pmlfunctions.c

a full 3D simulation of electromagnetic waves with efficient absorbing boundary a full 3D simulation

/* Copyright notice:
   radarFDTD - A free 3D-FDTD simulation for EM-waves with GPML-ABCs ;-)
   Copyright (C) 2000 Carsten Aulbert
   ( 
   I used the following program as a 'manual', so in my opinion this needs to be quoted:
   ToyFDTD, version 1.02 
   The if-I-can-do-it-you-can-do-it FDTD! 
   Copyright (C) 1998,1999 Laurie E. Miller, Paul Hayes, Matthew O'Keefe 
   )

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

PRECISION ReturnStretching (PRECISION position, PRECISION pmlThickness, PRECISION maxStretching, int stretchSteepness)
{
  /* I use the profile discribed in: Fang and Wu, Generlized PML for the Absorpion of Porpagating and Evanescent Waves, IEEE Transactions on Microwave Theory and Techniques, Volume 44, No.12, December 1996 */

  /* formula for this profile: s(pos) = 1 + s_max * (pos / thickness)**steepness */
  PRECISION tmp = 1.0 + maxStretching * pow(position / pmlThickness, stretchSteepness);
  return tmp;
}

PRECISION ReturnConductivity (PRECISION position, PRECISION pmlThickness, PRECISION maxConductivity)
{
  /* I use the profile discribed in: Fang and Wu, Generlized PML for the Absorpion of Porpagating and Evanescent Waves, IEEE Transactions on Microwave Theory and Techniques, Volume 44, No.12, December 1996 */

  PRECISION tmp = sin(M_PI * position / (2.0 * pmlThickness));
     return maxConductivity * tmp * tmp;
     /*  PRECISION tmp;
  
  switch(((int) (0.5+position/pmlThickness)))
    {
    case 0: tmp= 0.001064;break;
    case 1: tmp= 0.001210;break;
    case 2: tmp= 0.001296;break;
    case 3: tmp= 0.001385;break;
    case 4: tmp= 0.001487;break;
    case 5: tmp= 0.001606;break;
    case 6: tmp= 0.001746;break;
    case 7: tmp= 0.001916;break;
    case 8: tmp= 0.002126;break;
    case 9: tmp= 0.002395;break;
    case 10: tmp= 0.002752;break;
    case 11: tmp= 0.003257;break;
    case 12: tmp= 0.004040;break;
    case 13: tmp= 0.005446;break;
    case 14: tmp= 0.008747;break;
    case 15: tmp= 0.042007;break;
    default: tmp= 0.042007;
    }
    return tmp;*/
  
}