我有1, 2, ..., n个向量,每个向量都有超过10000个元素,我需要获取这些向量的笛卡尔积。我已经有了一段代码,它可以工作,但只适用于1000个元素和4个向量以下。
我想将笛卡尔积写入文件,但如果输出文件大于1GB,我会得到"terminate called after throwing an instance of 'std::bad_alloc' what(): std::bad_alloc"的错误。
我的主要问题是,如何解决这个内存分配错误?
这是我代码的可运行片段:
我想将笛卡尔积写入文件,但如果输出文件大于1GB,我会得到"terminate called after throwing an instance of 'std::bad_alloc' what(): std::bad_alloc"的错误。
我的主要问题是,如何解决这个内存分配错误?
这是我代码的可运行片段:
#include <iostream>
#include <vector>
#include <algorithm>
#include <time.h>
#include <fstream>
#include <math.h>
using namespace std;
vector<double> makeVectorByRange(double min, double max, double step){
vector<double> out = {};
for( ; min <= max; min+=step){
out.push_back(min);
}
return out;
}
void cart_product_solve_and_write_to_file (const vector<vector<double>>& inpV) {
vector<vector<double>> out = {{}};
std::ofstream outputFile;
std::fixed;
for (auto& u : inpV) {
vector<vector<double>> r;
r.clear();
for (auto& x : out) {
//make/open file, append
outputFile.open ("out.csv", std::ofstream::out | std::ofstream::app);
outputFile.precision(8);
for (auto y : u) {
r.push_back(x);
r.back().push_back(y);
if( r.back().size() == inpV.size() ){
// write the input parameters of griewank to file
for(double asd : r.back()){
outputFile << asd << ";";
}
outputFile << "; \n";
outputFile << std::flush;
r.back().clear();
}
}
//close file
outputFile.close();
}
out.swap(r);
}
}
// Pure cartesian product. This function returns the cartesian product as a vector, but if the input vectors are too big, it has an error
/*
vector < vector<double> > cartesian_product (const vector< vector<double> >& inpV) {
vector< vector<double> > out = {{}};
for (auto& u : inpV) {
vector< vector<double> > r;
for (auto& x : out) {
for (auto y : u) {
r.push_back(x);
r.back().push_back(y);
}
}
out.swap(r);
}
return out;
}
*/
int main(){
clock_t tStart = clock();
// it works
// const vector<vector<int> > test ={ {0,1,2,3,4}, {5,6,7}, {8,9,10,11,12,13} };
// vector<vector<int> > cart_prod = cartesian_product(test);
vector <vector<double> > test = {};
test.push_back( makeVectorByRange( 0, 0.5, 0.001) );
test.push_back( makeVectorByRange( 0, 0.5, 0.001) );
test.push_back( makeVectorByRange( 0, 0.5, 0.001) );
cart_product_solve_and_write_to_file(test);
printf("Time taken: %.6fs\n", (double)(clock() - tStart)/CLOCKS_PER_SEC);
return 0;
}