使用c ++和mex输出矩阵 [英] Output a matrix with c++ and mex

问题描述

我的c ++代码有问题。我想返回一个矩阵的k维度从我的cpp程序到Matlab。

I have a problem with my c++ code. I want to return a matrix of k-dimensions from my cpp program to Matlab.

我想传递的矩阵存储在 all_data 中，是一个大小为（npoints + 1）x ndims 。

The matrix I want to pass is stored in all_data, and is a matrix of size (npoints+1) x ndims.

我一直在寻找如何做到这一点，我想出了：

I have been looking how to do that, and I have come up with:

    //send back points
    vector< vector <double> > indexes = mxGetPr(plhs[0]);
    for (int i=0; i < (npoints1+1); i++)
            for (int j=0; j < ndims1; j++)
                indexes[ i ][ j ] = all_data[ i ][ j ];

但它不工作，因为 all_data 是向量<向量<双>> 变量，并且matlab说：

But it does not work, as all_data is a vector<vector<double>> variable, and matlab says:

error: conversion from 'double*' to non-scalar type 
'std::vector<std::vector<double, std::allocator<double> >, 
std::allocator<std::vector<double, 
std::allocator<double> > > >' requested

有人可以帮助我吗？非常感谢！

Can someone help me out? Thanks a lot!

推荐答案

看起来像mxGetPr会返回一个指向一个双精度数组的指针，矢量的矢量。

It looks like mxGetPr is returning you a pointer to an array of doubles and you are assigning it to a vector of vectors.

这应该可以工作：

double* indexes = mxGetPr(plhs[0]);

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