C与MATLAB混合编程(C语言中调用MATLAB)
一、用C/C++编写matlab函数(mexAdd.cpp)供后面测试用
#include "mex.h"
double add(double x, double y)
{
return x + y;
}
void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
double *a;
double b, c;
plhs[0] = mxCreateDoubleMatrix(1, 1, mxREAL);
a = mxGetPr(plhs[0]);
b = *(mxGetPr(prhs[0]));
c = *(mxGetPr(prhs[1]));
*a = add(b, c);
}
并在matlab中编译：mex mexAdd.cpp
二、安装csh，否则在不能启动matlab引擎即engOpen(NULL)始终返回0
sudo apt-get install tcsh
或
sudo apt-get install csh
三、创建一个目录qtmatlab在下面放源文件main.cpp
#include <QtGui/QApplication>
#include <QDebug>
#include <cmath>
#include <iostream>
#include <engine.h>
int main(int argc, char *argv[])
{
// Test 1：将C++中的数据送入Matlab执行
// [1] 启动Matlab引擎
Engine *ep = engOpen(NULL);
if (!ep)
{ // 定义Matlab引擎指针，启动引擎；失败则返回NULL
qDebug() << "Can't start Matlab engine!";
exit(-1);
}
engSetVisible(ep, false);
// [2] 在C++内存空间构造需要计算或者画图的数据
const int N_SIZE = 10;
double x[N_SIZE],y[N_SIZE];
for (int i=0; i<N_SIZE; i++) //计算数组x和y
{
x[i] = (i+1);
y[i] = sin(x[i]); //产生正弦值
}
// [3] 在C++内存空间定义Matlab数组
mxArray *xx = mxCreateDoubleMatrix(1,N_SIZE, mxREAL); // 定义mxArray，为行，N_SIZE 列的实数数组
mxArray *yy = mxCreateDoubleMatrix(1,N_SIZE, mxREAL);
// [4] 将数据拷贝到数组中
memcpy(mxGetPr(xx), x, N_SIZE*sizeof(double)); // 将数组x复制到mxarray数组xx中
memcpy(mxGetPr(yy), y, N_SIZE*sizeof(double));
// [5] 将C++内存空间的数据传输到Matlab引擎中
engPutVariable(ep, "xx",xx); // 将mxArray数组xx写入到Matlab工作空间，命名为xx
engPutVariable(ep, "yy",yy);
// [6] 执行Matlab引擎
engEvalString(ep, "plot(xx, yy); "); // 向Matlab引擎发送画图命令
// [7] 销毁C++内存空间的数据
mxDestroyArray(xx); // 销毁mxArray数组xx和yy
mxDestroyArray(yy);
// Test 2：显示Matlab控制台输出信息
// [1] 将Matlab的输出连接到buffer
const int BUFSIZE = 1024;
char buffer[BUFSIZE] = {'\0'};
engOutputBuffer(ep, buffer, BUFSIZE);
// [2] 显示Matlab里数据的值
engEvalString(ep, "xx");
qDebug() << buffer;
engEvalString(ep, "yy");
qDebug() << buffer;
// Test 3：从Matlab引擎传回数据
mxArray *_xx = engGetVariable(ep, "xx");
double *_x = mxGetPr(_xx);
mxArray *_yy = engGetVariable(ep, "yy");
double *_y = mxGetPr(_yy);
for (int i = 0; i < N_SIZE; i++)
{
qDebug() << "i=" << i << "|" << _x[i] << _y[i];
}
// 销毁mxArray数组_xx和_yy
mxDestroyArray(_xx);
mxDestroyArray(_yy);
//Test 4：执行自定义函数(刚才写的那个函数)
engEvalString(ep, "cd /home/mymotif/matlab_workplace; c = mexAdd(1,2)");
qDebug() << buffer;
engClose(ep); //关闭Matlab引擎
return 0;
}
四、编译运行
qmake -project
产生qtmatlab.pro
编辑qtmatlab.pro追加下面两行：
INCLUDEPATH += /opt/local/MATLAB/R2012a/extern/include
LIBS += -L"/opt/local/MATLAB/R2012a/bin/glnxa64" -leng -lmat -lmex -lmx -Wl,-rpath=/opt/local/MATLAB/R2012a/bin/glnxa64
其中的/opt/local/MATLAB/R2012a是MATLAB安装路径、需要根据实际环境修改
修改后的qtmatlab.pro内容如下：
###################################################################### # Automatically generated by qmake (2.01a) ?? 3? 16 19:58:53 2016 ###################################################################### TEMPLATE = app TARGET = DEPENDPATH += . INCLUDEPATH += . INCLUDEPATH += /opt/local/MATLAB/R2012a/extern/include LIBS += -L"/opt/local/MATLAB/R2012a/bin/glnxa64" -leng -lmat -lmex -lmx -Wl,-rpath=/opt/local/MATLAB/R2012a/bin/glnxa64 # Input SOURCES += main.cpp
qmake
make
./qtmatlab
五、testmat.c
//gcc-4.9 testmat.c -o testmat -I/opt/local/MATLAB/R2012a/extern/include -L/opt/local/MATLAB/R2012a/bin/glnxa64 -lm -leng -lmat -lmex -lmx
#include<stdio.h>
#include<math.h>
#include<stdlib.h>
#include<engine.h>
#include<string.h>
int main(int argc,char** argv)
{
Engine *ep;
if (!(ep = engOpen("\0"))) //启动matlab 引擎
{
fprintf(stderr, "\nCan't start MATLAB engine\n");
return EXIT_FAILURE;
}
engSetVisible(ep,false);
mxArray *H = NULL, *f = NULL, *A = NULL, *b = NULL, *lb = NULL,*x = NULL;
H = mxCreateDoubleMatrix(2, 2, mxREAL);
f = mxCreateDoubleMatrix(2, 1, mxREAL);
A = mxCreateDoubleMatrix(3, 2, mxREAL);
b = mxCreateDoubleMatrix(3, 1, mxREAL);
lb = mxCreateDoubleMatrix(2,1, mxREAL);
x = mxCreateDoubleMatrix(2,1, mxREAL);
double HH[2][2]={1,-1,-1,2};
double ff[2][1]={-2,-6};
double AA[3][2]={1,1,-1,2,2,1};
double bb[3][1]={2,2,3};
double llbb[2][1]={0,0};
double xx[2][1]={0,0};
//把C数组转换为Matlab数组
memcpy((void *)mxGetPr(H), (void *)HH, sizeof(double)*2*2);
memcpy((void *)mxGetPr(f), (void *)ff, sizeof(double)*2*1);
memcpy((void *)mxGetPr(A), (void *)AA, sizeof(double)*3*2);
memcpy((void *)mxGetPr(b), (void *)bb, sizeof(double)*3*1);
memcpy((void *)mxGetPr(lb), (void *)llbb,sizeof(double)*2*1);
memcpy((void *)mxGetPr(x), (void *)xx,sizeof(double)*2*1);
//把数组变量写入Matlab环境中
engPutVariable(ep, "H", H);
engPutVariable(ep, "f",f);
engPutVariable(ep,"A",A);
engPutVariable(ep,"b",b);
engPutVariable(ep,"lb",lb);
engPutVariable(ep,"x",x);
//执行字符串命令
int ret1 = engEvalString(ep,"H = [1 -1; -1 2];");
int ret2 = engEvalString(ep,"f = [-2; -6];");
int ret3 = engEvalString(ep,"A = [1 1; -1 2; 2 1];");
int ret4 = engEvalString(ep,"b = [2; 2; 3];");
int ret5 = engEvalString(ep,"lb = zeros(2,1);");
int ret6 = engEvalString(ep,"[x] = quadprog(H,f,A,b,[],[],lb,[],[]);");
char p[256]={0};
char p1[256]={0};
char* ans = "disp(x(1,1));";
char* ans2 = "disp(x(2,1));";
engOutputBuffer(ep,p,240);
engEvalString(ep,ans);
printf("p:%s\n",p);
engOutputBuffer(ep,p1,240);
engEvalString(ep,ans2);
printf("p1:%s,\n",p1);
mxDestroyArray(H);
mxDestroyArray(f);
mxDestroyArray(A);
mxDestroyArray(b);
mxDestroyArray(x);
engClose(ep);
return 0;
}
这里只能用gcc4.x编译，最新的gcc5.3会出错
~$ ./testmat
p:>> 0.6667
p1:>> 1.3333
,