mxGetDimensions returning incorrect values

조회 수: 15(최근 30일)
Jake 2012년 9월 20일
댓글: Artur MKRTCHYAN 2021년 5월 28일
I'm having a problem getting a mex file to run properly, and I was able to isolate the culprit as mxGetDimensions. For a matrix with dimensions MxNxL (in MATLAB), the function is returning the dimensions as Mx0xN. The relevant portion of the code follows. It's part of a code that will be run on the GPU but the problem occurs before I even do anything with the GPU.
#include "cuda.h"
#include "mex.h"
#include "math.h"
/*Main mex function*/
void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
int L,N,M,dims,gridDim_y,i;
const int *dim_array;
double *vUoldr, *vUoldi, *vUnewr, *vUnewi;
float *fvUoldr, *fvUoldi;
/*GPU variables:*/
float *Uoldr_gpu, *Uoldi_gpu;
/*Find the dimensions of the input cube*/
dims = (int)mxGetNumberOfDimensions(prhs[0]);
dim_array = (const int*)mxGetDimensions(prhs[0]);
M = dim_array[0];
N = dim_array[1];
L = dim_array[2];
printf("%d %d %d %d\n",dims,M, N, L);
In case something in my compilation is the issue here are the commands I'm using to compile:
!/usr/local/cuda/bin/nvcc -c -m64 -arch=sm_30 -Xcompiler -fPIC -I /Applications/
mex -largeArrayDims test.o
and my MATLAB version is 2011a on Mac OS 10.7.4. Any ideas would be helpful as I'm sort of stumped at this point.
  댓글 수: 1
Jan 2012년 9월 21일
@Jake: You use a meaningful title, useful tags (I add some others), you have spent time to isolate the problem and describe it clearly. The question contains the required code, though it is not formatted perfectly (I mark the code and hit the "{} Code" button for the last piece of perfection). You show the compile command, which can be useful for Mex problems and finally you mention the Matlab an OS version. Thanks for asking a good question! +1

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채택된 답변

Jan 2012년 9월 21일
편집: Jan 2012년 9월 22일
This fails on 64 bit machines, which use 32 bit for type INT:
dims = (int)mxGetNumberOfDimensions(prhs[0]);
dim_array = (const int*) mxGetDimensions(prhs[0]);
Better and working under 32 and 64 bit:
const mwSize *dim_array, dims;
dims = mxGetNumberOfDimensions(prhs[0]);
dim_array = mxGetDimensions(prhs[0]); // No casting needed, thanks James
  댓글 수: 6
Artur MKRTCHYAN 2021년 5월 28일
Thanks a lot !!

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추가 답변(1개)

Malcolm Lidierth
Malcolm Lidierth 2012년 9월 21일
Is N correct? I am rusty with mex but with -largeArrayDims, mxGetDimensions returns size_t results. See MATLAB docs for mwSize


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