MATLAB: Problem with mxGetScalar in mex function cuda

mex-functionmxgtscalar

Hi *,
i've three different files: main.m makeOperator.m makeOperator_A.cu
In main.m:
global DICTIONARY
load('data.mat');
A = makeOperator();
x = rand( size(A,2), 1, 'double' );
R = A*x;
In makeOperator.m:
classdef makeOperator
properties
methods
..
function v = mtimes( obj, x )
global DICTIONARY
..
v = makeOperator_A( DICTIONARY);
end
..
end
In makeOperator_A.cu:
void mexFunction(int nlhs, mxArray *plhs[],int nrhs, const mxArray *prhs[]) {
mxArray* tmp;
..
tmp = mxGetField(prhs[0],0,"nV");
nV = mxGetScalar(tmp);
..
}
DICTIONARY is in data.mat. DICTIONARY is a struct and nV is a field of a struct
Whit mxGetScalar(tmp) i obtain nV=0 instead of nV=72 that is the true value of nV saved in DICTIONARY.nV
Why?
Thanks,
Davide

Best Answer

If MATLAB prints out the value of 72 for nV just prior to the mex call, then that is what it is inside your mex function. So my guess is you are having a formatting issue with printing out the value inside your mex function. Check to make sure that the variable type of nV inside the mex function matches the print format. E.g., If nV is an int, use %d to print it out. If nV is a double, use %f to print it out. What is the code you are using to print out the value of nV inside the mex routine?
Related Question