igl/matlabinterface.h

//
//  IGL Lib - Simple C++ mesh library 
//
//  Copyright 2011, Daniele Panozzo. All rights reserved.

// WARNING: These functions require matlab installed
// Additional header folder required:
//   /Applications/MATLAB_R2010b.app/extern/include
// Additional binary lib to be linked with:
// /Applications/MATLAB_R2010b.app/bin/maci64/libeng.dylib
// /Applications/MATLAB_R2010b.app/bin/maci64/libmx.dylib

// MAC ONLY:
// Add to the environment variables:
// DYLD_LIBRARY_PATH = /Applications/MATLAB_R2010b.app/bin/maci64
// PATH = /opt/local/bin:/opt/local/sbin:/Applications/MATLAB_R2010b.app/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/texbin:/usr/X11/bin

#ifndef MATLAB_INTERFACE_H
#define MATLAB_INTERFACE_H

#include <Eigen/Core>
#include <string>

#include <complex>
#include <cassert>
#include <map>
#include <string>
#include <vector>

#include "engine.h"  // Matlab engine header

namespace igl 
{
    // Global pointer to the matlab engine
    Engine* mlengine = 0;

    // Init the MATLAB engine 
    // (no need to call it directly since it is automatically invoked by any other command)
    void mlinit()
    {
        mlengine = engOpen("\0");
    }
    
    // Closes the MATLAB engine
    void mlclose(Engine* engine)
    {
        engClose(mlengine);
        mlengine = 0;
    }

    // Send a matrix to MATLAB
    void mlsetmatrix(std::string name, Eigen::MatrixXd& M)
    {
        if (mlengine == 0)
            mlinit();
        
        mxArray *A = mxCreateDoubleMatrix(M.rows(), M.cols(), mxREAL);
        double *pM = mxGetPr(A);
        
        int c = 0;
        for(int j=0; j<M.cols();++j)
            for(int i=0; i<M.rows();++i)
                pM[c++] = double(M(i,j));
        
        engPutVariable(mlengine, name.c_str(), A);
        mxDestroyArray(A);
    }
    
    // Send a matrix to MATLAB
    void mlsetmatrix(std::string name, Eigen::MatrixXi& M)
    {
        if (mlengine == 0)
            mlinit();
        
        mxArray *A = mxCreateDoubleMatrix(M.rows(), M.cols(), mxREAL);
        double *pM = mxGetPr(A);
        
        int c = 0;
        for(int j=0; j<M.cols();++j)
            for(int i=0; i<M.rows();++i)
                pM[c++] = double(M(i,j))+1;
        
        engPutVariable(mlengine, name.c_str(), A);
        mxDestroyArray(A);
    }
    
    // Receive a matrix from MATLAB
    void mlgetmatrix(std::string name, Eigen::MatrixXd& M)
    {
        if (mlengine == 0)
            mlinit();

        unsigned long m = 0;
        unsigned long n = 0;
        std::vector<double> t;
        
        mxArray *ary = engGetVariable(mlengine, name.c_str());
        if (ary == NULL)
        {
            m = 0;
            n = 0;
            M = Eigen::MatrixXd(0,0);
        }
        else
        {
            m = mxGetM(ary);
            n = mxGetN(ary);
            M = Eigen::MatrixXd(m,n);
            
            double *pM = mxGetPr(ary);
            
            int c = 0;
            for(int j=0; j<M.cols();++j)
                for(int i=0; i<M.rows();++i)
                    M(i,j) = pM[c++];
        }
        
        mxDestroyArray(ary);
    }

    // Receive a matrix from MATLAB
    void mlgetmatrix(std::string name, Eigen::MatrixXi& M)
    {
        if (mlengine == 0)
            mlinit();

        unsigned long m = 0;
        unsigned long n = 0;
        std::vector<double> t;
        
        mxArray *ary = engGetVariable(mlengine, name.c_str());
        if (ary == NULL)
        {
            m = 0;
            n = 0;
            M = Eigen::MatrixXi(0,0);
        }
        else
        {
            m = mxGetM(ary);
            n = mxGetN(ary);
            M = Eigen::MatrixXi(m,n);
            
            double *pM = mxGetPr(ary);
            
            int c = 0;
            for(int j=0; j<M.cols();++j)
                for(int i=0; i<M.rows();++i)
                    M(i,j) = int(pM[c++])-1;
        }
        
        mxDestroyArray(ary);
    }

    // Send a single scalar to MATLAB
    void mlsetscalar(std::string name, double s)
    {
        if (mlengine == 0)
            mlinit();

        Eigen::MatrixXd M(1,1);
        M(0,0) = s;
        mlsetmatrix(name, M);
    }
    
    // Receive a single scalar from MATLAB
    double mlgetscalar(std::string name)
    {
        if (mlengine == 0)
            mlinit();

        Eigen::MatrixXd M;
        mlgetmatrix(name,M);
        return M(0,0);
    }

    // Execute arbitrary MATLAB code and return the MATLAB output
    std::string mleval(std::string code)
    {
        if (mlengine == 0)
            mlinit();

        const char *matlab_code = code.c_str();
        const int BUF_SIZE = 4096*4096;
        // allocate on the heap to avoid running out of stack
        std::string bufauto(BUF_SIZE+1, '\0');
        char *buf = &bufauto[0];
        
        assert(matlab_code != NULL);
        
        // Use RAII ensure that on leaving this scope, the output buffer is
        // always nullified (to prevent Matlab from accessing memory that might
        // have already been deallocated).
        struct cleanup {
            Engine *m_ep;
            cleanup(Engine *ep) : m_ep(ep) { }
            ~cleanup() { engOutputBuffer(m_ep, NULL, 0); }
        } cleanup_obj(mlengine);
        
        if (buf != NULL)
            engOutputBuffer(mlengine, buf, BUF_SIZE);
        
        int res = engEvalString(mlengine, matlab_code);
        
        if (res != 0) {
            std::ostringstream oss;
            oss << "ERROR: Matlab command failed with error code " << res << ".\n";
            return oss.str();
        }
        
        if (buf[0] == '>' && buf[1] == '>' && buf[2] == ' ')
            buf += 3;
        if (buf[0] == '\n') ++buf;
        
        return std::string(buf);
    }

}

#endif