/* mult_by_table.c  ../potential/tables  */


/******************************************/
/* 6 input & 1 output                     */
/* Big table    [0]                       */
/* Big domain   [1]                       */
/* big sizes    [2]                       */
/* Small table  [3]                       */
/* small domain [4]                       */
/* small sizes  [5]                       */
/*                                        */
/* New big table[0]                       */
/******************************************/

#include "mex.h"

void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[]){
  int     i, j, count, NB, NS, siz_b, siz_s, ndim, temp;
  int     *mask, *sx, *sy, *cpsy, *subs, *s, *cpsy2;
  double  *pbDomain, *psDomain, *sp, *zp, *bs;
  
  plhs[0] = mxDuplicateArray(prhs[0]);
  zp = mxGetPr(plhs[0]);
  
  siz_b = mxGetNumberOfElements(prhs[1]);
  siz_s = mxGetNumberOfElements(prhs[4]);
  pbDomain = mxGetPr(prhs[1]);
  psDomain = mxGetPr(prhs[4]);
  
  NB = mxGetNumberOfElements(prhs[0]);
  NS = mxGetNumberOfElements(prhs[3]);
  sp = mxGetPr(prhs[3]);
  
  bs = mxGetPr(prhs[2]);
  
  if(NS == 1){
    for(i=0; i<NB; i++){
      zp[i] *= *sp;
    }
    return;
  }
  
  if(NS == NB){
    for(i=0; i<NB; i++){
      zp[i] *= sp[i];
    }
    return;
  }
  
  mask = malloc(siz_s * sizeof(int));
  count = 0;
  for(i=0; i<siz_s; i++){
    for(j=0; j<siz_b; j++){
      if(psDomain[i] == pbDomain[j]){
	mask[count] = j;
	count++;
	break;
      }
    }
  }
  
  ndim = siz_b;
  sx = (int *)malloc(sizeof(int)*ndim);
  sy = (int *)malloc(sizeof(int)*ndim);
  for(i=0; i<ndim; i++){
    sx[i] = (int)bs[i];
    sy[i] = 1;
  }
  for(i=0; i<count; i++){
    temp = mask[i];
    sy[temp] = sx[temp];
  }
  
  s = (int *)malloc(sizeof(int)*ndim);
  *(cpsy = (int *)malloc(sizeof(int)*ndim)) = 1;
  subs =   (int *)malloc(sizeof(int)*ndim);
  cpsy2 =  (int *)malloc(sizeof(int)*ndim);
  for(i = 0; i < ndim; i++){
    subs[i] = 0;
    s[i] = sx[i] - 1;
  }
  
  for(i = 0; i < ndim-1; i++){
    cpsy[i+1] = cpsy[i]*sy[i]--;
    cpsy2[i] = cpsy[i]*sy[i];
  }
  cpsy2[ndim-1] = cpsy[ndim-1]*(--sy[ndim-1]);
  
  for(j=0; j<NB; j++){
    *zp++ *= *sp;
    for(i = 0; i < ndim; i++){
      if(subs[i] == s[i]){
	subs[i] = 0;
	if(sy[i])
	  sp -= cpsy2[i];
      }
      else{
	subs[i]++;
	if(sy[i])
	  sp += cpsy[i];
	break;
      }
    }
  }
  free(sx);
  free(sy);
  free(s);
  free(cpsy);
  free(subs);
  free(cpsy2);
  free(mask);
}

