C++中向量的叉积
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Cross product of vectors in C++
提问by user1507246
As a part of a program that I'm writing, I need to find the cross product of a vector of doubles and a vector of complex doubles. I've written a function that I feel should do this, but when I call it, I get the following error:
作为我正在编写的程序的一部分，我需要找到双精度向量和复双精度向量的叉积。我写了一个我觉得应该这样做的函数，但是当我调用它时，我收到以下错误：
error: no matching function for call to ‘CrossProduct1D(std::vector< double, std::allocator<double> >&, std::vector<std::complex<double>, std::allocator<std::complex<double> > >&)'
Here is my code:
这是我的代码：
#include <iostream>
#include <fstream>
#include <sstream>
#include <string>
#include <vector>
#include <math.h>
#include <complex>
using namespace std;
//1D cross product
template <typename T>
vector<T> CrossProduct1D(vector<T> const &a, vector<T> const &b)
{
vector<T> r (a.size());
r[0] = a[1]*b[2]-a[2]*b[1];
r[1] = a[2]*b[0]-a[0]*b[2];
r[2] = a[0]*b[1]-a[1]*b[0];
return r;
}
//::::::::importing data from text::::::::::
vector<string> ezivec;
ezivec.reserve(4000);
string ezidat("ez.i.txt");
ifstream ezifile;
ezifile.open(ezidat.c_str());
if(!ezifile.is_open())
{
cerr<<"Error opening file : "<<ezidat.c_str()<<endl;
return -1;
}
string ezistr; //store lines in vector
while(getline(ezifile, ezistr, ';'))
{
ezivec.push_back(ezistr);
}
ezifile.close();
//Converting from vector of strings to vector of floats
vector<double> ezi (ezivec.size());
for(int i = 0; i < ezivec.size(); ++i)
{
ezi[i] = string_to_T<double>(ezivec[i]);
}
//
vector<string> ezrvec;
ezrvec.reserve(4000);
string ezrdat("ez.r.txt");
ifstream ezrfile;
ezrfile.open(ezrdat.c_str());
if(!ezrfile.is_open())
{
cerr<<"Error opening file : "<<ezrdat.c_str()<<endl;
return -1;
}
string ezrstr;
while(getline(ezrfile, ezrstr, ';'))
{
ezrvec.push_back(ezrstr);
}
ezrfile.close();
vector<double> ezr (ezrvec.size());
for(int i = 0; i < ezrvec.size(); ++i)
{
ezr[i] = string_to_T<double>(ezrvec[i]);
}
//:::::::defining vectors:::::::
vector<vector<complex<double> > > E0 (ezi.size(), vector<complex<double> > (3));
for(int i = 0; i < ezi.size(); i++)
{
E0[i][0].real() = 0.0;
E0[i][0].imag() = 0.0;
E0[i][1].real() = 0.0;
E0[i][1].imag() = 0.0;;
E0[i][2].real() = ezr[i];
E0[i][2].imag() = ezi[i];
}
vector<double> n_a (3);
n_a[0] = 1.0;
n_a[1] = 0.0;
n_a[2] = 0.0;
//:::::::calling cross product:::::::
for(int j = 1; j < jmax; j++)
{
M[j] = CrossProduct1D(n_a, E0[j]);
}
"ez.i.txt" and "ez.r.txt" are semicolon-delimited text files of 4000 numbers.
“ez.i.txt”和“ez.r.txt”是4000个数字的分号分隔的文本文件。
回答by CB Bailey
Your template function is parameterized on a single type, T, and takes two vector<T>but you are trying to pass it two different types of vectors so there is no single Tthat can be selected.
您的模板函数被参数化为单一类型，T并且需要两个，vector<T>但您试图将两种不同类型的向量传递给它，因此没有T可以选择的单一类型。
You could have two template parameters, e.g.
你可以有两个模板参数，例如
template<class T, class U> CrossProduct1D(std::vector<T> const& a,
std::vector<U> const& b)
