问题
I try to write use magma library in matlab, so basically I write a mexfunction which incorporate c code using magma function and then compile this mexfunction into mexa64 file, thus I could use in matlab.
The mexfunction or source c code is below:(called eig_magma)
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <cuda_runtime_api.h>
#include <cublas.h>
// includes, project
#include "flops.h"
#include "magma.h"
#include "magma_lapack.h"
#include "testings.h"
#include <math.h>
#include "mex.h"
#define A(i,j) A[i + j*lda]
extern "C"
void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
#define L_OUT plhs[0]
#define A_IN prhs[0]
#define S_OUT plhs[1]
magma_init();
real_Double_t gpu_perf, gpu_time;
double *h_A, *h_R, *h_work, *L,*S;
double *w;
magma_int_t *iwork;
magma_int_t N, n2, info, lwork, liwork, lda, aux_iwork[1];
double aux_work[1];
magma_vec_t jobz = MagmaVec;
magma_uplo_t uplo = MagmaLower;
magma_int_t i,j;
N = mxGetM(A_IN);
lda = N;
n2 = lda*N;
// query for workspace sizes
magma_dsyevd( jobz, uplo,
N, NULL, lda, NULL,
aux_work, -1,
aux_iwork, -1,
&info );
lwork = (magma_int_t) aux_work[0];
liwork = aux_iwork[0];
TESTING_MALLOC_CPU( h_A, double, n2);
h_A = (double *)mxGetData(A_IN);
L_OUT = mxCreateDoubleMatrix(N,N,mxREAL);
L = mxGetPr(L_OUT);
S_OUT = mxCreateDoubleMatrix(N,1,mxREAL);
S = mxGetPr(S_OUT);
//print and check
printf("print out h_A\n");
for(i=0;i<N;i++)
{
for(j=0;j<N;j++)
printf("%f\t",h_A[i+j*lda]);
printf("\n");
}
/* Allocate host memory for the matrix */
TESTING_MALLOC_CPU( w, double, N );
TESTING_MALLOC_CPU( iwork, magma_int_t, liwork );
TESTING_MALLOC_PIN( h_R, double, N*lda );
TESTING_MALLOC_PIN( h_work, double, lwork );
printf("allocate memory on cpu with pin!\n");
printf("copy h_A to h_R, and then print h_R\n");
memcpy( h_R, h_A, sizeof(double)*n2);
// lapackf77_dlacpy( MagmaUpperLowerStr, &N, &N, h_A, &lda,h_R, &lda );
// print and check
for(i=0;i<N;i++)
{
for(j=0;j<N;j++)
{
printf("%f\t",h_R[i+j*lda]);
}
printf("\n");
}
/* Performs operation using MAGA */
gpu_time = magma_wtime();
printf("start eig\n");
magma_dsyevd( jobz, uplo,
N, h_R, lda, w,
h_work, lwork,
iwork, liwork,
&info );
gpu_time = magma_wtime() - gpu_time;
printf("%d\n",info);
if (info != 0)
printf("magma_dsyevd returned error %d: %s.\n",
(int) info, magma_strerror( info ));
printf("convey the output\n");
memcpy(L,h_R,sizeof(double)*n2);
memcpy(S,w,sizeof(double)*N);
TESTING_FREE_CPU( w );
TESTING_FREE_CPU( iwork );
TESTING_FREE_PIN( h_R );
TESTING_FREE_PIN( h_work);
TESTING_FINALIZE();
}
Because using magma need cuda and magma lib I write the makefile to compile the code into mex file:
# Paths where MAGMA, CUDA, and OpenBLAS are installed
MAGMADIR = /home/yuxin/magma-1.5.0
CUDADIR = /usr/local/cuda
MATLABHOME = /opt/share/MATLAB/R2012b.app/
CC = icpc
LD = icpc
CFLAGS = -Wall
LDFLAGS = -Wall -mkl=parallel
MEX_CFLAGS = -fPIC -ansi -pthread -DMX_COMPAT_32 \
-DMATLAB_MEX_FILE
MAGMA_CFLAGS := -DADD_ -DHAVE_CUBLAS -I$(MAGMADIR)/include -I$(CUDADIR)/include -I$(MAGMADIR)/testing
MAGMA_LIBS := -L$(MAGMADIR)/lib -L$(CUDADIR)/lib64 \
-lmagma -lcublas -lcudart
MEXLIBS := -L/opt/share/MATLAB/R2012b.app/bin/glnxa64 -lmx -lmex -lmat -lm -lstdc++
MEX_INCLU := -I$(MATLABHOME)/extern/include -I$(MATLABHOME)/simulink/include
MEXFLAGS := -shared
OBJECT = eig_magma.o
EXECUTABLE = eig_magma
$(EXECUTABLE): $(OBJECT)
$(CC) $(LDFLAGS) $(MEXFLAGS) $(OBJECT) -o $@ $(MAGMA_LIBS) $(MEXLIBS)
eig_magma.o: eig_magma.c
$(CC) $(CFLAGS) $(MAGMA_CFLAGS) $(MEX_INCLU) $(MEX_CFLAGS) -c $< -o $@
clean:
rm -rf eig_magma *.o eig_magma.mexa64
It could be compiled successfully, however when I run the eig_magma in matlab, and when matlab execute to
magma_dsyevd( jobz, uplo, N, h_R, lda, w, h_work, lwork, iwork, liwork, &info );
matlab crashed.......I also have tried to only write the eig_magma in c, without using mex function, it was compiled successfully and works fine.
Anyone has idea how to solve this problem?
Thank you
yuxin
回答1:
Let me give an example. Since I never worked with MAGMA before, I'm showing the same code only using regular LAPACK (code adapted from a previous answer I gave). It shouldn't be difficult to convert it to using MAGMA equivalent functions instead.
Note that MATLAB already ships with the BLAS/LAPACK libraries and the necessary header files for you to use from MEX-files. In fact this is the Intel MKL library, so it's a well-optimized implementation.
eig_lapack.cpp
#include "mex.h"
#include "lapack.h"
/*
// the following prototype is defined in "lapack.h" header
extern void dsyevd(char *jobz, char *uplo,
ptrdiff_t *n, double *a, ptrdiff_t *lda, double *w,
double *work, ptrdiff_t *lwork, ptrdiff_t *iwork, ptrdiff_t *liwork,
ptrdiff_t *info);
*/
void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
// validate input
if (nrhs != 1 || nlhs > 2)
mexErrMsgIdAndTxt("mex:error", "Wrong number of arguments.");
if (!mxIsDouble(prhs[0]) || mxIsComplex(prhs[0]))
mexErrMsgIdAndTxt("mex:error", "Input is not real double matrix.");
mwSignedIndex m = mxGetM(prhs[0]), n = mxGetN(prhs[0]);
if (m != n)
mexErrMsgIdAndTxt("mex:error", "Input is not square symmetric matrix.");
// allocate output
plhs[0] = mxDuplicateArray(prhs[0]);
plhs[1] = mxCreateDoubleMatrix(1, n, mxREAL);
double *A = mxGetPr(plhs[0]);
double *w = mxGetPr(plhs[1]);
// query and allocate the optimal workspace size
double workopt = 0;
mwSignedIndex iworkopt = 0;
mwSignedIndex lwork = -1, liwork = -1, info = 0;
dsyevd("Vectors", "Upper", &n, A, &n, w,
&workopt, &lwork, &iworkopt, &liwork, &info);
lwork = (mwSignedIndex) workopt;
liwork = (mwSignedIndex) iworkopt;
double *work = (double*) mxMalloc(lwork * sizeof(double));
mwSignedIndex *iwork = (mwSignedIndex*) mxMalloc(liwork * sizeof(mwSignedIndex));
// compute eigenvectors/eigenvalues
dsyevd("Vectors", "Upper", &n, A, &n, w,
work, &lwork, iwork, &liwork, &info);
mxFree(work);
mxFree(iwork);
// check successful computation
if (info < 0)
mexErrMsgIdAndTxt("mex:error", "Illegal values in arguments.");
else if (info > 0)
mexWarnMsgIdAndTxt("mex:warn", "Algorithm failed to converge.");
}
First we compile the MEX-file (I'm using VS2013 compiler on Windows):
>> mex -largeArrayDims eig_lapack.cpp libmwlapack.lib
Now I compare against the built-in eig function:
>> A = [1 2 3 4 5; 2 2 3 4 5; 3 3 3 4 5; 4 4 4 4 5; 5 5 5 5 5]
A =
1 2 3 4 5
2 2 3 4 5
3 3 3 4 5
4 4 4 4 5
5 5 5 5 5
>> [V,D] = eig(A)
V =
0.6420 -0.5234 0.3778 -0.1982 0.3631
0.4404 0.1746 -0.6017 0.5176 0.3816
0.1006 0.6398 -0.0213 -0.6356 0.4196
-0.2708 0.2518 0.6143 0.5063 0.4791
-0.5572 -0.4720 -0.3427 -0.1801 0.5629
D =
-3.1851 0 0 0 0
0 -0.7499 0 0 0
0 0 -0.3857 0 0
0 0 0 -0.2769 0
0 0 0 0 19.5976
>> [VV,DD] = eig_lapack(A)
VV =
0.6420 -0.5234 0.3778 -0.1982 0.3631
0.4404 0.1746 -0.6017 0.5176 0.3816
0.1006 0.6398 -0.0213 -0.6356 0.4196
-0.2708 0.2518 0.6143 0.5063 0.4791
-0.5572 -0.4720 -0.3427 -0.1801 0.5629
DD =
-3.1851 -0.7499 -0.3857 -0.2769 19.5976
the results are the same (though not guaranteed, seeing that eigenvectors are defined up-to a scale):
>> V-VV, D-diag(DD)
ans =
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
ans =
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
来源：https://stackoverflow.com/questions/26460513/using-magma-dysevd-in-mex-file-matlab