How to change the class of mxArray double to int in c mex ?

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wei zhang 2021-2-14

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https://ww2.mathworks.cn/matlabcentral/answers/744817-how-to-change-the-class-of-mxarray-double-to-int-in-c-mex

评论： Walter Roberson 2021-2-15

Hi,

I am trying to convert a double class mxArray to int. I don't know how to do that. My c code is like below. I would like to create the mxGPUArray "row" in int class, which is the row index of matrix A. In my code, the type of "row" is double.

#include "mex.h"
#include "gpu/mxGPUArray.h"
#define	A prhs[0]
void mexFunction(int nlhs, mxArray * plhs[], int nrhs, const mxArray * prhs[])
{
    mxArray *tmp[3];
    mexCallMATLAB(3,tmp,1,&A,"find");
    mxGPUArray const *row = mxGPUCreateFromMxArray(tmp[1]);
 }

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wei zhang 2021-2-15

@Walter Roberson Thank you for your comment. 1. The uint32 is good to convert data type. 2. I use find function to convert sparse matrix A into COO format. My final goal is to use HYB format of sparse matrix in conjugated gradient method solving Ax = b.To convert matrix A to HYB format, I plan ot use cusparseXcoo2csr and cusparseDcsr2hyb function in cusparse, which transfer sparse matrix from COO to CSR, then to HYB. That is why I need the indices. If you have any suggestion, I would like to know. Cudamex coding is some hard for me.