CoordTransf.cpp

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/* TwoPunctures:  File  "CoordTransf.c"*/
 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <ctype.h>
#include <time.h>
#include <gsl/gsl_complex.h>
#include <gsl/gsl_complex_math.h>
#include "libtwopunctures/TwoPunctures.h"
 
namespace TP {
using namespace Utilities;
 
/*-----------------------------------------------------------*/
void
TwoPunctures::AB_To_XR (int nvar, double A, double B, double *X, double *R,
      derivs U)
/* On Entrance: U.d0[]=U[]; U.d1[] =U[]_A;  U.d2[] =U[]_B;  U.d3[] =U[]_3;  */
/*                          U.d11[]=U[]_AA; U.d12[]=U[]_AB; U.d13[]=U[]_A3; */
/*                          U.d22[]=U[]_BB; U.d23[]=U[]_B3; U.d33[]=U[]_33; */
/* At Exit:     U.d0[]=U[]; U.d1[] =U[]_X;  U.d2[] =U[]_R;  U.d3[] =U[]_3;  */
/*                          U.d11[]=U[]_XX; U.d12[]=U[]_XR; U.d13[]=U[]_X3; */
/*                          U.d22[]=U[]_RR; U.d23[]=U[]_R3; U.d33[]=U[]_33; */
{
  
  double At = 0.5 * (A + 1), A_X, A_XX, B_R, B_RR;
  int ivar;
 
  *X = 2 * atanh (At);
  *R = Pih + 2 * atan (B);
 
  A_X = 1 - At * At;
  A_XX = -At * A_X;
  B_R = 0.5 * (1 + B * B);
  B_RR = B * B_R;
 
  for (ivar = 0; ivar < nvar; ivar++)
  {
    U.d11[ivar] = A_X * A_X * U.d11[ivar] + A_XX * U.d1[ivar];
    U.d12[ivar] = A_X * B_R * U.d12[ivar];
    U.d13[ivar] = A_X * U.d13[ivar];
    U.d22[ivar] = B_R * B_R * U.d22[ivar] + B_RR * U.d2[ivar];
    U.d23[ivar] = B_R * U.d23[ivar];
    U.d1[ivar] = A_X * U.d1[ivar];
    U.d2[ivar] = B_R * U.d2[ivar];
  }
}
 
/*-----------------------------------------------------------*/
void
TwoPunctures::C_To_c (int nvar, double X, double R, double *x, double *r,
    derivs U)
/* On Entrance: U.d0[]=U[]; U.d1[] =U[]_X;  U.d2[] =U[]_R;  U.d3[] =U[]_3;  */
/*                          U.d11[]=U[]_XX; U.d12[]=U[]_XR; U.d13[]=U[]_X3; */
/*                          U.d22[]=U[]_RR; U.d23[]=U[]_R3; U.d33[]=U[]_33; */
/* At Exit:     U.d0[]=U[]; U.d1[] =U[]_x;  U.d2[] =U[]_r;  U.d3[] =U[]_3;  */
/*                          U.d11[]=U[]_xx; U.d12[]=U[]_xr; U.d13[]=U[]_x3; */
/*                          U.d22[]=U[]_rr; U.d23[]=U[]_r3; U.d33[]=U[]_33; */
{
  
  double C_c2, U_cb, U_CB;
  gsl_complex C, C_c, C_cc, c, c_C, c_CC, U_c, U_cc, U_C, U_CC;
  int ivar;
 
  C = gsl_complex_rect (X, R);
 
  c = gsl_complex_mul_real (gsl_complex_cosh (C), par_b);   /* c=b*cosh(C)*/
  c_C = gsl_complex_mul_real (gsl_complex_sinh (C), par_b);
  c_CC = c;
 
  C_c = gsl_complex_inverse (c_C);
  C_cc = gsl_complex_negative (gsl_complex_mul (gsl_complex_mul (C_c, C_c), gsl_complex_mul (C_c, c_CC)));
  C_c2 = gsl_complex_abs2 (C_c);
 
  for (ivar = 0; ivar < nvar; ivar++)
  {
    /* U_C = 0.5*(U_X3-i*U_R3)*/
    /* U_c = U_C*C_c = 0.5*(U_x3-i*U_r3)*/
    U_C = gsl_complex_rect (0.5 * U.d13[ivar], -0.5 * U.d23[ivar]);
    U_c = gsl_complex_mul (U_C, C_c);
    U.d13[ivar] = 2. * GSL_REAL(U_c);
    U.d23[ivar] = -2. * GSL_IMAG(U_c);
 
    /* U_C = 0.5*(U_X-i*U_R)*/
    /* U_c = U_C*C_c = 0.5*(U_x-i*U_r)*/
    U_C = gsl_complex_rect (0.5 * U.d1[ivar], -0.5 * U.d2[ivar]);
    U_c = gsl_complex_mul (U_C, C_c);
    U.d1[ivar] = 2. * GSL_REAL(U_c);
    U.d2[ivar] = -2. * GSL_IMAG(U_c);
 
    /* U_CC = 0.25*(U_XX-U_RR-2*i*U_XR)*/
    /* U_CB = d^2(U)/(dC*d\bar{C}) = 0.25*(U_XX+U_RR)*/
    U_CC = gsl_complex_rect (0.25 * (U.d11[ivar] - U.d22[ivar]), -0.5 * U.d12[ivar]);
    U_CB = 0.25 * (U.d11[ivar] + U.d22[ivar]);
 
    /* U_cc = C_cc*U_C+(C_c)^2*U_CC*/
    U_cb = U_CB * C_c2;
    U_cc = gsl_complex_add (gsl_complex_mul (C_cc, U_C), gsl_complex_mul (gsl_complex_mul (C_c, C_c), U_CC));
 
    /* U_xx = 2*(U_cb+Re[U_cc])*/
    /* U_rr = 2*(U_cb-Re[U_cc])*/
    /* U_rx = -2*Im[U_cc]*/
    U.d11[ivar] = 2 * (U_cb + GSL_REAL(U_cc));
    U.d22[ivar] = 2 * (U_cb - GSL_REAL(U_cc));
    U.d12[ivar] = -2 * GSL_IMAG(U_cc);
  }
 
  *x = GSL_REAL(c);
  *r = GSL_IMAG(c);
}
 
/*-----------------------------------------------------------*/
void
TwoPunctures::rx3_To_xyz (int nvar, double x, double r, double phi,
        double *y, double *z, derivs U)
/* On Entrance: U.d0[]=U[]; U.d1[] =U[]_x;  U.d2[] =U[]_r;  U.d3[] =U[]_3;  */
/*                          U.d11[]=U[]_xx; U.d12[]=U[]_xr; U.d13[]=U[]_x3; */
/*                          U.d22[]=U[]_rr; U.d23[]=U[]_r3; U.d33[]=U[]_33; */
/* At Exit:     U.d0[]=U[]; U.d1[] =U[]_x;  U.d2[] =U[]_y;  U.dz[] =U[]_z;  */
/*                          U.d11[]=U[]_xx; U.d12[]=U[]_xy; U.d1z[]=U[]_xz; */
/*                          U.d22[]=U[]_yy; U.d2z[]=U[]_yz; U.dzz[]=U[]_zz; */
{
  int jvar;
  double
    sin_phi = sin (phi),
    cos_phi = cos (phi),
    sin2_phi = sin_phi * sin_phi,
    cos2_phi = cos_phi * cos_phi,
    sin_2phi = 2 * sin_phi * cos_phi,
    cos_2phi = cos2_phi - sin2_phi, r_inv = 1 / r, r_inv2 = r_inv * r_inv;
 
  *y = r * cos_phi;
  *z = r * sin_phi;
 
  for (jvar = 0; jvar < nvar; jvar++)
  {
    double U_x = U.d1[jvar], U_r = U.d2[jvar], U_3 = U.d3[jvar],
      U_xx = U.d11[jvar], U_xr = U.d12[jvar], U_x3 = U.d13[jvar],
      U_rr = U.d22[jvar], U_r3 = U.d23[jvar], U_33 = U.d33[jvar];
    U.d1[jvar] = U_x;       /* U_x*/
    U.d2[jvar] = U_r * cos_phi - U_3 * r_inv * sin_phi; /* U_y*/
    U.d3[jvar] = U_r * sin_phi + U_3 * r_inv * cos_phi; /* U_z*/
    U.d11[jvar] = U_xx;     /* U_xx*/
    U.d12[jvar] = U_xr * cos_phi - U_x3 * r_inv * sin_phi;  /* U_xy*/
    U.d13[jvar] = U_xr * sin_phi + U_x3 * r_inv * cos_phi;  /* U_xz*/
    U.d22[jvar] = U_rr * cos2_phi + r_inv2 * sin2_phi * (U_33 + r * U_r)    /* U_yy*/
      + sin_2phi * r_inv2 * (U_3 - r * U_r3);
    U.d23[jvar] = 0.5 * sin_2phi * (U_rr - r_inv * U_r - r_inv2 * U_33) /* U_yz*/
      - cos_2phi * r_inv2 * (U_3 - r * U_r3);
    U.d33[jvar] = U_rr * sin2_phi + r_inv2 * cos2_phi * (U_33 + r * U_r)    /* U_zz*/
      - sin_2phi * r_inv2 * (U_3 - r * U_r3);
  }
}
 
/*-----------------------------------------------------------*/
 
} // namespace TP