fvar_fn.cpp

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/*
 * $Id$
 *
 * Author: David Fournier
 * Copyright (c) 2008-2012 Regents of the University of California
 */
#include "fvar.hpp"

#ifdef __TURBOC__
  #pragma hdrstop
  #include <iostream.h>
  #include <iomanip.h>
#endif

#ifdef __ZTC__
  #include <iostream.hpp>
  #include <iomanip.hpp>
#endif

#include <stdio.h>
#include <math.h>

prevariable& pow(const prevariable& v1, const double u)
{
#ifndef OPT_LIB
  if (v1.v->x == 0)
  {
    cerr << "Error -- base = 0 in function"
            " prevariable& pow(const prevariable& v1, const double u)" << endl;
  }
#endif
  dvariable* RETURN_PTR = gradient_structure::next_RETURN_PTR();

  double x=::pow(v1.v->x,u-1);
  double y=x* v1.v->x;

  RETURN_PTR->v->x=y;
  gradient_structure::GRAD_STACK1->set_gradient_stack(default_evaluation,
        &(RETURN_PTR->v->x), &(v1.v->x), u * x );

  return *RETURN_PTR;
}

 void prevariable::initialize(void)
 {
   *this = 0.0;
 }

prevariable& sin(const prevariable& v1)
{
  dvariable* RETURN_PTR = gradient_structure::next_RETURN_PTR();

  RETURN_PTR->v->x=::sin(v1.v->x);
  gradient_structure::GRAD_STACK1->set_gradient_stack(default_evaluation,
    &(RETURN_PTR->v->x), &(v1.v->x), ::cos(v1.v->x) );

  return *RETURN_PTR;
}

prevariable& sigmoid(const prevariable& v1)
{
  dvariable* RETURN_PTR = gradient_structure::next_RETURN_PTR();

  double tmp=v1.v->x;

  //gradient_structure::RETURN_PTR->v->x=atan(tmp)/1.5708;
  RETURN_PTR->v->x=::atan(tmp)/2.8;

  gradient_structure::GRAD_STACK1->set_gradient_stack(default_evaluation,
     &(RETURN_PTR->v->x), &(v1.v->x),
 //                1./((1.+tmp*tmp)*1.5708));
                   1./((1.+tmp*tmp)*2.8));
  return *RETURN_PTR;
}


prevariable& fabs(const prevariable& v1)
{
  dvariable* RETURN_PTR = gradient_structure::next_RETURN_PTR();

  double tmp=v1.v->x;
  RETURN_PTR->v->x=fabs(tmp);
  gradient_structure::GRAD_STACK1->set_gradient_stack(
    default_evaluation,&(RETURN_PTR->v->x),
    &(v1.v->x), tmp >= 0.0 ? 1.0 : -1.0);

  return *RETURN_PTR;
}

prevariable& sfabs(const prevariable& v1)
{
  #define cutoff 0.001 //  h
  #define cutoff2 0.000001
  double a = 2./cutoff; // 2.0/h
  double b = 1./cutoff2; // 1.0/(h*h)

  dvariable* RETURN_PTR = gradient_structure::next_RETURN_PTR();

  double tmp1=v1.v->x;
  double tmp=::fabs(tmp1);

  if (tmp > cutoff)
  {
    RETURN_PTR->v->x=tmp;
    if (tmp1 >=0)
    {
      gradient_structure::GRAD_STACK1->set_gradient_stack(
        default_evaluation,&(RETURN_PTR->v->x),
        &(v1.v->x),1);
    }
    else
    {
      gradient_structure::GRAD_STACK1->set_gradient_stack(
        default_evaluation,&(RETURN_PTR->v->x),
        &(v1.v->x),-1);
    }
  }
  else
  {
    double t2 = tmp * tmp;
    if (tmp1 >=0)
    {
      RETURN_PTR->v->x=t2*(a-b*tmp1);
      gradient_structure::GRAD_STACK1->set_gradient_stack(
        default_evaluation,&(RETURN_PTR->v->x),
        &(v1.v->x),tmp*(2*a-3*b*tmp1) );
    }
    else
    {
      RETURN_PTR->v->x=t2*(a+b*tmp1);
      gradient_structure::GRAD_STACK1->set_gradient_stack(
        default_evaluation,&(RETURN_PTR->v->x),
        &(v1.v->x),tmp1*(2*a+3*b*tmp1));
    }
  }
  return *RETURN_PTR;
}

prevariable& cos(const prevariable& v1)
{
  dvariable* RETURN_PTR = gradient_structure::next_RETURN_PTR();

  RETURN_PTR->v->x=::cos(v1.v->x);
  gradient_structure::GRAD_STACK1->set_gradient_stack(
    default_evaluation,&(RETURN_PTR->v->x),
    &(v1.v->x),-::sin(v1.v->x) );

  return *RETURN_PTR;
}

prevariable& log(const prevariable& v1)
{
  dvariable* RETURN_PTR = gradient_structure::next_RETURN_PTR();

  RETURN_PTR->v->x=::log(v1.v->x);
  gradient_structure::GRAD_STACK1->set_gradient_stack(
    default_evaluation,&(RETURN_PTR->v->x),
    &(v1.v->x),1./(v1.v->x) );

  return *RETURN_PTR;
}

prevariable& log10(const prevariable& v1)
{
  dvariable* RETURN_PTR = gradient_structure::next_RETURN_PTR();

  RETURN_PTR->v->x=::log10(v1.v->x);
  gradient_structure::GRAD_STACK1->set_gradient_stack(default_evaluation,
    &(RETURN_PTR->v->x),&(v1.v->x),
    1./(v1.v->x)/2.3025851);

  return *RETURN_PTR;
}