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

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]);
 }

[Walter Roberson]

You could mexCallMATLAB "uint32" or as appropriate.

I noticed though that you are using find(). It seems most likely that you intend to use the results as indices. Array Indexing in GPU is not efficient. Logical indexing should be faster in most cases, if I understand correctly.

[wei zhang]

@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.

[Walter Roberson]

Sorry, I am not familiar with those routines.