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solve_rte.c

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  • solve_rte.c 14.42 KiB
    #include "iteration_functions.h"
    #include <gsl/gsl_interp2d.h>
    
    double I0_center_updown(double tau, double u);
    double I0_upward(double tau, double u);
    double I0_uniform_updown(double tau, double u);
    
    void set_spline2d_obj(gsl_spline2d* Spline_I2d, double* za, double** I_funct);
    int set_array_idx(double tau_prev, double tau, double* array, int nstep);
    
    double tau0;
    
    /*================================================================================*/
    
    void optimize_taustep(int k_iter, int seed_distribution)
    {
      Nstep_tau = 100;
    
      tau0 = disktau / 2.;
    
      while (solve_rte(k_iter, seed_distribution, Nstep_tau))
      {
        Nstep_tau = (int)Nstep_tau * 1.2;
      }
    }
    
    /*================================================================================*/
    
    int solve_rte(int k_iter, int seed_distribution, int Nstep_tau)
    {
    
      printf("\n\nReceveing Nstep_tau %d\n", Nstep_tau);
      int ii, jj, kk, status;
    
      Nstep_mu = 30;
      /* Nstep_tau = 100;*/
    
      tau0 = disktau / 2.;
    
      // printf("tau0=%4.3f\n", tau0);
    
      static double y[4];
      void* jac = NULL;
      double step_tau;
      double* array_tau;
      double* array_mu;
      double* array_weights;
    
      gsl_spline2d* Spline_I2d_l_upstream;
      gsl_spline2d* Spline_I2d_l_downstream;
      gsl_spline2d* Spline_I2d_r_upstream;
      gsl_spline2d* Spline_I2d_r_downstream;
    
      /*==============================================================================================*/
      float* roots = malloc((Nstep_mu + 1) * sizeof(float));
      float* weights = malloc((Nstep_mu + 1) * sizeof(float));
    
      array_mu = malloc(Nstep_mu * sizeof(double));
      array_weights = malloc(Nstep_mu * sizeof(double));
    
      gauleg(0, 1, roots, weights, Nstep_mu);
    
      for (ii = 1; ii <= Nstep_mu; ii++)
      {
        array_mu[ii - 1] = roots[ii];
        array_weights[ii - 1] = weights[ii];
        // printf("%lf 1 \n", array_mu[ii - 1]);
      }
    
      array_tau = malloc(Nstep_tau * sizeof(double));
      make_linarray(0, 2. * tau0, Nstep_tau, array_tau);
    
      Iklr_intensity* ptr_Iklr = malloc(k_iter * sizeof(Iklr_intensity));
    
      for (ii = 0; ii < k_iter; ii++)
      {
        ptr_Iklr[ii].Il_matrix_upstream = dmatrix(0, Nstep_tau - 1, 0, Nstep_mu - 1);
        ptr_Iklr[ii].Ir_matrix_upstream = dmatrix(0, Nstep_tau - 1, 0, Nstep_mu - 1);
    
        ptr_Iklr[ii].Il_matrix_downstream = dmatrix(0, Nstep_tau - 1, 0, Nstep_mu - 1);
        ptr_Iklr[ii].Ir_matrix_downstream = dmatrix(0, Nstep_tau - 1, 0, Nstep_mu - 1);
      }
    
      /*==============================================================================*/
    
      for (ii = 0; ii < Nstep_tau; ii++)
      {
        for (jj = 0; jj < Nstep_mu; jj++)
        {
          if (seed_distribution == SEED_CENTER)
          {
            ptr_Iklr[0].Il_matrix_upstream[ii][jj] = I0_center_updown(array_tau[ii], array_mu[jj]);
            ptr_Iklr[0].Ir_matrix_upstream[ii][jj] = I0_center_updown(array_tau[ii], array_mu[jj]);
    
            ptr_Iklr[0].Il_matrix_downstream[ii][jj] = I0_center_updown(array_tau[ii], array_mu[jj]);
            ptr_Iklr[0].Ir_matrix_downstream[ii][jj] = I0_center_updown(array_tau[ii], array_mu[jj]);
    
            /*if (jj==10)
            {
                printf("tau=%5.4f I=%5.4e\n", array_tau[ii], ptr_Iklr[0].Il_matrix_upstream[ii][jj]);
            }*/
          }
          else if (seed_distribution == SEED_UNIFORM)
          {
            ptr_Iklr[0].Il_matrix_upstream[ii][jj] = I0_uniform_updown(array_tau[ii], array_mu[jj]);
            ptr_Iklr[0].Ir_matrix_upstream[ii][jj] = I0_uniform_updown(array_tau[ii], array_mu[jj]);
    
            ptr_Iklr[0].Il_matrix_downstream[ii][jj] = I0_uniform_updown(array_tau[ii], array_mu[jj]);
            ptr_Iklr[0].Ir_matrix_downstream[ii][jj] = I0_uniform_updown(array_tau[ii], array_mu[jj]);
          }
    
          else if (seed_distribution == SEED_BASE)
          {
            ptr_Iklr[0].Il_matrix_upstream[ii][jj] = I0_upward(array_tau[ii], array_mu[jj]);
            ptr_Iklr[0].Ir_matrix_upstream[ii][jj] = I0_upward(array_tau[ii], array_mu[jj]);
    
            ptr_Iklr[0].Il_matrix_downstream[ii][jj] = 0;
            ptr_Iklr[0].Ir_matrix_downstream[ii][jj] = 0;
          }
          else
          {
            printf(
                "Error: please select seed=4 (photons at the base) or seed=2 (uniform distribution)\n");
            exit(1);
          }
        }
      }
    
    
    
      /*=================================================================*/
      /*Setup for 2D interpolation*/
      /*=================================================================*/
    
      double* Il_upstream_za = malloc(Nstep_tau * Nstep_mu * sizeof(double));
      double* Il_downstream_za = malloc(Nstep_tau * Nstep_mu * sizeof(double));
      double* Ir_upstream_za = malloc(Nstep_tau * Nstep_mu * sizeof(double));
      double* Ir_downstream_za = malloc(Nstep_tau * Nstep_mu * sizeof(double));
    
      const gsl_interp2d_type* T_interp2d = gsl_interp2d_bilinear;
    
      Spline_I2d_l_upstream = gsl_spline2d_alloc(T_interp2d, Nstep_tau, Nstep_mu);
      Spline_I2d_l_downstream = gsl_spline2d_alloc(T_interp2d, Nstep_tau, Nstep_mu);
    
      Spline_I2d_r_upstream = gsl_spline2d_alloc(T_interp2d, Nstep_tau, Nstep_mu);
      Spline_I2d_r_downstream = gsl_spline2d_alloc(T_interp2d, Nstep_tau, Nstep_mu);
    
      xacc_2d = gsl_interp_accel_alloc();
      yacc_2d = gsl_interp_accel_alloc();
    
      step_tau = (2 * tau0) / Nstep_tau;
    
    
      Iklr_intensity* ptr_data = malloc(sizeof(Iklr_intensity));
      Iklr_intensity* params;
    
      // const gsl_odeiv_step_type* T = gsl_odeiv_step_rk4;
    
      /*================================================================================*/
      /*Start the loop over k-iterations*/
      /*================================================================================*/
    
      double tau, tau_prev;
      // step_tau = 0.01;
    
      for (kk = 1; kk < k_iter; kk++)
      {
        printf("Iteration k=%d....\n\n", kk);
    
        /*==========================================================================================*/
        /*Initialize the spline for 2D interpolation for Il(tau,u)^{k-1} and Ir(tau,u)^{k-1}*/
        /*both for upward and downward intensities*/
        /*==========================================================================================*/
    
        set_spline2d_obj(Spline_I2d_l_upstream, Il_upstream_za, ptr_Iklr[kk - 1].Il_matrix_upstream);
        set_spline2d_obj(Spline_I2d_l_downstream, Il_downstream_za, ptr_Iklr[kk - 1].Il_matrix_downstream);
    
        set_spline2d_obj(Spline_I2d_r_upstream, Ir_upstream_za, ptr_Iklr[kk - 1].Ir_matrix_upstream);
        set_spline2d_obj(Spline_I2d_r_downstream, Ir_downstream_za, ptr_Iklr[kk - 1].Ir_matrix_downstream);
    
        gsl_spline2d_init(Spline_I2d_l_upstream, array_tau, array_mu, Il_upstream_za, Nstep_tau, Nstep_mu);
        gsl_spline2d_init(Spline_I2d_l_downstream, array_tau, array_mu, Il_downstream_za, Nstep_tau, Nstep_mu);
    
        gsl_spline2d_init(Spline_I2d_r_upstream, array_tau, array_mu, Ir_upstream_za, Nstep_tau, Nstep_mu);
        gsl_spline2d_init(Spline_I2d_r_downstream, array_tau, array_mu, Ir_downstream_za, Nstep_tau, Nstep_mu);
    
        ptr_data->Spline_I2d_l_upstream = Spline_I2d_l_upstream;
        ptr_data->Spline_I2d_l_downstream = Spline_I2d_l_downstream;
    
        ptr_data->Spline_I2d_r_upstream = Spline_I2d_r_upstream;
        ptr_data->Spline_I2d_r_downstream = Spline_I2d_r_downstream;
    
    
        /*=======================================================================*/
        /*Solve the RTE at the quadrature points*/
        /*=======================================================================*/
    
        status = GSL_SUCCESS + 1;
    
        //gsl_set_error_handler_off();
    
        for (jj = 0; jj < Nstep_mu; jj++)
        {
          // printf("\nSolve system for u=%4.3f\n", array_mu[jj]);
    
          ptr_data->u = array_mu[jj];
          ptr_data->array_u = array_mu;
          ptr_data->weights_u = array_weights;
    
          params = ptr_data;
    
          /*======================================*/
          /*Initial boundary conditions*/
          /*======================================*/
    
          tau = 0;
          tau_prev = 0;
          int idx;
    
          y[0] = 0;
          y[1] = 0;
          y[2] = 0;
          y[3] = 0;
    
          gsl_odeiv2_system sys = {RTE_Equations, jac, 4, params};
          gsl_odeiv2_driver* d = gsl_odeiv2_driver_alloc_y_new(&sys, gsl_odeiv2_step_rk8pd, step_tau, 1e-4, 1e-4);
    
          while (tau < 2 * tau0)
          {
            // printf("tau prima %lf\n", tau);
    
            status = gsl_odeiv2_driver_apply_fixed_step(d, &tau, step_tau, 1, y);
    
            if (status)
            {
              printf("Error during integration: %s\n", gsl_strerror(status));
              // printf("Status %d\n", status);
              return (1);
            }
    
            idx = set_array_idx(tau_prev, tau, array_tau, Nstep_tau);
    
            if (idx > 0)
            {
              ptr_Iklr[kk].Il_matrix_upstream[idx][jj] = y[0];
              ptr_Iklr[kk].Ir_matrix_upstream[idx][jj] = y[1];
    
              ptr_Iklr[kk].Il_matrix_downstream[idx][jj] = y[2];
              ptr_Iklr[kk].Ir_matrix_downstream[idx][jj] = y[3];
            }
    
            tau_prev = tau;
          }
    
          gsl_odeiv2_driver_free(d);
    
        } // End of loop over array_mu
    
      } // End of loop over k_iter
    
      Ikl_intensity* ptr_a = 0;
      Ikr_intensity* ptr_b = 0;
    
      compute_results(1, k_iter, Nstep_tau, Nstep_mu, array_mu, array_weights, ptr_Iklr, ptr_a, ptr_b);
    
      free(Il_upstream_za);
      free(Il_downstream_za);
      free(Ir_upstream_za);
      free(Ir_downstream_za);
      free(array_tau);
      free(ptr_Iklr);
    
      gsl_spline2d_free(Spline_I2d_l_upstream);
      gsl_spline2d_free(Spline_I2d_l_downstream);
      gsl_spline2d_free(Spline_I2d_r_upstream);
      gsl_spline2d_free(Spline_I2d_r_downstream);
    
    
      return 0;
    }
    
    /*================================================================================*/
    /*Solution of equations (4.206) and (4.207) of Pomraning 1973*/
    /*================================================================================*/
    
    int RTE_Equations(double s, const double y[], double f[], void* params)
    {
      double* array_u = ((Iklr_intensity*)params)->array_u;
      double* weights_u = (double*)((Iklr_intensity*)params)->weights_u;
      double u = ((Iklr_intensity*)params)->u;
    
      gsl_spline2d* Spline_I2d_l_upstream = ((Iklr_intensity*)params)->Spline_I2d_l_upstream;
      gsl_spline2d* Spline_I2d_l_downstream = ((Iklr_intensity*)params)->Spline_I2d_l_downstream;
    
      gsl_spline2d* Spline_I2d_r_upstream = ((Iklr_intensity*)params)->Spline_I2d_r_upstream;
      gsl_spline2d* Spline_I2d_r_downstream = ((Iklr_intensity*)params)->Spline_I2d_r_downstream;
    
    
      /*==============================================*/
      /*Equation for I_l  upstream*/
      /*==============================================*/
    
      //printf("UNO  s=%lf\n");
    
    
      f[0] = -1 / u * y[0] +
             3 / (8 * u) *
                 (legendre_integration_A(Spline_I2d_l_upstream, s, u, array_u, weights_u) +
                  legendre_integration_A(Spline_I2d_l_downstream, 2 * tau0 - s, u, array_u, weights_u) +
    
                  legendre_integration_B(Spline_I2d_r_upstream, s, u, array_u, weights_u) +
                  legendre_integration_B(Spline_I2d_r_downstream, 2 * tau0 - s, u, array_u, weights_u));
    
    
    
      //printf("UNO DOPO  s=%10.7f\n");
    
      /*==============================================*/
      /*Equation for I_r upstream*/
      /*==============================================*/
    
    
    
      f[1] = -1 / u * y[1] +
             3 / (8 * u) *
                 (legendre_integration_C(Spline_I2d_l_upstream, s, u, array_u, weights_u) +
                  legendre_integration_C(Spline_I2d_l_downstream, 2 * tau0 - s, u, array_u, weights_u) +
                  legendre_integration_D(Spline_I2d_r_upstream, s, u, array_u, weights_u) +
                  legendre_integration_D(Spline_I2d_r_downstream, 2 * tau0 - s, u, array_u, weights_u));
    
      /*==============================================*/
      /*Equation for I_l downstream*/
      /*==============================================*/
    
    
    
      f[2] = -1 / u * y[2] +
             3 / (8 * u) *
                 (legendre_integration_A(Spline_I2d_l_downstream, s, u, array_u, weights_u) +
                  legendre_integration_A(Spline_I2d_l_upstream, 2 * tau0 - s, u, array_u, weights_u) +
    
                  legendre_integration_B(Spline_I2d_r_downstream, s, u, array_u, weights_u) +
                  legendre_integration_B(Spline_I2d_r_upstream, 2 * tau0 - s, u, array_u, weights_u));
    
      /*==============================================*/
      /*Equation for I_r downstream*/
      /*==============================================*/
    
    
    
      f[3] = -1 / u * y[3] +
             3 / (8 * u) *
                 (legendre_integration_C(Spline_I2d_l_downstream, s, u, array_u, weights_u) +
                  legendre_integration_C(Spline_I2d_l_upstream, 2 * tau0 - s, u, array_u, weights_u) +
    
                  legendre_integration_D(Spline_I2d_r_downstream, s, u, array_u, weights_u) +
                  legendre_integration_D(Spline_I2d_r_upstream, 2 * tau0 - s, u, array_u, weights_u));
    
      // printf("SLURM tau=%lf u=%5.4f f[0]=%5.4e f[1]=%5.4e f[2]=%5.4e f[3]=%5.4e\n", s, u, f[0], f[1], f[2], f[3]);
    
      return GSL_SUCCESS;
    }
    
    /*====================================================================*/
    /*Value of the I^k(tau,u) function for k=0 and seed photons*/
    /*at the base of the slab (tau=0)*/
    /*====================================================================*/
    
    double I0_upward(double tau, double u)
    {
      double value;
    
      if (tau == 0)
      {
        value = 0;
      }
      else
      {
        value = 1 / 2. * 1 / u * exp(-tau / u);
      }
    
      return value;
    }
    
    /*====================================================================*/
    /*Value of the I^k(tau,u) function for k=0 and seed photons*/
    /*uniformly distributed*/
    /*====================================================================*/
    
    double I0_uniform_updown(double tau, double u)
    {
      double value;
    
      value = 1 / 2. * (1 - exp(-tau / u));
    
      return value;
    }
    
    /*====================================================================*/
    /*Value of the I^k(tau,u) function for k=0 and seed photons*/
    /*uniformly distributed*/
    /*====================================================================*/
    
    double I0_center_updown(double tau, double u)
    {
      double value;
    
      if (tau >= tau0)
      {
        value = 1 / 2. * 1 / u * exp(-(tau - tau0) / u);
      }
      else
      {
        value = 0;
      }
    
      return value;
    }
    
    /*==============================================================================*/
    void set_spline2d_obj(gsl_spline2d* Spline_I2d, double* za, double** I_funct)
    {
      int tt, qq;
    
      for (tt = 0; tt < Nstep_tau; tt++)
      {
        for (qq = 0; qq < Nstep_mu; qq++)
        {
          /*printf("tt=%d qq=%d funct=%4.3e\n", tt, qq, I_funct[tt][qq]); */
          gsl_spline2d_set(Spline_I2d, za, tt, qq, I_funct[tt][qq]);
        }
      }
    }
    
    int set_array_idx(double tau_prev, double tau, double* array, int nstep)
    {
      int idx, ii;
    
      idx = -1;
    
      if (tau_prev == array[0])
      {
        idx = 0;
      }
      else if (tau == array[nstep - 1])
      {
        idx = nstep - 1;
      }
      else
      {
        for (ii = 1; ii < nstep; ii++)
        {
          if (tau_prev <= array[ii] && tau >= array[ii])
          {
            idx = ii;
            // printf("Sono qui tau_prev %4.3f tau %4.3f array[ii] %4.3f idx %d\n", tau_prev, tau,
            //		array[ii], idx);
    
            break;
          }
        }
      }
    
      return idx;
    }