src/matlab/dai_potstrength.cpp

   1 /*  This file is part of libDAI - http://www.libdai.org/
   2  *
   3  *  libDAI is licensed under the terms of the GNU General Public License version
   4  *  2, or (at your option) any later version. libDAI is distributed without any
   5  *  warranty. See the file COPYING for more details.
   6  *
   7  *  Copyright (C) 2006-2009  Joris Mooij  [joris dot mooij at libdai dot org]
   8  *  Copyright (C) 2006-2007  Radboud University Nijmegen, The Netherlands
   9  */
  10
  11
  12 #include <iostream>
  13 #include "mex.h"
  14 #include <dai/matlab/matlab.h>
  15 #include <dai/factor.h>
  16
  17
  18 using namespace std;
  19 using namespace dai;
  20
  21
  22 /* Input Arguments */
  23
  24 #define PSI_IN          prhs[0]
  25 #define I_IN            prhs[1]
  26 #define J_IN            prhs[2]
  27 #define NR_IN           3
  28
  29
  30 /* Output Arguments */
  31
  32 #define N_OUT           plhs[0]
  33 #define NR_OUT          1
  34
  35
  36 void mexFunction( int nlhs, mxArray *plhs[], int nrhs, const mxArray*prhs[] ) {
  37     long ilabel, jlabel;
  38
  39     // Check for proper number of arguments
  40     if ((nrhs != NR_IN) || (nlhs != NR_OUT)) {
  41         mexErrMsgTxt("Usage: N = dai_potstrength(psi,i,j);\n\n"
  42         "\n"
  43         "INPUT:  psi        = structure with a Member field and a P field, like a CPTAB.\n"
  44         "        i          = label of a variable in psi.\n"
  45         "        j          = label of another variable in psi.\n"
  46         "\n"
  47         "OUTPUT: N          = strength of psi in direction i->j.\n");
  48     }
  49
  50     // Get input parameters
  51     Factor psi = mx2Factor(PSI_IN);
  52     ilabel = (long)*mxGetPr(I_IN);
  53     jlabel = (long)*mxGetPr(J_IN);
  54
  55     // Find variable in psi with label ilabel
  56     Var i;
  57     for( VarSet::const_iterator n = psi.vars().begin(); n != psi.vars().end(); n++ )
  58         if( n->label() == ilabel ) {
  59             i = *n;
  60             break;
  61         }
  62     DAI_ASSERT( i.label() == ilabel );
  63
  64     // Find variable in psi with label jlabel
  65     Var j;
  66     for( VarSet::const_iterator n = psi.vars().begin(); n != psi.vars().end(); n++ )
  67         if( n->label() == jlabel ) {
  68             j = *n;
  69             break;
  70         }
  71     DAI_ASSERT( j.label() == jlabel );
  72
  73     // Calculate N(psi,i,j);
  74     double N = psi.strength( i, j );
  75
  76     // Hand over result to MATLAB
  77     N_OUT = mxCreateDoubleMatrix(1,1,mxREAL);
  78     *(mxGetPr(N_OUT)) = N;
  79
  80     return;
  81 }