vl_irodr.c

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/* file:        irodr.mex.c
** author:      Andrea Vedaldi
** description: Inverse rodrigues formula
**/

/*
Copyright (C) 2007-12 Andrea Vedaldi and Brian Fulkerson.
All rights reserved.

This file is part of the VLFeat library and is made available under
the terms of the BSD license (see the COPYING file).
*/

#include <mexutils.h>

#include <vl/rodrigues.h>

enum {
  IN_R = 0
} ;

enum {
  OUT_OM=0,
  OUT_DOM
} ;

/* -------------------------------------------------------------------
**                                                              Driver
** ----------------------------------------------------------------- */

void
mexFunction(int nout, mxArray *out[],
            int nin, const mxArray *in[])
{
  int k,K ;
  double* om_pt ;
  double* dom_pt ;
  double const * R_pt ;

  /* -----------------------------------------------------------------
  **                                               Check the arguments
  ** -------------------------------------------------------------- */
  if(nin != 1) {
    mexErrMsgTxt("Exactly one argument required.") ;
  }

  if(!vlmxIsMatrix(in[IN_R],-1,-1)) {
    mexErrMsgTxt("R must be a DOUBLE array") ;
  }

  K = mxGetNumberOfElements(in[IN_R]) ;
  if(K % 9 || K < 9) {
    mexErrMsgTxt("The elements of R must be a multiple of 9.") ;
  }
  K /= 9 ;
  R_pt = mxGetPr(in[IN_R]) ;

  /* space for output (OM) */
  out[OUT_OM] = mxCreateDoubleMatrix(3,1,mxREAL) ;
  om_pt = mxGetPr(out[OUT_OM]) ;

  /* space for optional output (dR) */
  dom_pt = NULL ;
  if( nout > 1 ) {
    if( K == 1 ) {
      out[OUT_DOM] = mxCreateDoubleMatrix(3,9,mxREAL) ;
    } else {
      mwSize dims [3] ;
      dims[0] = 3 ; dims[1] = 9 ; dims[2] = K ;
      out[OUT_DOM] = mxCreateNumericArray(3,dims,mxDOUBLE_CLASS,mxREAL) ;
    }
    dom_pt = mxGetPr(out[OUT_DOM]) ;
  }

  /* -----------------------------------------------------------------
  **                                                           Process
  ** -------------------------------------------------------------- */
  for(k = 0 ; k < K ; ++k) {
    vl_irodrigues(om_pt, dom_pt, R_pt) ;
    om_pt  += 3 ;
    dom_pt += 3*9 ;
    R_pt   += 3*3 ;
  }

}