一、代码matrixMultiply.c 从自带例子中拷贝过来：
>> copyfile(fullfile(matlabroot,'extern','examples','refbook','matrixMultiply.c'),'.')>> ls mat*
>> ls mat*
matlab.mat matrixMultiply.c mattest.mat
>> fileattrib('matrixMultiply.c','+w')cat matrixMultiply.c
/*=========================================================
* matrixMultiply.c - Example for illustrating how to use
* BLAS within a C MEX-file. matrixMultiply calls the
* BLAS function dgemm.
*
* C = matrixMultiply(A,B) computes the product of A*B,
* where A, B, and C are matrices.
*
* This is a MEX-file for MATLAB.
* Copyright 2009-2010 The MathWorks, Inc.
*=======================================================*/
#if !defined(_WIN32)
#define dgemm dgemm_
#endif
#include "mex.h"
#include "blas.h"
void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
double *A, *B, *C; /* pointers to input & output matrices*/
size_t m,n,p; /* matrix dimensions */
/* form of op(A) & op(B) to use in matrix multiplication */
char *chn = "N";
/* scalar values to use in dgemm */
double one = 1.0, zero = 0.0;
A = mxGetPr(prhs[0]); /* first input matrix */
B = mxGetPr(prhs[1]); /* second input matrix */
/* dimensions of input matrices */
m = mxGetM(prhs[0]);
p = mxGetN(prhs[0]);
n = mxGetN(prhs[1]);
if (p != mxGetM(prhs[1])) {
mexErrMsgIdAndTxt("MATLAB:matrixMultiply:matchdims",
"Inner dimensions of matrix multiply do not match.");
}
/* create output matrix C */
plhs[0] = mxCreateDoubleMatrix(m, n, mxREAL);
C = mxGetPr(plhs[0]);
/* Pass arguments to Fortran by reference */
dgemm(chn, chn, &m, &n, &p, &one, A, &m, B, &p, &zero, C, &m);
}
二、编译：
>> mex -v matrixMultiply.c -lmwblas
详细模式已开。
... 正在查找编译器 'gcc-4.9'...
... 正在执行命令 'which gcc-4.9'...是('/usr/bin/gcc-4.9')。
... 正在执行命令 'gcc-4.9 -print-file-name=libstdc++.so'...是('/usr/lib/gcc/x86_64-linux-gnu/4.9/libstdc++.so')。
找到已安装的编译器 'gcc-4.9'。
Options file details
-------------------------------------------------------------------
Compiler location: /usr/bin/gcc-4.9
Options file: /home/mymotif/.matlab/R2017a/mex_C_glnxa64.xml
CMDLINE2 : /usr/bin/gcc-4.9 -pthread -Wl,--no-undefined -Wl,-rpath-link,/opt/local/MATLAB/R2017a/bin/glnxa64 -shared -O -Wl,--version-script,"/opt/local/MATLAB/R2017a/extern/lib/glnxa64/c_exportsmexfileversion.map" /tmp/mex_7030238084799_6443/matrixMultiply.o /tmp/mex_7030238084799_6443/c_mexapi_version.o -lmwblas -L"/opt/local/MATLAB/R2017a/bin/glnxa64" -lmx -lmex -lmat -lm -lstdc++ -o matrixMultiply.mexa64
CC : /usr/bin/gcc-4.9
DEFINES : -DTARGET_API_VERSION=700 -DUSE_MEX_CMD -D_GNU_SOURCE -DMATLAB_MEX_FILE
MATLABMEX : -DMATLAB_MEX_FILE
CFLAGS : -fexceptions -fPIC -fno-omit-frame-pointer -pthread
INCLUDE : -I"/opt/local/MATLAB/R2017a/extern/include" -I"/opt/local/MATLAB/R2017a/simulink/include"
COPTIMFLAGS : -O -DNDEBUG
CDEBUGFLAGS : -g
LD : /usr/bin/gcc-4.9
LDFLAGS : -pthread -Wl,--no-undefined -Wl,-rpath-link,/opt/local/MATLAB/R2017a/bin/glnxa64
LDTYPE : -shared
FUNCTIONMAP : "/opt/local/MATLAB/R2017a/extern/lib/glnxa64/mexFunction.map"
VERSIONMAP : "/opt/local/MATLAB/R2017a/extern/lib/glnxa64/c_exportsmexfileversion.map"
LINKEXPORT : -Wl,--version-script,"/opt/local/MATLAB/R2017a/extern/lib/glnxa64/mexFunction.map"
LINKEXPORTVER : -Wl,--version-script,"/opt/local/MATLAB/R2017a/extern/lib/glnxa64/c_exportsmexfileversion.map"
LINKLIBS : -lmwblas -L"/opt/local/MATLAB/R2017a/bin/glnxa64" -lmx -lmex -lmat -lm -lstdc++
LDOPTIMFLAGS : -O
LDDEBUGFLAGS : -g
MWCPPLIB : "/opt/local/MATLAB/R2017a/sys/os/glnxa64/libstdc++.so.6"
OBJEXT : .o
LDEXT : .mexa64
SETENV : CC="/usr/bin/gcc-4.9"
CXX="g++"
CFLAGS="-fexceptions -fPIC -fno-omit-frame-pointer -pthread -DTARGET_API_VERSION=700 -DUSE_MEX_CMD -D_GNU_SOURCE -DMATLAB_MEX_FILE "
CXXFLAGS="-fexceptions -fPIC -fno-omit-frame-pointer -pthread -std=c++11 -DTARGET_API_VERSION=700 -DUSE_MEX_CMD -D_GNU_SOURCE -DMATLAB_MEX_FILE "
COPTIMFLAGS="-O -DNDEBUG"
CXXOPTIMFLAGS="-O -DNDEBUG"
CDEBUGFLAGS="-g"
CXXDEBUGFLAGS="-g"
LD="/usr/bin/gcc-4.9"
LDXX="g++"
LDFLAGS="-pthread -Wl,--no-undefined -Wl,-rpath-link,/opt/local/MATLAB/R2017a/bin/glnxa64 -shared -lmwblas -L"/opt/local/MATLAB/R2017a/bin/glnxa64" -lmx -lmex -lmat -lm -lstdc++ -Wl,--version-script,"/opt/local/MATLAB/R2017a/extern/lib/glnxa64/mexFunction.map""
LDDEBUGFLAGS="-g"
GCC : /usr/bin/gcc-4.9
CPPLIBS : /usr/lib/gcc/x86_64-linux-gnu/4.9/libstdc++.so
MATLABROOT : /opt/local/MATLAB/R2017a
ARCH : glnxa64
SRC : /home/mymotif/matlab_workplace/matrixMultiply.c;/opt/local/MATLAB/R2017a/extern/version/c_mexapi_version.c
OBJ : /tmp/mex_7030238084799_6443/matrixMultiply.o;/tmp/mex_7030238084799_6443/c_mexapi_version.o
OBJS : /tmp/mex_7030238084799_6443/matrixMultiply.o /tmp/mex_7030238084799_6443/c_mexapi_version.o
SRCROOT : /home/mymotif/matlab_workplace/matrixMultiply
DEF : /tmp/mex_7030238084799_6443/matrixMultiply.def
EXP : matrixMultiply.exp
LIB : matrixMultiply.lib
EXE : matrixMultiply.mexa64
ILK : matrixMultiply.ilk
MANIFEST : matrixMultiply.mexa64.manifest
TEMPNAME : matrixMultiply
EXEDIR :
EXENAME : matrixMultiply
OPTIM : -O -DNDEBUG
LINKOPTIM : -O
CMDLINE1_0 : /usr/bin/gcc-4.9 -c -DTARGET_API_VERSION=700 -DUSE_MEX_CMD -D_GNU_SOURCE -DMATLAB_MEX_FILE -I"/opt/local/MATLAB/R2017a/extern/include" -I"/opt/local/MATLAB/R2017a/simulink/include" -fexceptions -fPIC -fno-omit-frame-pointer -pthread -O -DNDEBUG /home/mymotif/matlab_workplace/matrixMultiply.c -o /tmp/mex_7030238084799_6443/matrixMultiply.o
CMDLINE1_1 : /usr/bin/gcc-4.9 -c -DTARGET_API_VERSION=700 -DUSE_MEX_CMD -D_GNU_SOURCE -DMATLAB_MEX_FILE -I"/opt/local/MATLAB/R2017a/extern/include" -I"/opt/local/MATLAB/R2017a/simulink/include" -fexceptions -fPIC -fno-omit-frame-pointer -pthread -O -DNDEBUG /opt/local/MATLAB/R2017a/extern/version/c_mexapi_version.c -o /tmp/mex_7030238084799_6443/c_mexapi_version.o
-------------------------------------------------------------------
使用 'gcc-4.9' 编译。
/usr/bin/gcc-4.9 -c -DTARGET_API_VERSION=700 -DUSE_MEX_CMD -D_GNU_SOURCE -DMATLAB_MEX_FILE -I"/opt/local/MATLAB/R2017a/extern/include" -I"/opt/local/MATLAB/R2017a/simulink/include" -fexceptions -fPIC -fno-omit-frame-pointer -pthread -O -DNDEBUG /home/mymotif/matlab_workplace/matrixMultiply.c -o /tmp/mex_7030238084799_6443/matrixMultiply.o
In file included from /home/mymotif/matlab_workplace/matrixMultiply.c:18:0:
/opt/local/MATLAB/R2017a/extern/include/blas.h:585:0: warning: "dgemm" redefined
#define dgemm FORTRAN_WRAPPER(dgemm)
^
/home/mymotif/matlab_workplace/matrixMultiply.c:14:0: note: this is the location of the previous definition
#define dgemm dgemm_
^
/usr/bin/gcc-4.9 -c -DTARGET_API_VERSION=700 -DUSE_MEX_CMD -D_GNU_SOURCE -DMATLAB_MEX_FILE -I"/opt/local/MATLAB/R2017a/extern/include" -I"/opt/local/MATLAB/R2017a/simulink/include" -fexceptions -fPIC -fno-omit-frame-pointer -pthread -O -DNDEBUG /opt/local/MATLAB/R2017a/extern/version/c_mexapi_version.c -o /tmp/mex_7030238084799_6443/c_mexapi_version.o
/usr/bin/gcc-4.9 -pthread -Wl,--no-undefined -Wl,-rpath-link,/opt/local/MATLAB/R2017a/bin/glnxa64 -shared -O -Wl,--version-script,"/opt/local/MATLAB/R2017a/extern/lib/glnxa64/c_exportsmexfileversion.map" /tmp/mex_7030238084799_6443/matrixMultiply.o /tmp/mex_7030238084799_6443/c_mexapi_version.o -lmwblas -L"/opt/local/MATLAB/R2017a/bin/glnxa64" -lmx -lmex -lmat -lm -lstdc++ -o matrixMultiply.mexa64
MEX 已成功完成。三、运行：
>> A = [1 3 5; 2 4 7];
>> B = [-5 8 11; 3 9 21; 4 0 8];
>> X = matrixMultiply(A,B)
X =
24 35 114
30 52 162