monomial.c

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#include "monomial.h"

#include "error.h"
#include "defines.h"

#include <math.h>

void InitMonomial(Tmonomial *f)
{
  f->empty=TRUE;
  InitVarSet(&(f->vars));
  f->ct=0.0;
}

void ResetMonomial(Tmonomial *f)
{
  f->empty=TRUE;
  ResetVarSet(&(f->vars));
  f->ct=0.0;
}

void FixVariableInMonomial(unsigned int nv,double v,Tmonomial *f)
{
  unsigned int pos,power;

  pos=GetPlaceinSet(nv,&(f->vars)); /*This returns NO_UINT for empty var sets*/

  if (pos!=NO_UINT)
    {
      power=GetVariablePowerN(pos,&(f->vars));
      RemoveVariableFromSet(nv,&(f->vars));
      f->ct*=pow(v,power);
      if (fabs(f->ct)<=ZERO)
        ResetMonomial(f); 
    }

  /*the indexes for variables with ID above 'nv' should be decreased by one*/
  ShiftVarIndexes(nv,&(f->vars)); /*has no effects for empty var sets*/
}

void ReplaceVariableInMonomial(unsigned int nv,double ct,unsigned int nvNew,Tmonomial *f)
{
  unsigned int pos,power;

  pos=GetPlaceinSet(nv,&(f->vars));

  if (pos!=NO_UINT)
    {
      power=GetVariablePowerN(pos,&(f->vars));
      RemoveVariableFromSet(nv,&(f->vars));
      AddVariable2Set(nvNew,power,&(f->vars));
      
      f->ct*=pow(ct,power);
      if (fabs(f->ct)<=ZERO)
        ResetMonomial(f);
    }

  /*the indexes for variables with ID above 'nv' should be decreased by one*/
  ShiftVarIndexes(nv,&(f->vars));
}

boolean EmptyMonomial(Tmonomial *f)
{
  return(f->empty);
}

boolean CtMonomial(Tmonomial *f)
{
  return((f->empty)||
         (VariableSetSize(&(f->vars))==0));
}

boolean QuadraticMonomial(Tmonomial *f)
{
  return((VariableSetSize(&(f->vars))==1)&&
         (GetVariablePowerN(0,&(f->vars))==2));
}

boolean BilinearMonomial(Tmonomial *f)
{
  return((VariableSetSize(&(f->vars))==2)&&
         (GetVariablePowerN(0,&(f->vars))==1)&&
         (GetVariablePowerN(1,&(f->vars))==1));
}

boolean LinearMonomial(Tmonomial *f)
{
  return((VariableSetSize(&(f->vars))==1)&&
         (GetVariablePowerN(0,&(f->vars))==1));
}

unsigned int MonomialOrder(Tmonomial *f)
{
  return(VarSetOrder(&(f->vars)));
}

void CopyMonomial(Tmonomial *f_dst,Tmonomial *f_orig)
{
  f_dst->empty=f_orig->empty;
  f_dst->ct=f_orig->ct;
  CopyVarSet(&(f_dst->vars),&(f_orig->vars));
}

unsigned int CmpMonomial(Tmonomial *f1,Tmonomial *f2)
{
  unsigned int r;

  if ((f1->empty)&&(f2->empty))
    r=0;
  else
    {
      if (f1->empty)
        r=2;
      else
        {
          if (f2->empty)
            r=1;
          else
            {
              r=CmpVarSet(&(f1->vars),&(f2->vars));
              if (r==0)
                {
                  if (f1->ct>f2->ct)
                    r=1;
                  else
                    {
                      if (f1->ct<f2->ct)
                        r=2;
                    }
                }
            }
        }
    }
  return(r);
}

double GetMonomialCt(Tmonomial *f)
{
  if (f->empty)
    return(0);
  else
    return(f->ct);
}

void SetMonomialCt(double k,Tmonomial *f)
{
  f->empty=FALSE;
  f->ct=k;

  if (fabs(f->ct)<=ZERO)
    ResetMonomial(f);
}

Tvariable_set *GetMonomialVariables(Tmonomial *f)
{
  return(&(f->vars));
}

void AddCt2Monomial(double k,Tmonomial *f)
{
  if (f->empty)
    f->ct=k;
  else
    f->ct*=k;

  f->empty=FALSE;

  if (fabs(f->ct)<=ZERO)
    f->ct=0.0;
}

void AddVariable2Monomial(unsigned int varid,unsigned int p,Tmonomial *f)
{
  if (f->empty)
    {
      f->empty=FALSE;
      f->ct=1;
      AddVariable2Set(varid,p,&(f->vars));
    }
  else
    AddVariable2Set(varid,p,&(f->vars));
}

double EvaluateMonomial(double *varValues,Tmonomial *f)
{
  if (f->empty)
    return(0.0);
  else
    {
      if (VariableSetSize(&(f->vars))>0)
        return(f->ct*EvaluateVarSet(varValues,&(f->vars)));
      else
        return(f->ct);
    }
}

void EvaluateMonomialInt(Tinterval *varValues,Tinterval *i_out,Tmonomial *f)
{  
  if (f->empty)
    NewInterval(0,0,i_out);
  else
    {
      if (VariableSetSize(&(f->vars))>0)
        {
          Tinterval ct;

          EvaluateVarSetInt(varValues,i_out,&(f->vars));

          /* The coefficients of the equations can be affected by some noise
             due to floating point roundings when operating them. We add a small
             range (1e-11) to compensate for those possible errors. */
          NewInterval(f->ct-ZERO,f->ct+ZERO,&ct);
          IntervalProduct(&ct,i_out,i_out);
        }
      else
        {
          /* The coefficients of the equations can be affected by some noise
             due to floating point roundings when operating them. We add a small
             range (1e-11) to compensate for those possible errors. */
          NewInterval(f->ct-ZERO,f->ct+ZERO,i_out);
        }
    }
}

void DeriveMonomial(unsigned int nv,Tmonomial *df,Tmonomial *f)
{
  if ((f->empty)||(!VarIncluded(nv,&(f->vars))))
    InitMonomial(df);
  else
    {
      /* The output of 'DeriveVarSet' is >0 since we now for sure the
         var set includes variable 'nv;*/
      df->ct=f->ct*(double)DeriveVarSet(nv,&(df->vars),&(f->vars));
      df->empty=FALSE;
    }
}


void PrintMonomial(FILE *file,boolean first,char **varNames,Tmonomial *f)
{
  if (!f->empty)
    {
      if (first)
        {
          if (fabs(f->ct-1)>ZERO)
            {
              fprintf(file,"%.12g",f->ct);
              if (!EmptyVarSet(&(f->vars)))
                fprintf(file,"*");
            }
        }
      else
        {
          if (fabs(f->ct-1)<ZERO)
            fprintf(file,"+");
          else
            {
              if (fabs(f->ct+1)<ZERO)
                fprintf(file,"-");
              else
                {
                  fprintf(file,"%+.12g",f->ct);
                  if (!EmptyVarSet(&(f->vars)))
                    fprintf(file,"*");
                }
            }
        }

      PrintVarSet(file,varNames,&(f->vars));
    }
}

void DeleteMonomial(Tmonomial *f)
{
  DeleteVarSet(&(f->vars));
}