我正在开发一个程序，该程序将一个充满无符号字符的大型二进制文件（> 80GB）读入std :: vector，然后在该向量中的元素块上运行计算。我想通过让独立的线程同时在向量的不同部分运行这些计算来加速，并在最后结合结果。
这些线程都应该将它们的计算结果存储在一对2维std :: vector中，我试图将它作为引用传递给线程函数调用。我可以将这一切都用于通用函数调用，但是当我尝试使用std :: thread启动它时，我得到以下编译错误：
In file included from /usr/include/c++/4.8/thread:39:0,
from test.cpp:12:
/usr/include/c++/4.8/functional: In instantiation of ‘struct std::_Bind_simple<int (*(long long unsigned int, long long unsigned int, std::vector<unsigned char>, std::vector<std::vector<long double> >, std::vector<std::vector<long long unsigned int> >))(long long unsigned int, long long unsigned int, std::vector<unsigned char>&, std::vector<std::vector<long double> >&, std::vector<std::vector<long long unsigned int> >&)>’:
/usr/include/c++/4.8/thread:137:47: required from ‘std::thread::thread(_Callable&&, _Args&& ...) [with _Callable = int (&)(long long unsigned int, long long unsigned int, std::vector<unsigned char>&, std::vector<std::vector<long double> >&, std::vector<std::vector<long long unsigned int> >&); _Args = {long long unsigned int&, long long unsigned int&, std::vector<unsigned char, std::allocator<unsigned char> >&, std::vector<std::vector<long double, std::allocator<long double> >, std::allocator<std::vector<long double, std::allocator<long double> > > >&, std::vector<std::vector<long long unsigned int, std::allocator<long long unsigned int> >, std::allocator<std::vector<long long unsigned int, std::allocator<long long unsigned int> > > >&}]’
test.cpp:44:130: required from here
/usr/include/c++/4.8/functional:1697:61: error: no type named ‘type’ in ‘class std::result_of<int (*(long long unsigned int, long long unsigned int, std::vector<unsigned char>, std::vector<std::vector<long double> >, std::vector<std::vector<long long unsigned int> >))(long long unsigned int, long long unsigned int, std::vector<unsigned char>&, std::vector<std::vector<long double> >&, std::vector<std::vector<long long unsigned int> >&)>’
typedef typename result_of<_Callable(_Args...)>::type result_type;
^
/usr/include/c++/4.8/functional:1727:9: error: no type named ‘type’ in ‘class std::result_of<int (*(long long unsigned int, long long unsigned int, std::vector<unsigned char>, std::vector<std::vector<long double> >, std::vector<std::vector<long long unsigned int> >))(long long unsigned int, long long unsigned int, std::vector<unsigned char>&, std::vector<std::vector<long double> >&, std::vector<std::vector<long long unsigned int> >&)>’
_M_invoke(_Index_tuple<_Indices...>)
^
我使用g ++ 4.8.2在Linux中编译：
g++ -Wall test.cpp -o test -std=c++0x
非常感谢任何反馈。非常感谢！
我的代码如下：
#include <iostream>
#include <vector>
#include <fstream>
#include <thread>
#include <cstdlib>
#include <cmath>
int functionToRun (unsigned long long startingNum, unsigned long long endingNum, std::vector<unsigned char>& mainReadCountVector, std::vector<std::vector<long double>>& threadPWP, std::vector<std::vector<unsigned long long int>>& threadWeightings);
int main(int argc, const char * argv[])
{
int numThreads = 32;
std::streampos size;
std::ifstream file ("data.bin", std::ios::in|std::ios::binary|std::ios::ate);
if (file.is_open()) {
// Create and populate the vector that holds all the data in the binary file
size = file.tellg();
file.seekg (0, std::ios::beg);
std::vector<unsigned char> data(size);
file.read((char*) &data[0], size);
file.close();
// The resulting calculations within each thread will be stored in a 2D vector that looks like std::vector<std::vector<long double>> calc1(272, std::vector<long double>(272,0)) and std::vector<std::vector<unsigned long long int>> calc2(272, std::vector<unsigned long long int>(272,0))
// Create one of these vectors for each of the threads by making a 3D vector:
std::vector<std::vector<std::vector<long double>>> calc1(numThreads, std::vector<std::vector<long double>> (272, std::vector<long double> (272,0) ) ); //calc1[0] is the first 2D array for the first thread, etc...
std::vector<std::vector<std::vector<unsigned long long int>>> calc2(numThreads, std::vector<std::vector<unsigned long long int> > (272, std::vector<unsigned long long int> (272,0) ) );
//Launch a group of threads
std::vector<std::thread> threadsVec;
for (int threadRunning = 0; threadRunning < numThreads; threadRunning++) {
unsigned long long firstNum = threadRunning * 1000000;
unsigned long long secondNum = (threadRunning * 1000000) + 1000000 - 1;
threadsVec.push_back(std::thread(functionToRun, firstNum, secondNum, data, calc1[threadRunning], calc2[threadRunning]));
}
// Wait on threads to finish
for (int i = 0; i < numThreads; ++i) {
threadsVec[i].join();
}
// Now aggregate the results of the threads
std::vector<std::vector<long double>> calc1Sum(272, std::vector<long double>(272,0));
std::vector<std::vector<long double>> calc2Sum(272, std::vector<long double>(272,0));
for (int element = 0; element < 272; element++) {
for (int comparisonElement = 0; comparisonElement <= element; comparisonElement++) {
for (int threadVector = 0; threadVector <= numThreads; threadVector++) {
calc1Sum[element][comparisonElement] += calc1[threadVector][element][comparisonElement];
calc2Sum[element][comparisonElement] += calc2[threadVector][element][comparisonElement];
}
}
}
} else std::cout << "Unable to open data.bin";
return 0;
}
int functionToRun (unsigned long long startingNum, unsigned long long endingNum, std::vector<unsigned char>& mainDataVector, std::vector<std::vector<long double>>& calc1ret, std::vector<std::vector<unsigned long long int>>& calc2ret) {
int internalData[272];
for (unsigned long long dataSpot = startingNum; dataSpot < endingNum; dataSpot++) {
for (int ind1 = 0; ind1 < 272; ind1++) {
unsigned long long firstIndex = dataSpot * 544 + 2 * ind1;
unsigned long long secondIndex = dataSpot * 544 + 2 * ind1 + 1;
internalData[ind1] = mainDataVector[firstIndex] + mainDataVector[secondIndex];
for (int ind2 = 0; ind2 <= ind1; ind2++) {
calc1ret[ind1][ind2] = internalData[ind1] + internalData[ind2];
calc2ret[ind1][ind2] = internalData[ind1] / (std::pow(internalData[ind2],2));
}
}
}
return 0;
}