/*
	LPAD and CP-Logic interpreter
	
Copyright (c) 2007, Fabrizio Riguzzi

For the use of cudd:
Copyright (c) 1995-2004, Regents of the University of Colorado

All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:

Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.

Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.

Neither the name of the University of Colorado nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.

	This file contains the definition of Prob and ProbBool plus the functions
	for building the BDD
*/


#include "cplint.h"
#include <stdlib.h>




DdNode * retFunction(DdManager * mgr,array_t *expression, array_t *v)
/* given an expression term1+term2+...+termn, returns the BDD that implements that function */  
{
  array_t * term;
  DdNode * tNode, * tmp, *tmp1;
  int i;
  
  i=0;
  tNode=Cudd_ReadLogicZero(mgr);
  Cudd_Ref(tNode);
  while(i<array_n(expression))
  {
    term=array_fetch(array_t * ,expression,i);
    tmp=retTerm(mgr,term,v);
    Cudd_Ref(tmp);
    tmp1=Cudd_bddOr(mgr,tNode,tmp);
    Cudd_Ref(tmp1);
    Cudd_RecursiveDeref(mgr,tNode);
    tNode=tmp1;
    i++;    
  } 
  return tNode;
}

DdNode * retTerm(DdManager * mgr,array_t *term, array_t * v)
/* given a term V1=v1 and V2=v2 ... Vn=vn, returns the BDD that implements that function */  
{
  factor f;
  DdNode * fNode, * tmp, *tmp1;
  int i;
  
  i=0;
  fNode=Cudd_ReadOne(mgr);
  Cudd_Ref(fNode);
  while (i<array_n(term))
  {
    f=array_fetch(factor, term, i);
    tmp=retFactor(mgr,f,v);
    Cudd_Ref(tmp);
    tmp1= Cudd_bddAnd(mgr,fNode,tmp);
    Cudd_Ref(tmp1);
    Cudd_RecursiveDeref(mgr,fNode);
    fNode=tmp1;
    i++;
  } 
  return fNode;
}

DdNode * retFactor(DdManager * mgr, factor f, array_t * vars)
/* given a factor V=v, returns the BDD that implements that function */  
{
  int varIndex;
  int value;
  int i;
  int bit;
  variable v;
  DdNode * node, *booleanVar, * tmp;
  array_t * booleanVars;
  
  
  varIndex=f.var;
  value=f.value;
  v=array_fetch(variable, vars, varIndex);
  booleanVars=v.booleanVars;
  i=v.nBit-1;
  node=Cudd_ReadOne(mgr);
  Cudd_Ref(node);
  /* booelan var with index 0 in v.booleanVars is the most significant */
  do {
    booleanVar=array_fetch(DdNode *,booleanVars,i);
    bit=value & 01;
    if (bit)
    {
      tmp=Cudd_bddAnd(mgr,node,booleanVar);
      Cudd_Ref(tmp);
    }
    else
      {
      tmp=Cudd_bddAnd(mgr,node,Cudd_Not(booleanVar));
      Cudd_Ref(tmp);
      }
    value=value>>1;
    i--;
    Cudd_RecursiveDeref(mgr,node);
    node=tmp;
  } while (i>=0);
  return node;

}



double Prob(DdNode *node, array_t * vars,array_t * bVar2mVar, GHashTable * nodes)
/* compute the probability of the expression rooted at node
nodes is used to store nodes for which the probability has alread been computed
so that it is not recomputed
 */
{
  DdNode *T,*F;
  int index,mVarIndex,nBit;
  variable v;
  double p,res;
  double value;
  double * value_p;
  DdNode **key;
  double *rp;

  index=node->index;
  if (Cudd_IsConstant(node))
  {
    value=node->type.value;
    return value;
  }
  else
{
	
	value_p=g_hash_table_lookup(nodes,&node);
	if (value_p!=NULL)
	{
		return *value_p;
	}
	else
  	{
    		mVarIndex=array_fetch(int,bVar2mVar,index);
    		v=array_fetch(variable,vars,mVarIndex);
    		nBit=v.nBit;
    		res=ProbBool(node,0,nBit,0,v,vars,bVar2mVar,nodes);
		key=(DdNode **)malloc(sizeof(DdNode *));
		*key=node;
		rp=(double *)malloc(sizeof(double));
		*rp=res;
		g_hash_table_insert(nodes, key, rp);
    		return res;
  	}
}
}

double ProbBool(DdNode *node, int bits, int nBit,int posBVar,variable v,
array_t * vars,array_t * bVar2mVar, GHashTable * nodes)
/* explores a group of binary variables making up the multivalued variable v */
{
  DdNode *T,*F;
  double p,res;
  array_t * probs;
  double value;
  
  probs=v.probabilities;
  if (nBit==0)
  {
    if (bits>=array_n(probs))
      return 0;
    else
    {
      p=array_fetch(double,probs,bits);
      res=p*Prob(node,vars,bVar2mVar,nodes);
      return res;
    }
  }
  else
  {
    if (correctPosition(node->index,v,node,posBVar))
    {
      T = node->type.kids.T;
      F = node->type.kids.E;
      bits=bits<<1;
      
      res=ProbBool(T,bits+1,nBit-1,posBVar+1,v,vars,bVar2mVar,nodes)+ 
        ProbBool(F,bits,nBit-1,posBVar+1,v,vars,bVar2mVar,nodes);
      return res;
    }
    else
    {
      
      bits=bits<<1;
      res=ProbBool(node,bits+1,nBit-1,posBVar+1,v,vars,bVar2mVar,nodes)+ 
        ProbBool(node,bits,nBit-1,posBVar+1,v,vars,bVar2mVar,nodes);
      return res;
    }
  }
}

int correctPosition(int index,variable v, DdNode * node,int posBVar)
/* returns 1 is the boolean variable with index posBVar is in the correct position 
currently explored by ProbBool */
{
  DdNode * bvar;
  
  bvar=array_fetch(DdNode *,v.booleanVars,posBVar);
  return bvar->index==index;
}