/*******************************************************************************
*
*  McStas, neutron ray-tracing package
*  Copyright(C) 2007 Risoe National Laboratory.
*
* %I
* Written by: Mads Bertelsen
* Date: 20.08.15
* Version: $Revision: 0.1 $
* Origin: University of Copenhagen
*
* Port of the PowderN process to the Union components
*
* %D
*
* This Union_process is based on the PowderN.comp component originally written
*  by P. Willendrup, L. Chapon, K. Lefmann, A.B.Abrahamsen, N.B.Christensen,
*  E.M.Lauridsen.
*
* Part of the Union components, a set of components that work together and thus
*  sperates geometry and physics within McStas.
* The use of this component requires other components to be used.
*
* 1) One specifies a number of processes using process components like this one
* 2) These are gathered into material definitions using Union_make_material
* 3) Geometries are placed using Union_box / Union_cylinder, assigned a material
* 4) A Union_master component placed after all of the above
*
* Only in step 4 will any simulation happen, and per default all geometries
*  defined before the master, but after the previous will be simulated here.
*
* There is a dedicated manual available for the Union_components*
* Algorithm:
* Described elsewhere
*
* %P
* INPUT PARAMETERS:
* interact_fraction: [1]         How large a part of the scattering events should use this process 0-1 (sum of all processes in material = 1)
* packing_factor:    [1]         How dense is the material compared to optimal 0-1
* reflections:       [string]    Input file for reflections. No scattering if NULL or "" [string]
* delta_d_d:         [0/1]       Global relative delta_d_d/d broadening when the 'w' column is not available. Use 0 if ideal.
* Strain:            [ppm]       Global relative delta_d_d/d shift when the 'Strain' column is not available. Use 0 if ideal.
* format:            [no quotes] Name of the format, or list of column indexes (see Description).
* barns:             [1]         Flag to indicate if |F|^2 from 'reflections' is in barns or fm^2 (barns=1 for laz, barns=0 for lau type files).
* Vc:                [AA^3]      Volume of unit cell=nb atoms per cell/density of atoms.
* DW:                [1]         Global Debye-Waller factor when the 'DW' column is not available. Use 1 if included in F2
* weight:            [g/mol]     Atomic/molecular weight of material.
* density:           [g/cm^3]    Density of material. rho=density/weight/1e24*N_A.
* nb_atoms:          [1]         Number of sub-unit per unit cell, that is ratio of sigma for chemical formula to sigma per unit cell
* target_index:      [1]         Relative index of component to focus at, e.g. next is +1
* d_phi: [deg]         Angle corresponding to the vertical angular range to focus to, e.g. detector height. 0 for no focusing.
*
* CALCULATED PARAMETERS:
* V_rho:  [AA^-3] Atomic density
*
*
* %E
******************************************************************************/

DEFINE COMPONENT Powder_process

SETTING PARAMETERS(string reflections="NULL",packing_factor=1, Vc=0, delta_d_d=0, DW=0, nb_atoms=1, d_phi=0, density=0, weight=0, barns=1, Strain=0, interact_fraction=-1, vector format={0, 0, 0, 0, 0, 0, 0, 0, 0}, string init="init")


/* Neutron parameters: (x,y,z,vx,vy,vz,t,sx,sy,sz,p) */

SHARE
%{
#ifndef Union
#error "The Union_init component must be included before this Powder_process component"
#endif



// Share section of PowderN 8/3 2016 from McStas.org

  /* used for reading data table from file */
  %include "read_table-lib"
  %include "interoff-lib"
/* Declare structures and functions only once in each instrument. */
#ifndef POWDERN_DECL_UNION
#define POWDERN_DECL_UNION
/* format definitions in the order {j d F2 DW Dd inv2d q F strain} */
#ifndef Crystallographica
#define Crystallographica { 4,5,7,0,0,0,0,0,0 }
#define Fullprof          { 4,0,8,0,0,5,0,0,0 }
#define Lazy              {17,6,0,0,0,0,0,13,0 }
#define Undefined         { 0,0,0,0,0,0,0,0,0 }
#endif

  struct line_data_union
    {
      double F2;                  /* Value of structure factor */
      double q;                   /* Qvector */
      int j;                      /* Multiplicity */
      double DWfactor;            /* Debye-Waller factor */
      double w;                   /* Intrinsic line width */
      double Epsilon;             /* Strain=delta_d_d/d shift in ppm */
    };

  struct line_info_struct_union
    {
      struct line_data_union *list;     /* Reflection array */
      int  count;                  /* Number of reflections */
      double Dd;
      double DWfactor;
      double V_0;
      double rho;
      double at_weight;
      double at_nb;
      double sigma_a; // should not be used
      double sigma_i; // should not be used
      char   compname[256];
      double flag_barns;
      int    shape; /* 0 cylinder, 1 box, 2 sphere, 3 OFF file */
      int    column_order[9]; /* column signification */
      int    flag_warning;
      char   type;  /* interaction type of event t=Transmit, i=Incoherent, c=Coherent */
      double dq;    /* wavevector transfer [Angs-1] */
      double Epsilon; /* global strain in ppm */
      double XsectionFactor;
      double my_s_v2_sum;
      double my_a_v;
      double my_inc;
      double *w_v,*q_v, *my_s_v2;
      double radius_i,xwidth_i,yheight_i,zdepth_i; // not to be used, but still here
      double v; /* last velocity (cached) */
      double Nq;
      int    nb_reuses, nb_refl, nb_refl_count;
      double v_min, v_max;
      double xs_Nq[CHAR_BUF_LENGTH];
      double xs_sum[CHAR_BUF_LENGTH];
      double neutron_passed;
      long   xs_compute, xs_reuse, xs_calls;
    };

  off_struct offdata_union;
  
  // PN_list_compare *****************************************************************

  int PN_list_compare_union (void const *a, void const *b)
  {
     struct line_data_union const *pa = a;
     struct line_data_union const *pb = b;
     double s = pa->q - pb->q;
     
     if (!s) return 0;
     else    return (s < 0 ? -1 : 1);
  } /* PN_list_compare */

  int read_line_data_union(char *SC_file, struct line_info_struct_union *info)
  {
    struct line_data_union *list = NULL;
    int    size = 0;
    t_Table sTable; /* sample data table structure from SC_file */
    int    i=0;
    int    mult_count  =0;
    char   flag=0;
    double q_count=0, j_count=0, F2_count=0;
    char **parsing;
    int    list_count=0;

    if (!SC_file || !strlen(SC_file) || !strcmp(SC_file, "NULL")) {
      printf("PowderN: %s: Using incoherent elastic scattering only\n",info->compname);
      info->count = 0;
      return(0);
    }
    Table_Read(&sTable, SC_file, 1); /* read 1st block data from SC_file into sTable*/

    /* parsing of header */
    parsing = Table_ParseHeader(sTable.header,
      "Vc","V_0",
      "sigma_abs","sigma_a ",
      "sigma_inc","sigma_i ",
      "column_j",
      "column_d",
      "column_F2",
      "column_DW",
      "column_Dd",
      "column_inv2d", "column_1/2d", "column_sintheta/lambda",
      "column_q", /* 14 */
      "DW", "Debye_Waller",
      "delta_d_d/d",
      "column_F ",
      "V_rho",
      "density",
      "weight",
      "nb_atoms","multiplicity", /* 23 */
      "column_ppm","column_strain",
      NULL);

    if (parsing) {
      if (parsing[0] && !info->V_0)     info->V_0    =atof(parsing[0]);
      if (parsing[1] && !info->V_0)     info->V_0    =atof(parsing[1]);
      if (parsing[2] && !info->sigma_a) info->sigma_a=atof(parsing[2]);
      if (parsing[3] && !info->sigma_a) info->sigma_a=atof(parsing[3]);
      if (parsing[4] && !info->sigma_i) info->sigma_i=atof(parsing[4]);
      if (parsing[5] && !info->sigma_i) info->sigma_i=atof(parsing[5]);
      if (parsing[6])                   info->column_order[0]=atoi(parsing[6]);
      if (parsing[7])                   info->column_order[1]=atoi(parsing[7]);
      if (parsing[8])                   info->column_order[2]=atoi(parsing[8]);
      if (parsing[9])                   info->column_order[3]=atoi(parsing[9]);
      if (parsing[10])                  info->column_order[4]=atoi(parsing[10]);
      if (parsing[11])                  info->column_order[5]=atoi(parsing[11]);
      if (parsing[12])                  info->column_order[5]=atoi(parsing[12]);
      if (parsing[13])                  info->column_order[5]=atoi(parsing[13]);
      if (parsing[14])                  info->column_order[6]=atoi(parsing[14]);
      if (parsing[15] && info->DWfactor<=0)    info->DWfactor=atof(parsing[15]);
      if (parsing[16] && info->DWfactor<=0)    info->DWfactor=atof(parsing[16]);
      if (parsing[17] && info->Dd <0)          info->Dd      =atof(parsing[17]);
      if (parsing[18])                  info->column_order[7]=atoi(parsing[18]);
      if (parsing[19] && !info->V_0)    info->V_0    =1/atof(parsing[19]);
      if (parsing[20] && !info->rho)    info->rho    =atof(parsing[20]);
      if (parsing[21] && !info->at_weight)     info->at_weight    =atof(parsing[21]);
      if (parsing[22] && info->at_nb <= 1)  info->at_nb    =atof(parsing[22]);
      if (parsing[23] && info->at_nb <= 1)  info->at_nb    =atof(parsing[23]);
      if (parsing[24])                  info->column_order[8]=atoi(parsing[24]);
      if (parsing[25])                  info->column_order[8]=atoi(parsing[25]);
      for (i=0; i<=25; i++) if (parsing[i]) free(parsing[i]);
      free(parsing);
    }

    if (!sTable.rows)
      exit(fprintf(stderr, "PowderN: %s: Error: The number of rows in %s "
       "should be at least %d\n", info->compname, SC_file, 1));
    else size = sTable.rows;
    Table_Info(sTable);
    printf("PowderN: %s: Reading %d rows from %s\n",
          info->compname, size, SC_file);

    if (info->column_order[0] == 4 && info->flag_barns !=0)
    printf("PowderN: %s: Powder file probably of type Crystallographica/Fullprof (lau)\n"
           "WARNING: but F2 unit is set to barns=1 (barns). Intensity might be 100 times too high.\n",
           info->compname);
  if (info->column_order[0] == 17 && info->flag_barns == 0)
    printf("PowderN: %s: Powder file probably of type Lazy Pulver (laz)\n"
           "WARNING: but F2 unit is set to barns=0 (fm^2). Intensity might be 100 times too low.\n",
           info->compname);
    /* allocate line_data array */
    list = (struct line_data_union*)malloc(size*sizeof(struct line_data_union));

    for (i=0; i<size; i++)
    {
      /*      printf("Reading in line %i\n",i);*/
      double j=0, d=0, w=0, q=0, DWfactor=0, F2=0, Epsilon=0;
      int index;

      if (info->Dd >= 0)      w         = info->Dd;
      if (info->DWfactor > 0) DWfactor  = info->DWfactor;
      if (info->Epsilon)      Epsilon   = info->Epsilon*1e-6;

      /* get data from table using columns {j d F2 DW Dd inv2d q F} */
      /* column indexes start at 1, thus need to substract 1 */
      if (info->column_order[0] >0)
        j = Table_Index(sTable, i, info->column_order[0]-1);
      if (info->column_order[1] >0)
        d = Table_Index(sTable, i, info->column_order[1]-1);
      if (info->column_order[2] >0)
        F2 = Table_Index(sTable, i, info->column_order[2]-1);
      if (info->column_order[3] >0)
        DWfactor = Table_Index(sTable, i, info->column_order[3]-1);
      if (info->column_order[4] >0)
        w = Table_Index(sTable, i, info->column_order[4]-1);
      if (info->column_order[5] >0)
        { d = Table_Index(sTable, i, info->column_order[5]-1);
          d = (d > 0? 1/d/2 : 0); }
      if (info->column_order[6] >0)
        { q = Table_Index(sTable, i, info->column_order[6]-1);
          d = (q > 0 ? 2*PI/q : 0); }
      if (info->column_order[7] >0  && !F2)
        { F2 = Table_Index(sTable, i, info->column_order[7]-1); F2 *= F2; }
      if (info->column_order[8] >0  && !Epsilon)
        { Epsilon = Table_Index(sTable, i, info->column_order[8]-1)*1e-6; }

      /* assign and check values */
      j        = (j > 0 ? j : 0);
      q        = (d > 0 ? 2*PI/d : 0); /* this is q */
      if (Epsilon && fabs(Epsilon) < 1e6) {
        q     -= Epsilon*q; /* dq/q = -delta_d_d/d = -Epsilon */
      }
      DWfactor = (DWfactor > 0 ? DWfactor : 1);
      w        = (w>0 ? w : 0); /* this is q and d relative spreading */
      F2       = (F2 >= 0 ? F2 : 0);
      if (j == 0 || q == 0) {
        printf("PowderN: %s: line %i has invalid definition\n"
               "         (mult=0 or q=0 or d=0)\n", info->compname, i);
        continue;
      }
      list[list_count].j = j;
      list[list_count].q = q;
      list[list_count].DWfactor = DWfactor;
      list[list_count].w = w;
      list[list_count].F2= F2;
      list[list_count].Epsilon = Epsilon;

      /* adjust multiplicity if j-column + multiple d-spacing lines */
      /* if  d = previous d, increase line duplication index */
      if (!q_count)      q_count  = q;
      if (!j_count)      j_count  = j;
      if (!F2_count)     F2_count = F2;
      if (fabs(q_count-q) < 0.0001*fabs(q)
       && fabs(F2_count-F2) < 0.0001*fabs(F2) && j_count == j) {
       mult_count++; flag=0; }
      else flag=1;
      if (i == size-1) flag=1;
      /* else if d != previous d : just passed equivalent lines */
      if (flag) {
        if (i == size-1) list_count++;
      /*   if duplication index == previous multiplicity */
      /*      set back multiplicity of previous lines to 1 */
        if ((mult_count && list_count>0)
            && (mult_count == list[list_count-1].j
                || ((list_count < size) && (i == size - 1)
                    && (mult_count == list[list_count].j))) ) {
          printf("PowderN: %s: Set multiplicity to 1 for lines [%i:%i]\n"
                  "         (d-spacing %g is duplicated %i times)\n",
            info->compname, list_count-mult_count, list_count-1, list[list_count-1].q, mult_count);
          for (index=list_count-mult_count; index<list_count; list[index++].j = 1);
          mult_count = 1;
          q_count   = q;
          j_count   = j;
          F2_count  = F2;
        }
        if (i == size-1) list_count--;
        flag=0;
      }
      list_count++;
    } /* end for */ 
    
    Table_Free(&sTable);
    
    /* sort the list with increasing q */
    qsort(list, list_count, sizeof(struct line_data_union),  PN_list_compare_union);
    
    printf("PowderN: %s: Read %i reflections from file '%s'\n", 
      info->compname, list_count, SC_file);
    
    info->list  = list;
    info->count = list_count;

    return(list_count);
  } /* read_line_data_union */


/* computes the number of possible reflections (return value), and the total xsection 'sum' */
/* this routine looks for a pre-computed value in the Nq and sum cache tables               */
/* when found, the earch starts from the corresponding lower element in the table           */
int calc_xsect_union(double v, double *qv, double *my_sv2, int count, double *sum,
  struct line_info_struct_union *line_info) {
  int    Nq = 0, line=0, line0=0;
  *sum=0;
  
  //printf("Line_info when entering cross_section calculation\n");
  //printf("v = %f, qv = %f, my_sv2 = %f, count = %d, sum = %f\n",v,*qv,*my_sv2,count,*sum);
  //printf("v = %f\n",v);
  //printf("line_info->v = %f, line_info->v_min = %f, line_info->v_max = %f, line_info->neutron_passed = %f\n",line_info->v,line_info->v_min,line_info->v_max,line_info->neutron_passed);
  //printf("line_info->xs_reuses = %d, line_info->xs_compute = %d\n",line_info->xs_reuse,line_info->xs_compute);
  
  
  /* check if a line_info element has been recorded already */
  if (v >= line_info->v_min && v <= line_info->v_max && line_info->neutron_passed >= CHAR_BUF_LENGTH) {
    line = (int)floor(v - line_info->v_min)*CHAR_BUF_LENGTH/(line_info->v_max - line_info->v_min);
    Nq    = line_info->xs_Nq[line];
    *sum  = line_info->xs_sum[line];
    if (!Nq && *sum == 0) {
      /* not yet set: we compute the sum up to the corresponding speed in the table cache */
      //printf("Nq and sum not yet set, have to do this calculation now\n");
      double line_v = line_info->v_min + line*(line_info->v_max - line_info->v_min)/CHAR_BUF_LENGTH;
      for(line0=0; line0<count; line0++) {
        if (qv[line0] <= 2*line_v) { /* q < 2*kf: restrict structural range */
          *sum += my_sv2[line0];
          if (Nq < line0+1) Nq=line0+1; /* determine maximum line index which can scatter */
        } else break;
      }
      line_info->xs_Nq[line] = Nq;
      line_info->xs_sum[line]= *sum;
      line_info->xs_compute++;
      //printf("line_info->xs_Nq[line] = %f, line_info->xs_sum[line] = %f, line_info->xs_compute = %d\n",line_info->xs_Nq[line],line_info->xs_sum[line],line_info->xs_compute);
    } else line_info->xs_reuse++;
    line0 = Nq;
  }
  
  line_info->xs_calls++;
  
  for(line=line0; line<count; line++) {
    if (qv[line] <= 2*v) { /* q < 2*kf: restrict structural range */
      *sum += my_sv2[line];
      if (Nq < line+1) Nq=line+1; /* determine maximum line index which can scatter */
    } else break;
  }
  
  //printf("cross_section function to return %d lines to scatter with, with cross section sum %f \n",Nq,*sum);
  return(Nq);
} /* calc_xsect_union */

#endif /* !POWDERN_DECL */



struct Powder_physics_storage_struct{
    // Variables that needs to be transfered between any of the following places:
    // The initialize in this component
    // The function for calculating my
    // The function for calculating scattering
    
    struct line_info_struct_union *line_info_storage;
    double my_scattering;
    double vertical_angular_limit;
};

// Obsolete: Function for initializing test_physics. Done in component instead.
int Powder_physics_initialize(union data_transfer_union data_transfer) {
      // Obsolte
      return 1;
};

// Function for calculating my in a test case.
int Powder_physics_my(double *my,double *k_initial, union data_transfer_union data_transfer, struct focus_data_struct *focus_data, _class_particle *_particle) {
    //*my = data_transfer.pointer_to_a_Powder_physics_storage_struct->my_scattering;
    
    
    int method_switch = 1;
    // For test
    int line_v,line0,line,count;
    
    // Should not interfer with the global variables
    double vx = k_initial[0]*K2V;
    double vy = k_initial[1]*K2V;
    double vz = k_initial[2]*K2V;
    
    // Not sure one can do this, but I do not see why not
    struct line_info_struct_union *line_info = data_transfer.pointer_to_a_Powder_physics_storage_struct->line_info_storage;
    
    double v = sqrt(vx*vx + vy*vy + vz*vz);
    //printf("Velocity = %f \n",v);
    
    //printf("line_info->v = %f, line_info->v_min = %f, line_info->v_max = %f, line_info->neutron_passed = %f\n",line_info->v,line_info->v_min,line_info->v_max,line_info->neutron_passed);
    // Here the maximum and minimum v is recorded, should this be for scattering events or cross section calculations?
    if (line_info->neutron_passed < CHAR_BUF_LENGTH) {
      if (v < line_info->v_min) line_info->v_min = v;
      if (v > line_info->v_max) line_info->v_max = v;
      line_info->neutron_passed++;
    }
    
    if (method_switch == 1) {
    // Here the cross section is calculated and stored
    if ( fabs(v - line_info->v) < 1e-6) {
        line_info->nb_reuses++;
      } else {
        //printf("calling crosssection calculation \n");
        // int calc_xsect_union(double v, double *qv, double *my_sv2, int count, double *sum, struct line_info_struct *line_info)
        line_info->Nq = calc_xsect_union(v, line_info->q_v, line_info->my_s_v2, line_info->count, &line_info->my_s_v2_sum, line_info);
        line_info->v = v;
        line_info->nb_refl += line_info->Nq;
        line_info->nb_refl_count++;
      }
    } else {
    if ( fabs(v - line_info->v) < 1e-6) {
        line_info->nb_reuses++;
      } else {
        //printf("calling crosssection calculation \n");
        if (v >= line_info->v_min && v <= line_info->v_max && line_info->neutron_passed >= CHAR_BUF_LENGTH) {
        line = (int)floor(v - line_info->v_min)*CHAR_BUF_LENGTH/(line_info->v_max - line_info->v_min);
        line_info->Nq = line_info->xs_Nq[line];
        line_info->my_s_v2_sum  = line_info->xs_sum[line];
        if (!line_info->Nq && line_info->my_s_v2_sum == 0) {
          /* not yet set: we compute the sum up to the corresponding speed in the table cache */
          //printf("Nq and sum not yet set, have to do this calculation now\n");
          double line_v = line_info->v_min + line*(line_info->v_max - line_info->v_min)/CHAR_BUF_LENGTH;
          for(line0=0; line0<count; line0++) {
            if (line_info->q_v[line0] <= 2*line_v) { /* q < 2*kf: restrict structural range */
              line_info->my_s_v2_sum += line_info->my_s_v2[line0];
              if (line_info->Nq < line0+1) line_info->Nq=line0+1; /* determine maximum line index which can scatter */
            } else break;
          }
          line_info->xs_Nq[line] = line_info->Nq;
          line_info->xs_sum[line]= line_info->my_s_v2_sum;
          line_info->xs_compute++;
          //printf("line_info->xs_Nq[line] = %f, line_info->xs_sum[line] = %f, line_info->xs_compute = %d\n",line_info->xs_Nq[line],line_info->xs_sum[line],line_info->xs_compute);
        } else line_info->xs_reuse++;
        line0 = line_info->Nq;
        }
          
        line_info->xs_calls++;
          
        for(line=line0; line<count; line++) {
          if (line_info->q_v[line] <= 2*v) { /* q < 2*kf: restrict structural range */
            line_info->my_s_v2_sum += line_info->my_s_v2[line];
            if (line_info->Nq < line+1) line_info->Nq=line+1; /* determine maximum line index which can scatter */
          } else break;
        }
        line_info->v = v;
        line_info->nb_refl += line_info->Nq;
        line_info->nb_refl_count++;
      }
    }
    
     *my = line_info->my_s_v2_sum/(v*v);
    //printf("Returned my scattering of %f \n",*my);
    //printf("compute = %d and reuse = %d \n",line_info->xs_compute,line_info->xs_reuse);
    
    return 1;
};

// Function that provides a basic nonuniform elastic scattering. Unphysical for testing purposes.
int Powder_physics_scattering(double *k_final, double *k_initial, double *weight, union data_transfer_union data_transfer, struct focus_data_struct *focus_data, _class_particle *_particle) {

    // This component need to write to its storage transfer for each event, is that possible with this structure?
    struct line_info_struct_union *line_info = data_transfer.pointer_to_a_Powder_physics_storage_struct->line_info_storage;
    double vertical_angular_limit = data_transfer.pointer_to_a_Powder_physics_storage_struct->vertical_angular_limit;
    
    
    // Should not interfer with the global variables
    double vx = k_initial[0]*K2V;
    double vy = k_initial[1]*K2V;
    double vz = k_initial[2]*K2V;
    
    double v = sqrt(vx*vx + vy*vy + vz*vz);
    
    int line;
    double arg;
    double theta;
    double alpha,alpha0;
    
    double vout_x,vout_y,vout_z;
    double tmp_vx,tmp_vy,tmp_vz;
    double nx,ny,nz;
    double my_s_n;
    
    // copy from PowderN component
    if (line_info->count > 0) {
          /* choose line */
          if (line_info->Nq > 1) line=floor(line_info->Nq*rand01());  /* Select between Nq powder lines */
          else line = 0;
          if (line_info->w_v[line])
            arg = line_info->q_v[line]*(1+line_info->w_v[line]*randnorm())/(2.0*v);
          else
            arg = line_info->q_v[line]/(2.0*v);
            my_s_n = line_info->my_s_v2[line]/(v*v);
          if(fabs(arg) > 1) {
            //printf("Powder scattering function returned 0, should not happen\n");
            return 0; /* No bragg scattering possible (was absorb)*/
          }
          theta = asin(arg);          /* Bragg scattering law */

          /* Choose point on Debye-Scherrer cone */
          if (vertical_angular_limit)
          { /* relate height of detector to the height on DS cone */
            arg = sin(vertical_angular_limit*DEG2RAD/2)/sin(2*theta);
            /* If full Debye-Scherrer cone is within d_phi, don't focus */
            if (arg < -1 || arg > 1) vertical_angular_limit = 0;
            /* Otherwise, determine alpha to rotate from scattering plane
               into vertical_angular_limit focusing area*/
            else alpha = 2*asin(arg);
          }
          if (vertical_angular_limit) {
            /* Focusing */
            alpha = fabs(alpha);
            /* Trick to get scattering for pos/neg theta's */
            alpha0= 2*rand01()*alpha;
            if (alpha0 > alpha) {
              alpha0=PI+(alpha0-1.5*alpha);
            } else {
              alpha0=alpha0-0.5*alpha;
            }
          }
          else
            alpha0 = PI*randpm1();

          /* now find a nearly vertical rotation axis:
           * Either
           *  (v along Z) x (X axis) -> nearly Y axis
           * Or
           *  (v along X) x (Z axis) -> nearly Y axis
           */
          if (fabs(scalar_prod(1,0,0,vx/v,vy/v,vz/v)) < fabs(scalar_prod(0,0,1,vx/v,vy/v,vz/v))) {
            nx = 1; ny = 0; nz = 0;
          } else {
            nx = 0; ny = 0; nz = 1;
          }
          vec_prod(tmp_vx,tmp_vy,tmp_vz, vx,vy,vz, nx,ny,nz);

          /* v_out = rotate 'v' by 2*theta around tmp_v: Bragg angle */
          rotate(vout_x,vout_y,vout_z, vx,vy,vz, 2*theta, tmp_vx,tmp_vy,tmp_vz);

          /* tmp_v = rotate v_out by alpha0 around 'v' (Debye-Scherrer cone) */
          rotate(tmp_vx,tmp_vy,tmp_vz, vout_x,vout_y,vout_z, alpha0, vx, vy, vz);
          vx = tmp_vx;
          vy = tmp_vy;
          vz = tmp_vz;
        
          k_final[0] = V2K*vx; k_final[1] = V2K*vy; k_final[2] = V2K*vz;
        
          //*weight *= line_info->Nq*my_s_n; I believe my_s_n is part of the correction for sampling posistion, not to be done here
          *weight *= line_info->Nq*my_s_n/line_info->my_s_v2_sum*v*v;
        
          //printf("my_s_n = %f \n",my_s_n);
        
          // What to do with my_s_n ?
          /*
          pmul  = line_info->Nq*l_full*my_s_n*exp(-(line_info->my_a_v/v+my_s)*(l+l_1))
                                  /(1-(p_inc+p_transmit));
          */
          // Correction in case of vertical_angular_limit focusing - BUT only when d_phi != 0
          if (vertical_angular_limit) *weight *= alpha/PI;
          
        
          line_info->type = 'c';
          line_info->dq = line_info->q_v[line]*V2K;
          
          
        } else {
        /* else transmit <-- No powder lines in file */
        printf("Error, need lines in the PowderN input file\n");
        }


    //printf("Powder scattering function returned 1\n");
    return 1;
};
#ifndef PROCESS_DETECTOR
    #define PROCESS_DETECTOR dummy
#endif

#ifndef PROCESS_POWDER_DETECTOR
    #define PROCESS_POWDER_DETECTOR dummy
#endif
%}

DECLARE
%{
// Needed for transport to the main component
struct global_process_element_struct global_process_element;
struct scattering_process_struct This_process;

// Declare for this component, to do calculations on the input / store in the transported data
struct Powder_physics_storage_struct Powder_storage;
struct line_info_struct_union line_info;
double effective_my_scattering;

double *columns;
%}

INITIALIZE
%{

  // Initialize done in the component
  columns = format;
  
  // Copy from PowderN component
  int i=0;
  struct line_data_union *L;
  line_info.Dd       = delta_d_d;
  line_info.DWfactor = DW;
  line_info.V_0      = Vc;
  line_info.rho      = density;
  line_info.at_weight= weight;
  line_info.at_nb    = nb_atoms;
  line_info.sigma_a  = 0; // This inputs are not needed, as absorption is handled elsewhere
  line_info.sigma_i  = 0; // This input is not needed, as incoherent scattering is handled elsewhere
  line_info.flag_barns=barns;
  //line_info.shape    = 0;
  line_info.flag_warning=0;
  line_info.Epsilon  = Strain;
  line_info.radius_i =line_info.xwidth_i=line_info.yheight_i=line_info.zdepth_i=0;
  line_info.v  = 0;
  line_info.Nq = 0;
  //line_info.v_min = FLT_MAX; line_info.v_max = 0;
  line_info.v_min = 10000000000; line_info.v_max = 0;
  line_info.neutron_passed=0;
  line_info.nb_reuses = line_info.nb_refl = line_info.nb_refl_count = 0;
  line_info.xs_compute= line_info.xs_reuse= line_info.xs_calls =0;
  for (i=0; i< 9; i++) line_info.column_order[i] = columns[i];
  strncpy(line_info.compname, NAME_CURRENT_COMP, 256);

  // p_interact handled elsewhere
  //if (p_interact) {
  //  if (p_interact < p_inc) { double tmp=p_interact; p_interact=p_inc; p_inc=tmp; }
  //  p_transmit = 1-p_interact-p_inc;
  //}

  if (reflections && strlen(reflections) && strcmp(reflections, "NULL") && strcmp(reflections, "0")) {
    i = read_line_data_union(reflections, &line_info);
    if (i == 0)
      exit(fprintf(stderr,"PowderN: %s: reflection file %s is not valid.\n"
                          "ERROR    Please check file format (laz or lau).\n", NAME_CURRENT_COMP, reflections));
  }

  /* compute the scattering unit density from material weight and density */
  /* the weight of the scattering element is the chemical formula molecular weight
   * times the nb of chemical formulae in the scattering element (nb_atoms) */
  if (!line_info.V_0 && line_info.at_nb > 0
    && line_info.at_weight > 0 && line_info.rho > 0) {
    /* molar volume [cm^3/mol] = weight [g/mol] / density [g/cm^3] */
    /* atom density per Angs^3 = [mol/cm^3] * N_Avogadro *(1e-8)^3 */
    line_info.V_0 = line_info.at_nb
      /(line_info.rho/line_info.at_weight/1e24*6.02214199e23);
  }

  /* the scattering unit cross sections are the chemical formula onces
   * times the nb of chemical formulae in the scattering element */
  if (line_info.at_nb > 0) {
    line_info.sigma_a *= line_info.at_nb; line_info.sigma_i *= line_info.at_nb;
  }

  if (line_info.V_0 <= 0)
    fprintf(stderr,"PowderN: %s: density/unit cell volume is NULL (Vc). Unactivating component.\n", NAME_CURRENT_COMP);


  if (line_info.flag_barns) { /* Factor 100 to convert from barns to fm^2 */
    line_info.XsectionFactor = 100;
  } else {
    line_info.XsectionFactor = 1;
  }

  if (line_info.V_0 && i) {
    L = line_info.list;

    line_info.q_v = malloc(line_info.count*sizeof(double));
    line_info.w_v = malloc(line_info.count*sizeof(double));
    line_info.my_s_v2 = malloc(line_info.count*sizeof(double));
    if (!line_info.q_v || !line_info.w_v || !line_info.my_s_v2)
      exit(fprintf(stderr,"PowderN: %s: ERROR allocating memory (init)\n", NAME_CURRENT_COMP));
    for(i=0; i<line_info.count; i++)
    {
      line_info.my_s_v2[i] = 4*PI*PI*PI*packing_factor*(L[i].DWfactor ? L[i].DWfactor : 1)
                 /(line_info.V_0*line_info.V_0*V2K*V2K)
                 *(L[i].j * L[i].F2 / L[i].q)*line_info.XsectionFactor;
      /* Is not yet divided by v^2 */
      /* Squires [3.103] */
      line_info.q_v[i] = L[i].q*K2V;
      line_info.w_v[i] = L[i].w;
    }
  }
  if (line_info.V_0) {
    /* Is not yet divided by v */
    line_info.my_a_v = packing_factor*line_info.sigma_a/line_info.V_0*2200*100;   // Factor 100 to convert from barns to fm^2
    line_info.my_inc = packing_factor*line_info.sigma_i/line_info.V_0*100;   // Factor 100 to convert from barns to fm^2

    printf("PowderN: %s: Vc=%g [Angs] sigma_abs=%g [barn] sigma_inc=%g [barn] reflections=%s\n",
      NAME_CURRENT_COMP, line_info.V_0, line_info.sigma_a, line_info.sigma_i, reflections && strlen(reflections) ? reflections : "NULL");
  }

  //printf("INTIALIZE line_info.v = %f, line_info.v_min = %f, line_info.v_max = %f, line_info.neutron_passed = %f\n",line_info.v,line_info.v_min,line_info.v_max,line_info.neutron_passed);

  Powder_storage.line_info_storage = &line_info;
  Powder_storage.vertical_angular_limit = d_phi;
  
  // Need to specify if this process is isotropic
  This_process.non_isotropic_rot_index = -1; // Yes (powder)
  //This_process.non_isotropic_rot_index =  1;  // No (single crystal)

  // The type of the process must be saved in the global enum process
  This_process.eProcess = Powder;

  // Packing the data into a structure that is transported to the main component
  This_process.data_transfer.pointer_to_a_Powder_physics_storage_struct = &Powder_storage;
  This_process.data_transfer.pointer_to_a_Powder_physics_storage_struct->my_scattering = effective_my_scattering;
  This_process.probability_for_scattering_function = &Powder_physics_my;
  This_process.scattering_function = &Powder_physics_scattering;
    
  // This will be the same for all process's, and can thus be moved to an include.
  This_process.process_p_interact = interact_fraction;
  sprintf(This_process.name,"%s",NAME_CURRENT_COMP);
  rot_copy(This_process.rotation_matrix,ROT_A_CURRENT_COMP);
  sprintf(global_process_element.name,"%s",NAME_CURRENT_COMP);
  global_process_element.component_index = INDEX_CURRENT_COMP;
  global_process_element.p_scattering_process = &This_process;

if (_getcomp_index(init) < 0) {
fprintf(stderr,"Powder_process:%s: Error identifying Union_init component, %s is not a known component name.\n",
NAME_CURRENT_COMP, init);
exit(-1);
}


struct pointer_to_global_process_list *global_process_list = COMP_GETPAR3(Union_init, init, global_process_list);
  add_element_to_process_list(global_process_list,global_process_element);
 %}

TRACE
%{
%}

FINALLY
%{
  free(line_info.list);
  free(line_info.q_v);
  free(line_info.w_v);
  free(line_info.my_s_v2);
%}

END
