mex从mex函数将向量从c ++传输到matlab [英] mex transferring a vector from c++ to matlab from mex function

问题描述

我试图通过用C ++编写一些函数并使用mex接口集成它们来加速我的Matlab程序.我在c ++中的向量中得到了结果.我想将其传输到MATLAB中的数组. 我知道我应该重定向

I am trying to speeden up my Matlab program by writing a few functions in C++ and using the mex interface to integrate them. I got my results in a vector in c++. I want to transfer it to an array in MATLAB. I know i should redirect

 plhs[0] to the vector 

但是我不知道该怎么做.

but i am not getting how exactly should I do it.

推荐答案

完成类似操作后，我将手动封送数据，以免C ++例程完成后将其释放.这是一个基本轮廓:

When I've done similar things, I manually marshal the data so that it won't be freed when the C++ routine is completed. Here's a basic outline:

#include <vector>
#include "mex.h"

mxArray * getMexArray(const std::vector<double>& v){
    mxArray * mx = mxCreateDoubleMatrix(1,v.size(), mxREAL);
    std::copy(v.begin(), v.end(), mxGetPr(mx));
    return mx;
}

void mexFunction(int nlhs, mxArray *plhs[ ], int nrhs, const mxArray *prhs[ ]) {
    std::vector<double> v;

    v.push_back(0);
    v.push_back(1);
    v.push_back(2);
    v.push_back(3);

    plhs[0] = getMexArray(v);

}

如果我将其另存为test.cpp，然后在该目录中打开matlab，则请执行以下操作:

If I save this as test.cpp and then open matlab in that directory, I do the following:

>> mex test.cpp
>> test

ans =

      0     1     2     3

这是预期的输出.希望这是一个很好的起点-您可能需要内联它，但是我不确定这样做的好处.顺便说一句，如果您还没有签出 matx mex帮助，那真是太棒了资源.

which is the expected output. Hopefully that is a good starting point - you may want to inline it, but I'm not sure of the benefit. Btw, if you haven't checked out the matlab mex help, it is a great resource.

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