/****************************************************************************/
/* (C) Copyright 1993 Universidade Estadual de Campinas (UNICAMP)           */
/*                    Campinas, SP, Brazil                                  */
/*                                                                          */
/* This file can be freely distributed, modified, and used for any          */
/*   non-commercial purpose, provided that this copyright and authorship    */
/*   notice be included in any copy or derived version of this file.        */
/*                                                                          */
/* DISCLAIMER: This software is offered ``as is'', without any guarantee    */
/*   as to fitness for any particular purpose.  Neither the copyright       */
/*   holder nor the authors or their employers can be held responsible for  */
/*   any damages that may result from its use.                              */
/****************************************************************************/

char *aat_ftag = "f8";
char *aat_fname = 
  "f(x,y) = sum_i q_i / dist((x,y), (x_i, y_i))";

#define x1 (+0.500)
#define y1 (+0.500)
#define q1 (+1.000)

#define x2 (-0.500)
#define y2 (+0.250)
#define q2 (-0.875)

#define x3 (+0.500)
#define y3 (-0.125)
#define q3 (-0.750)

#define x4 (-0.500)
#define y4 (-0.375)
#define q4 (+0.625)

Float aat_d_flt (Float x, Float y, Float x0, Float y0);
Interval aat_d_ia (Interval x, Interval y, Float x0, Float y0);
AAP aat_d_aa (AAP x, AAP y, Float x0, Float y0);

Float aat_d_flt (Float x, Float y, Float x0, Float y0)
  { 
    ROUND_NEAR;
    {
      Float dx = x - x0;
      Float dy = y - y0;
      Float d = sqrt(dx*dx + dy*dy);
      return(d);
    }
  }
  
Float aat_f_flt (Float x, Float y)
  {
    ROUND_NEAR;
    {
      Float p1 = q1 / aat_d_flt (x, y, x1, y1);
      Float p2 = q2 / aat_d_flt (x, y, x2, y2);
      Float p3 = q3 / aat_d_flt (x, y, x3, y3);
      Float p4 = q4 / aat_d_flt (x, y, x4, y4);
      Float res = p1 + p2 + p3 + p4;
      return (res);
    }
  }

Interval aat_d_ia (Interval x, Interval y, Float x0, Float y0)
  { 
    Interval dx = ia_shift(x, -x0);
    Interval dy = ia_shift(y, -y0);
    Interval d = ia_sqrt(ia_add(ia_sqr(dx), ia_sqr(dy)));
    return(d);
  }
  
Interval aat_f_ia (Interval x, Interval y)
  {
    Interval p1 = ia_div(ia_const(q1, Zero), aat_d_ia (x, y, x1, y1));
    Interval p2 = ia_div(ia_const(q2, Zero), aat_d_ia (x, y, x2, y2));
    Interval p3 = ia_div(ia_const(q3, Zero), aat_d_ia (x, y, x3, y3));
    Interval p4 = ia_div(ia_const(q4, Zero), aat_d_ia (x, y, x4, y4));
    Interval res = ia_add(ia_add(p1, p2), ia_add(p3, p4));
    return (res);
  }

AAP aat_d_aa (AAP x, AAP y, Float x0, Float y0)
  { 
    AAP dx = aa_shift(x, -x0);
    AAP dy = aa_shift(y, -y0);
    AAP d = aa_sqrt(aa_add(aa_sqr(dx), aa_sqr(dy)));
    return(d);
  }
  
AAP aat_f_aa (AAP x, AAP y)
  {
    MemP frame = aa_top();
    AAP p1 = aa_div(aa_const(q1, Zero), aat_d_aa (x, y, x1, y1));
    AAP p2 = aa_div(aa_const(q2, Zero), aat_d_aa (x, y, x2, y2));
    AAP p3 = aa_div(aa_const(q3, Zero), aat_d_aa (x, y, x3, y3));
    AAP p4 = aa_div(aa_const(q4, Zero), aat_d_aa (x, y, x4, y4));
    AAP res = aa_add(aa_add(p1, p2), aa_add(p3, p4));
    return (aa_return(frame, res));
  }

Interval aat_fxd = {-Two, Two};
Interval aat_fyd = {-Two, Two};

int aat_fn = 64;