e.g. like std::array does), e.g.   array_view<int,2> aaa(myExtent, myContainerOfInts); Similarly, you can create an array_view from a raw pointer of data plus an extent object. Back to the array case, to optionally initialize the array with data, you can pass an iterator pointing to the start (and optionally one pointing to the end of the source container) e.g.   array<double,1> a(5, myVector.begin(), myVector.end()); We saw that arrays are bound to an accelerator at creation time, so in case you don’t want the C++ AMP runtime to assign the array to the default accelerator, all array constructors have overloads that let you pass an accelerator_view object, which you can later access via the accelerator_view property. Note that at the point of initializing an array with data, a synchronous copy of the data takes place to the accelerator, and then to copy any data back we'll see that an explicit copy call is required. This does not happen with the array_view where copying is on demand... refresh and synchronize on array_view Note that in the previous section on constructors, unlike the array case, there was no overload that accepted an accelerator_view for array_view. That is because the array_view is simply a wrapper, so the allocation of the data has already taken place before you created the array_view. When you capture an array_view variable in your call to parallel_for_each, the copy of data between the non-CPU accelerator and the CPU takes place on demand (i.e. it is implicit, versus the explicit copy that has to happen with the array). There are some subtleties to the on-demand-copying that we cover next. The assumption when using an array_view is that you will continue to access the data through the array_view, and not through the original underlying source, e.g. the pointer to the data that you passed to the array_view's constructor. So if you modify the data through the array_view on the GPU, the original pointer on the CPU will not "know" that, unless one of two things happen: you access the data through the array_view on the CPU side, i.e. using indexing that we cover below you explicitly call the array_view's synchronize method on the CPU (this also gets called in the array_view's destructor for you) Conversely, if you make a change to the underlying data through the original source (e.g. the pointer), the array_view will not "know" about those changes, unless you call its refresh method. Finally, note that if you create an array_view of const T, then the data is copied to the accelerator on demand, but it does not get copied back, e.g.   array_view<const double, 5> myArrView(…); // myArrView will not get copied back from GPU There is also a similar mechanism to achieve the reverse, i.e. not to copy the data of an array_view to the GPU. copy_to, data, and global copy/copy_async functions Both array and array_view expose two copy_to overloads that allow copying them to another array, or to another array_view, and these operations can also be achieved with assignment (via the = operator overloads). Also both array and array_view expose a data method, to get a raw pointer to the underlying data of the array or array_view, e.g. float* f = myArr.data();. Note that for array_view, this only works when the rank is equal to 1, due to the data only being contiguous in one dimension as covered in the overview section. Finally, there are a bunch of global concurrency::copy functions returning void (and corresponding concurrency::copy_async functions returning a future) that allow copying between arrays and array_views and iterators etc. Just browse intellisense or amp.h directly for the full set. Note that for array, all copying described throughout this post is deep copying, as per other STL container expectations. You can never have two arrays point to the same data. indexing into array and array_view plus projection Reading or writing data elements of an array is only legal when the code executes on the same accelerator as where the array was bound to. In the array_view case, you can read/write on any accelerator, not just the one where the original data resides, and the data gets copied for you on demand. In both cases, the way you read and write individual elements is via indexing as described next. To access (or set the value of) an element, you can index into it by passing it an index object via the subscript operator. Furthermore, if the rank is 3 or less, you can use the function ( ) operator to pass integer values instead of having to use an index object. e.g. array<float,2> arr(someExtent, someIterator); //or array_view<float,2> arr(someExtent, someContainer); index<2> idx(5,4); float f1 = arr[idx]; float f2 = arr(5,4); //f2 ==f1 //and the reverse for assigning, e.g. arr(idx[0], 7) = 6.9; Note that for both array and array_view, regardless of rank, you can also pass a single integer to the subscript operator which results in a projection of the data, and (for both array and array_view) you get back an array_view of rank N-1 (or if the rank was 1, you get back just the element at that location). Not Covered In this already very long post, I am not going to cover three very cool methods (and related overloads) that both array and array_view expose: view_as, section, reinterpret_as. We'll revisit those at some point in the future, probably on the team blog. Comments about this post by Daniel Moth welcome at the original blog.

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  • Array of Arrays in C#

    - by Betamoo
    I need to know how to initialize array of arrays in C#.. I know that there exist multidimensional array, but I think I do not need that in my case! I tried this code.. but could not know how to initialize with initializer list.. double[][] a=new double[2][];// ={{1,2},{3,4}}; Thank you PS: If you wonder why I use it: I need data structure that when I call obj[0] it returns an array.. I know it is strange.. Thanks

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  • Counting viable sublist lengths from an array.

    - by Ben B.
    This is for a genetic algorithm fitness function, so it is important I can do this as efficiently as possible, as it will be repeated over and over. Lets say there is a function foo(int[] array) that returns true if the array is a "good" array and false if the array is a "bad" array. What makes it good or bad does not matter here. Given the full array [1,6,8,9,5,11,45,16,9], lets say that subarray [1,6,8] is a "good" array and [9,5,11,45] is a "good" array. Furthermore [5,11,45,16,9] is a "good" array, and also the longest "good" subarray. Notice that while [9,5,11,45] is a "good" array, and [5,11,45,16,9] is a "good" array, [9,5,11,45,16,9] is a "bad" array. We wants the length counts of all "good" arrays, but not subarrays of "good" arrays. Furthermore, as described above, a "good" array might begin in the middle of another "good" array, but the combination of the two might be a "bad" array.

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  • Boost Thread Synchronization

    - by Dave18
    I don't see synchronized output when i comment the the line wait(1) in thread(). can I make them run at the same time (one after another) without having to use 'wait(1)'? #include <boost/thread.hpp> #include <iostream> void wait(int seconds) { boost::this_thread::sleep(boost::posix_time::seconds(seconds)); } boost::mutex mutex; void thread() { for (int i = 0; i < 100; ++i) { wait(1); mutex.lock(); std::cout << "Thread " << boost::this_thread::get_id() << ": " << i << std::endl; mutex.unlock(); } } int main() { boost::thread t1(thread); boost::thread t2(thread); t1.join(); t2.join(); }

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