/*-------------------------------------------------------------------------
  Scientific Computation Research Center, RPI, Troy NY
  (C) Copyright 1995, RPI-SCOREC
 
  Project  : shapeFuntions
  Author(s): Saikat Dey
  Creation : Oct., 95
  Modifi.  : 
  Function :
             return the derivative of the parametric transformation from
             element to entity coordinate systems.
-------------------------------------------------------------------------*/

#include <math.h>
#include "shapeFuncInternals.h"

#ifdef __cplusplus
extern "C" {
#endif

static int SF_par_TABLE[][3][2] = {
   {{0,0},{0,0},{0,0}},
   {{1,0},{0,1},{0,0}},
   {{1,0},{0,0},{0,1}},
   {{1,-1},{0,-1},{0,-1}},
   {{0,0},{0,0},{0,0}},
   {{0,0},{0,0},{0,0}},
   {{0,0},{0,0},{0,0}},
   {{0,0},{0,0},{0,0}},
   {{0,0},{0,0},{0,0}},
   {{0,0},{0,0},{0,0}},
   {{0,1},{1,0},{0,0}},
   {{0,0},{0,0},{0,0}},
   {{0,0},{1,0},{0,1}},
   {{0,-1},{1,-1},{0,-1}}, 
   {{0,0},{0,0},{0,0}},
   {{0,0},{0,0},{0,0}},
   {{0,0},{0,0},{0,0}},
   {{0,0},{0,0},{0,0}},
   {{0,0},{0,0},{0,0}},
   {{0,0},{0,0},{0,0}},
   {{0,1},{0,0},{1,0}},
   {{0,0},{0,1},{1,0}},
   {{0,0},{0,0},{0,0}},
   {{0,-1},{0,-1},{1,-1}},
   {{0,0},{0,0},{0,0}},
   {{0,0},{0,0},{0,0}},
   {{0,0},{0,0},{0,0}},
   {{0,0},{0,0},{0,0}},
   {{0,0},{0,0},{0,0}},
   {{0,0},{0,0},{0,0}},
   {{-1,1},{-1,0},{-1,0}},
   {{-1,0},{-1,1},{-1,0}},
   {{-1,0},{-1,0},{-1,1}}
};

int E_parDrv(int i, int j, int type, double drv[][2]) {
  int ind[2],ii;
  /* find out type of element */
  if( type == Sedge )
    return 0;
  else if( type == Stri ) {
    drv[0][0] = drv[0][1] = drv[1][0] = drv[1][1] = 0.0;
    if( i == 0 && j == 1 ) { /* edge +0 , xi = s-r */
      drv[0][0] = 1.0;
      drv[1][1] = 1.0;
    } else if( i == 1 && j == 0 ) { /* edge -0 , xi = r-s */
      drv[0][1] = 1.0;
      drv[1][0] = 1.0;
    } else if( i == 1 && j == 2 ) { /* edge +1 , xi = t-s */
      drv[0][1] = -1.0;
      drv[1][0] = 1.0;
      drv[1][1] = -1.0;
    } else if( i == 2 && j == 1 ) { /* edge -1 , xi = s-t */
      drv[0][0] = -1.0;
      drv[1][0] = -1.0;
      drv[1][1] = 1.0;
    } else if( i == 2 && j == 0 ) { /* edge +2 , xi = r-t */
      drv[0][0] = -1.0;
      drv[0][1] = 1.0;
      drv[1][0] = -1.0;
    } else if( i == 0 && j == 2 ) { /* edge -2 , xi = t-r */
      drv[0][0] = 1.0;
      drv[0][1] = -1.0;
      drv[1][1] = -1.0;
    } else
      return 0;
    return 1;
  } else if( type == Stet ) {
    drv[0][0]=drv[0][1]=drv[1][0]=drv[1][1]=drv[2][0]=drv[2][1]=0.0;
    ind[0] = i; ind[1] = j;
    for(ii=0; ii<2; ii++) {
      if(ind[ii] == 0) /* r'= r */
	drv[0][ii] = 1.0;
      else if(ind[ii] == 1) /* r'= s */
	drv[1][ii] = 1.0;
      else if(ind[ii] == 2) /* r'= t */
	drv[2][ii] = 1.0;
      else if(ind[ii] == 3) /* r'= 1-r-s-t */
	drv[0][ii]=drv[1][ii]=drv[2][ii]=-1.0;
    }
    return 1;
  } else
    return 0;
}

int F_parDrv(int i, int j, int k, int type, int (**drv)[2]) {
  int index = 10*i + j;
  *drv = SF_par_TABLE[index] ;
  return 1;
}

#ifdef __cplusplus
}
#endif