/*****************************************************************************
* McStas, neutron ray-tracing package
*         Copyright (C) 1997-2008 Risoe National Laboratory, Roskilde, Denmark
*
* Component: PowderN
*
* %I
* Written by: P. Willendrup, L. Chapon, K. Lefmann, A.B.Abrahamsen, N.B.Christensen, E.M.Lauridsen.
* Date: 4.2.98
* Origin: McStas release
* Modified by: KL, KN 20.03.98   (rewrite)
* Modified by: KL,    28.09.01   (two lines)
* Modified by: KL,    22.05.03   (background)
* Modified by: KL, PW 01.05.05   (N lines)
* Modified by: PW, LC 04.10.05   (Merge with Chapon Powder_multi)
* Modified by: PW, KL 05.06.07   (Concentricity)
* Modified by: EF,    17.10.08   (added any shape sample geometry)
* Modified by: MB,    25.07.18   (fixed indexing bug in calc_xsect)
* Modified by: Jan Saroun(JS) '17(added target_index, d_omega, tth_sign)
* Modified by: EF, June 2023     (can now read CIF files)
*
* General powder sample (N lines, single scattering, incoherent scattering)
*
* %D
* General powder sample with
*         many scattering vectors
*         possibility for intrinsic line broadening
*         incoherent elastic background ratio is specified by user
*         No multiple scattering. No secondary extinction.
*
* Based on Powder1/Powder2/Single_crystal.
* Geometry is a powder filled cylinder, sphere, box or any shape from an OFF file.
* Incoherent scattering is only provided here to account for a background.
* The efficient is highly improved when restricting the vertical scattering
*   range on the Debye-Scherrer cone (with 'd_phi' and 'focus_flip').
* The unit cell volume Vc may also be computed when giving the density,
*   the atomic/molecular weight and the number of atoms per unit cell.
* A simple strain handling is available by mean of either a global Strain parameter,
*   or a column with a strain value per Bragg reflection. The strain values are
*   specified in ppm (1e-6).
* The Single_crystal component can also handle a powder mode, as well as an
*   approximated texture.
*
* <b>Sample shape:</b>
* Sample shape may be a cylinder, a sphere, a box or any other shape.
*   box/plate:       xwidth x yheight x zdepth (thickness=0)
*   hollow box/plate:xwidth x yheight x zdepth and thickness>0
*   cylinder:        radius x yheight (thickness=0)
*   hollow cylinder: radius x yheight and thickness>0
*   sphere:          radius (yheight=0 thickness=0)
*   hollow sphere:   radius and thickness>0 (yheight=0)
*   any shape:       geometry=OFF_file
*
*   The complex geometry option handles any closed non-convex polyhedra.
*   It computes the intersection points of the neutron ray with the object
*   transparently, so that it can be used like a regular sample object.
*   It supports the PLY, OFF and NOFF file format but not COFF (colored faces).
*   Such files may be generated from XYZ data using:
*   qhull < coordinates.xyz Qx Qv Tv o > geomview.off
*   or
*     powercrust coordinates.xyz
*   and viewed with geomview or java -jar jroff.jar (see below).
*   The default size of the object depends of the OFF file data, but its
*   bounding box may be resized using xwidth,yheight and zdepth.
*
* If you use this component and produce valuable scientific results, please
* cite authors with references bellow (in <a href="#links">Links</a>).
*
* Example: PowderN(reflections = "c60.lau", d_phi = 15 , radius = 0.01,
*   yheight = 0.05, Vc = 1076.89, sigma_abs = 0, delta_d_d=0, DW=1))
*
* <b>Powder definition file format</b>
* Powder structure is specified with an ascii data file 'reflections'.
* The powder data are free-text column based files.
* The reflection list should be ordered by decreasing d-spacing values.
*       ... d ... F2
* Lines begining by '#' are read as comments (ignored) but they may contain
* the following keywords (in the header):
*   #Vc           <value of unit cell volume Vc [Angs^3]>
*   #sigma_abs    <value of Absorption cross section [barns]>
*   #sigma_inc    <value of Incoherent cross section [barns]>
*   #Debye_Waller <value of Debye-Waller factor DW>
*   #delta_d_d/d    <value of delta_d_d/d width for all lines>
* These values are not read if entered as component parameters (Vc=...)
*
* The signification of the columns in the numerical block may be
* set using the 'format' parameter, by defining signification of the
* columns as a vector of indexes in the order
*   format={j,d,F2,DW,delta_d_d/d,1/2d,q,F,Strain}
*
* Signification of the symbols is given below. Indices start at 1.
* Indices with zero means that the column are not present, so that:
*   Crystallographica={ 4,5,7,0,0,0,0,0,0 }
*   Fullprof         ={ 4,0,8,0,0,5,0,0,0 }
*   Lazy             ={17,6,0,0,0,0,0,13,0}
*
* At last, the format may be overridden by direct definition of the
* column indexes in the file itself by using the following keywords
* in the header (e.g. '#column_j 4'):
*   #column_j     <index of the multiplicity 'j' column>
*   #column_d     <index of the d-spacing 'd' column [Angs]>
*   #column_F2    <index of the squared str. factor '|F|^2' column [b]>
*   #column_F     <index of the structure factor norm '|F|' column>
*   #column_DW    <index of the Debye-Waller factor 'DW' column>
*   #column_Dd    <index of the relative line width delta_d_d/d broadening 'Dd' column>
*   #column_inv2d <index of the 1/2d=sin(theta)/lambda 'inv2d' column>
*   #column_q     <index of the scattering wavevector 'q' column [Angs-1]>
*   #column_strain <index of the strain line shift Delta/d [ppm]>
*
* Last, CIF, FullProf and ShelX files can be read, and converted to F2(hkl) lists
* if 'cif2hkl' is installed. The CIF2HKL env variable can be used to point to a
* proper executable, else the McCode, then the system installed versions are used.
*
* <b>Concentricity</b>
*
* PowderN assumes 'concentric' shape, i.e. can contain other components inside its
* optional inner hollow. Example, Sample in Al cryostat:
*
*
* COMPONENT Cryo = PowderN(reflections="Al.laz", radius = 0.01, thickness = 0.001,
*                          concentric = 1, p_interact=0.1)
* AT (0,0,0) RELATIVE Somewhere
*
* COMPONENT Sample = some_other_component(with geometry FULLY enclosed in the hollow)
* AT (0,0,0) RELATIVE Somewhere
*
* COMPONENT Cryo2 = COPY(Cryo)(concentric = 0)
* AT (0,0,0) RELATIVE Somewhere
*
*
* (The second instance of the cryostat component can also be written out completely
*  using PowderN(...). In both cases, this second instance needs concentric = 0.)
* The concentric arrangment can not be used with OFF geometry specification.
*
* This sample component can advantageously benefit from the SPLIT feature, e.g.
* SPLIT COMPONENT pow = PowderN(...)
*
* %P
* INPUT PARAMETERS
* radius: [m]          Outer radius of sample in (x,z) plane
* xwidth: [m]          Horiz. dimension of sample, as a width
* yheight: [m]         Height of sample y direction
* zdepth: [m]          Depth of box sample
* thickness: [m]        Thickness of hollow sample. Negative value extends the hollow volume outside of the box/cylinder.
* reflections: [string] Input file for reflections (LAZ LAU CIF, FullProf, ShelX). Use only incoherent scattering if NULL or "" 
* d_phi: [deg]         Angle corresponding to the vertical angular range to focus to, e.g. detector height. 0 for no focusing.
* d_omega: [deg]       Horizontal focus range (only for incoherent scattering), 0 for no focusing.
* tth_sign: [1]        Sign of the scattering angle. If 0, the sign is chosen randomly (left and right). ONLY functional in combination with d_phi and ONLY applies to bragg lines.
* focus_flip:   [1]    Controls the sense of d_phi. If 0 d_phi is measured against the xz-plane. If !=0 d_phi is measured against zy-plane.
* pack: [1]            Packing factor.
* 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).
* p_inc: [1]           Fraction of incoherently scattered neutron rays.
* p_transmit: [1]      Fraction of transmitted (only attenuated) neutron rays.
* p_interact: [1]      Fraction of events interacting coherently with sample.
* concentric: [1]      Indicate that this component has a hollow geometry and may contain other components. It should then be duplicated after the inside part (only for box, cylinder, sphere).
* geometry: [str]      Name of an Object File Format (OFF) or PLY file for complex geometry. The OFF/PLY file may be generated from XYZ coordinates using qhull/powercrust.
* 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).
* sigma_abs: [barns]   Absorption cross section per unit cell at 2200 m/s. Use a negative value to inactivate it.
* sigma_inc: [barns]   Incoherent cross section per unit cell. Use a negative value to inactivate it.
* 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 incoherent scattering at, e.g. next is +1
* order: [1]           Flag that determines whether the intensity should (1) not (0) be dampened by weighting multiple scattering
*
* CALCULATED PARAMETERS:
* line_info: [struct]  internal structure containing many members/info
* line_info.type: interaction type of event 't'=Transmit, 'i'=Incoherent, 'c'=Coherent [char]
* line_info.dq:   wavevector transfer of last coherent scattering event [Angs-1]
*
* %L
* "Validation of a realistic powder sample using data from DMC at PSI" Willendrup P, Filges U, Keller L, Farhi E, Lefmann K, Physica B-Cond Matt 385 (2006) 1032.
* %L
* See also: Powder1, Single_crystal
* %L
* See <a href="http://icsd.ill.fr">ICSD</a> Inorganic Crystal Structure Database
* %L
* <a href="http://www.ncnr.nist.gov/resources/n-lengths/">Cross sections for single elements</a>
* %L
* <a href="http://www.ncnr.nist.gov/resources/sldcalc.html>Cross sections for compounds</a>
* %L
* <a href="http://www.webelements.com/">Web Elements</a>
* %L
* <a href="http://www.ill.eu/sites/fullprof/index.html">Fullprof</a> powder refinement
* %L
* <a href="http://www.crystallographica.com/">Crystallographica</a> software (free license)
* %L
* <a href="http://www.geomview.org">Geomview and Object File Format (OFF)</a>
* %L
* Java version of Geomview (display only) <a href="http://www.holmes3d.net/graphics/roffview/">jroff.jar</a>
* %L
* <a href="http://qhull.org">qhull</a>
* %L
* <a href="http://www.cs.ucdavis.edu/~amenta/powercrust.html">powercrust</a>
*
* %E
*****************************************************************************/
DEFINE COMPONENT PowderN

SETTING PARAMETERS (string reflections="NULL", string geometry="NULL",
  vector format={0, 0, 0, 0, 0, 0, 0, 0, 0},
  radius=0, yheight=0, xwidth=0, zdepth=0, thickness=0,
  pack=1, Vc=0, sigma_abs=0, sigma_inc=0, delta_d_d=0, p_inc=0.1, p_transmit=0.1,
  DW=0, nb_atoms=1, d_omega=0, d_phi=0, tth_sign=0, p_interact=0.8,
  concentric=0, density=0, weight=0, barns=1, Strain=0, focus_flip=0, int target_index=0, int order=1)


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

SHARE
%{
  /* 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
  #define POWDERN_DECL

  struct line_data {
    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 {
    struct line_data* 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;
    double sigma_i;
    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;
    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 lfree; // store mean free path for the last event;
    double *w_v, *q_v, *my_s_v2;
    double radius_i, xwidth_i, yheight_i, zdepth_i;
    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;
  };

  // PN_list_compare *****************************************************************

  int
  PN_list_compare (const void* a, const void* b) {
    const struct line_data* pa = a;
    const struct line_data* pb = b;

    /* Sort by q */
    if (pa->q < pb->q)
      return -1;
    if (pa->q > pb->q)
      return 1;

    /* In case of tie, sort by F2 also */
    if (pa->F2 < pb->F2)
      return -1;
    if (pa->F2 > pb->F2)
      return 1;

    /* In case of tie, sort by j also */
    if (pa->j < pb->j)
      return -1;
    if (pa->j > pb->j)
      return 1;

    return 0;
  } /* PN_list_compare */

  #ifndef CIF2HKL
  #define CIF2HKL
  // hkl_filename = cif2hkl(file, options)
  //   used to convert CIF/CFL/INS file into F2(hkl)
  //   the CIF2HKL env var can point to a cif2hkl executable
  //   else the McCode binary is attempted, then the system.
  char*
  cif2hkl (char* infile, char* options) {
    char cmd[1024];
    int ret = 0;
    int found = 0;
    char* OUTFILE;
    char* inpath;

    // get filename extension
    char* ext = strrchr (infile, '.');
    if (!ext || ext == infile)
      return infile;
    else
      ext++;

    // return input when no extension or not a CIF/FullProf/ShelX file
    if (strcasecmp (ext, "cif") && strcasecmp (ext, "pcr") && strcasecmp (ext, "cfl") && strcasecmp (ext, "shx") && strcasecmp (ext, "ins")
        && strcasecmp (ext, "res"))
      return infile;

    OUTFILE = malloc (1024);
    if (!OUTFILE) {
      free (OUTFILE);
      return infile;
    }
    inpath = malloc (1024);
    if (!inpath) {
      free (OUTFILE);
      free (inpath);
      return infile;
    }

    // get input file path from read-table:Open_File
    FILE* f_infile = Open_File (infile, "r", inpath);
    if (!f_infile) {
      free (OUTFILE);
      free (inpath);
      free (f_infile);
      return infile;
    }
    fclose (f_infile);

    strncpy (OUTFILE, tmpnam (NULL), 1024); // create an output temporary file name

    // try in order the CIF2HKL env var, then the system cif2hkl, then the McCode one
    if (!found && getenv ("CIF2HKL")) {
      snprintf (cmd, 1024, "%s -o %s %s %s", getenv ("CIF2HKL"), OUTFILE, options, inpath);
      ret = system (cmd);
      if (ret != -1 && ret != 127)
        found = 1;
    }
    if (!found) {
      // try with cif2hkl command from the system PATH
      snprintf (cmd, 1024, "%s -o %s %s %s", "cif2hkl", OUTFILE, options, infile);
      ret = system (cmd);
      if (ret != -1 && ret != 127)
        found = 1;
    }
    if (!found) {
      // As a last resort, attempt with cif2hkl from $MCSTAS/bin
      snprintf (cmd, 1024, "%s%c%s%c%s -o %s %s %s", getenv (FLAVOR_UPPER) ? getenv (FLAVOR_UPPER) : MCSTAS, MC_PATHSEP_C, "bin", MC_PATHSEP_C, "cif2hkl",
                OUTFILE, options, inpath);
      ret = system (cmd);
    }
    // ret = -1:  child process could not be created
    // ret = 127: shell could not be executed in the child process
    if (ret == -1 || ret == 127) {
      free (OUTFILE);
      return (NULL);
    }

    // test if the result file has been created
    FILE* file = fopen (OUTFILE, "r");
    if (!file) {
      free (OUTFILE);
      return (NULL);
    }
    MPI_MASTER (printf ("%s: INFO: Converting %s into F2(HKL) list %s\n", __FILE__, inpath, OUTFILE); printf ("%s\n", cmd););
    fflush (NULL);
    fclose (file);
    return (OUTFILE);
  } // cif2hkl
  #endif

  int
  read_line_data (char* SC_file, struct line_info_struct* info) {
    struct line_data* 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;
    char* filename = NULL;

    if (!SC_file || !strlen (SC_file) || !strcmp (SC_file, "NULL")) {
      MPI_MASTER (printf ("PowderN: %s: Using incoherent elastic scattering only.\n", info->compname););
      info->count = 0;
      return (0);
    }
    filename = cif2hkl (SC_file, "--mode NUC");
    if (filename != SC_file)
      info->flag_barns = 1;                          // cif2hkl returns barns
    long retval = Table_Read (&sTable, filename, 1); /* read 1st block data from SC_file into sTable*/
    if (retval < 0) {
      fprintf (stderr, "PowderN: Could not open file %s - exiting!\n", SC_file);
      exit (-1);
    }

    /* 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;

    MPI_MASTER (Table_Info (sTable); printf ("PowderN: %s: Reading %d rows from %s\n", info->compname, size, SC_file););

    if (filename == SC_file) { // only when not from cif2hkl
      if (info->column_order[0] == 4 && info->flag_barns != 0)
        MPI_MASTER (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)
        MPI_MASTER (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*)malloc (size * sizeof (struct line_data));

    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 && !(info->column_order[1] > 0)) // Only use if d not read already
      {
        d = Table_Index (sTable, i, info->column_order[5] - 1);
        d = (d > 0 ? 1 / d / 2 : 0);
      }
      if (info->column_order[6] > 0 && !(info->column_order[1] > 0)) // Only use if d not read already
      {
        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) {
        MPI_MASTER (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)))) {
          MPI_MASTER (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), PN_list_compare);

    MPI_MASTER (printf ("PowderN: %s: Read %i reflections from file '%s'\n", info->compname, list_count, SC_file););

    // remove temporary F2(hkl) file when giving CFL/CIF/ShelX file
    if (filename != SC_file)
      unlink (filename);

    info->list = list;
    info->count = list_count;

    return (list_count);
  } /* read_line_data */

  /* 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           */
  #pragma acc routine seq
  int
  calc_xsect (double v, double* qv, double* my_sv2, int count, double* sum, struct line_info_struct* line_info) {
    int Nq = 0, line = 0, line0 = 0;
    *sum = 0;

    /* check if a line_info element has been recorded already - not on OpenACC */
    #ifndef OPENACC
    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 */
        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++;
      } else
        line_info->xs_reuse++;
      line0 = Nq;
    }

    line_info->xs_calls++;
    #endif

    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;
    }

    return (Nq);
  } /* calc_xsect */

  #endif /* !POWDERN_DECL */
%}

DECLARE
%{
  struct line_info_struct line_info;
  double* columns;
  off_struct offdata;
  double tgt_x;
  double tgt_y;
  double tgt_z;
%}

INITIALIZE
%{
  /* We ought to clean up the columns variable as format is now a proper vector/array */
  columns = format;

  int i = 0;
  struct line_data* 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 = sigma_abs;
  line_info.sigma_i = sigma_inc;
  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.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] = (int)columns[i];
  }
  strncpy (line_info.compname, NAME_CURRENT_COMP, 256);

  line_info.shape = -1; /* -1:no shape, 0:cyl, 1:box, 2:sphere, 3:any-shape  */
  if (geometry && strlen (geometry) && strcmp (geometry, "NULL") && strcmp (geometry, "0")) {
    #ifndef USE_OFF
    fprintf (stderr, "Error: You are attempting to use an OFF geometry without -DUSE_OFF. You will need to recompile with that define set!\n");
    exit (-1);
    #else
    if (off_init (geometry, xwidth, yheight, zdepth, 0, &offdata)) {
      line_info.shape = 3;
      thickness = 0;
      concentric = 0;
    }
    #endif
  } else if (xwidth && yheight && zdepth)
    line_info.shape = 1; /* box */
  else if (radius > 0 && yheight)
    line_info.shape = 0; /* cylinder */
  else if (radius > 0 && !yheight)
    line_info.shape = 2; /* sphere */

  if (line_info.shape < 0)
    exit (fprintf (stderr,
                   "PowderN: %s: sample has invalid dimensions.\n"
                   "ERROR    Please check parameter values (xwidth, yheight, zdepth, radius).\n",
                   NAME_CURRENT_COMP));
  if (thickness) {
    if (radius && (radius < fabs (thickness))) {
      MPI_MASTER (printf ("PowderN: %s: hollow sample thickness is larger than its volume (sphere/cylinder).\n"
                          "WARNING  Please check parameter values. Using bulk sample (thickness=0).\n",
                          NAME_CURRENT_COMP););
      thickness = 0;
    } else if (!radius && (xwidth < 2 * fabs (thickness) || yheight < 2 * fabs (thickness) || zdepth < 2 * fabs (thickness))) {
      MPI_MASTER (printf ("PowderN: %s: hollow sample thickness is larger than its volume (box).\n"
                          "WARNING  Please check parameter values.\n",
                          NAME_CURRENT_COMP););
    }
  }

  if (concentric && thickness == 0) {
    MPI_MASTER (printf ("PowderN: %s:Can not use concentric mode\n"
                        "WARNING     on non hollow shape. Ignoring.\n",
                        NAME_CURRENT_COMP););
    concentric = 0;
  }

  if (thickness > 0) {
    if (radius > thickness) {
      line_info.radius_i = radius - thickness;
    } else {
      if (xwidth > 2 * thickness)
        line_info.xwidth_i = xwidth - 2 * thickness;
      if (yheight > 2 * thickness)
        line_info.yheight_i = yheight - 2 * thickness;
      if (zdepth > 2 * thickness)
        line_info.zdepth_i = zdepth - 2 * thickness;
    }
  } else if (thickness < 0) {
    thickness = fabs (thickness);
    if (radius) {
      line_info.radius_i = radius;
      radius = line_info.radius_i + thickness;
    } else {
      line_info.xwidth_i = xwidth;
      line_info.yheight_i = yheight;
      line_info.zdepth_i = zdepth;
      xwidth = xwidth + 2 * thickness;
      yheight = yheight + 2 * thickness;
      zdepth = zdepth + 2 * thickness;
    }
  }

  if (!line_info.yheight_i) {
    line_info.yheight_i = yheight;
  }

  if (!p_interact) {
    fprintf (stderr, "WARNING(%s): p_interact=0, adjusting to 0.01, to avoid algorithm instability\n", NAME_CURRENT_COMP);
    p_interact = 1e-2;
  }
  if (!p_inc) {
    fprintf (stderr, "WARNING(%s): p_inc=0, adjusting to 0.01, to avoid algorithm instability\n", NAME_CURRENT_COMP);
    p_inc = 1e-2;
  }
  if (!p_transmit) {
    fprintf (stderr, "WARNING(%s): p_transmit=0, adjusting to 0.01, to avoid algorithm instability\n", NAME_CURRENT_COMP);
    p_transmit = 1e-2;
  }
  double p_sum = p_interact + p_inc + p_transmit;
  p_interact = p_interact / p_sum;
  p_inc = p_inc / p_sum;
  p_transmit = p_transmit / p_sum;

  if (concentric) {
    MPI_MASTER (printf ("PowderN: %s: Concentric mode - remember to include the 'opposite' copy of this component !\n"
                        "WARNING  The equivalent, 'opposite' comp should have concentric=0\n",
                        NAME_CURRENT_COMP););
    if (p_transmit < 0.1) {
      MPI_MASTER (printf ("PowderN: %s: Concentric mode and p_transmit<0.1 !\n"
                          "WARNING  Consider increasing p_transmit as few particles will reach the inner hollow.\n",
                          NAME_CURRENT_COMP););
    }
  }

  if (reflections && strlen (reflections) && strcmp (reflections, "NULL") && strcmp (reflections, "0")) {
    i = read_line_data (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.sigma_a < 0)
    line_info.sigma_a = 0;
  if (line_info.sigma_i < 0)
    line_info.sigma_i = 0;

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

  if (line_info.V_0 > 0 && p_inc && !line_info.sigma_i) {
    MPI_MASTER (printf ("PowderN: %s: WARNING: You have requested statistics for incoherent scattering but not defined sigma_inc!\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 > 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 * pack * (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 > 0) {
    /* Is not yet divided by v */
    line_info.my_a_v = pack * line_info.sigma_a / line_info.V_0 * 2200 * 100; // Factor 100 to convert from barns to fm^2
    line_info.my_inc = pack * line_info.sigma_i / line_info.V_0 * 100;        // Factor 100 to convert from barns to fm^2
    MPI_MASTER (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"););
  }

  /* update JS, 1/7/2017
    Get target coordinates relative to the local reference frame.
  */
  if (target_index) {
    Coords ToTarget;
    ToTarget = coords_sub (POS_A_COMP_INDEX (INDEX_CURRENT_COMP + target_index), POS_A_CURRENT_COMP);
    ToTarget = rot_apply (ROT_A_CURRENT_COMP, ToTarget);
    coords_get (ToTarget, &tgt_x, &tgt_y, &tgt_z);
    NORM (tgt_x, tgt_y, tgt_z);
    printf ("PowderN: Target direction = (%g %g %g)\n", tgt_x, tgt_y, tgt_z);
  } else {
    tgt_x = 0.0;
    tgt_y = 0.0;
    tgt_z = 1.0;
  }
%}
TRACE
%{
  double t0, t1, t2, t3, v, v1, l_full, l, l_1, dt, alpha0, alpha, theta, my_s, my_s_n, sg;
  double solid_angle;
  double neutrontype = 0;
  double ntype = 0;
  double arg, tmp_vx, tmp_vy, tmp_vz, vout_x, vout_y, vout_z, nx, ny, nz, pmul = 1;
  int line;
  char intersect = 0;
  char intersecti = 0;

  // Variables calculated within thread for thread purpose only
  char type = '\0';
  int itype = 0;
  double d_phi_thread = d_phi;
  // These ones are injected back to struct at the end of TRACE in non-OpenACC case
  int nb_reuses = line_info.nb_reuses;
  int nb_refl = line_info.nb_refl;
  int nb_refl_count = line_info.nb_refl_count;
  double vcache = line_info.v;
  double Nq = line_info.Nq;
  double v_min = line_info.v_min;
  double v_max = line_info.v_max;
  double lfree = line_info.lfree;
  long xs_compute = line_info.xs_compute;
  long xs_reuse = line_info.xs_reuse;
  long xs_calls = line_info.xs_calls;
  double dq = line_info.dq;

  #ifdef OPENACC
  #ifdef USE_OFF
  off_struct thread_offdata = offdata;
  #endif
  #else
  #define thread_offdata offdata
  #endif

  if (line_info.V_0 > 0 && (line_info.count || line_info.my_inc)) {
    if (line_info.shape == 1) {
      intersect = box_intersect (&t0, &t3, x, y, z, vx, vy, vz, xwidth, yheight, zdepth);
      intersecti = box_intersect (&t1, &t2, x, y, z, vx, vy, vz, line_info.xwidth_i, line_info.yheight_i, line_info.zdepth_i);
    } else if (line_info.shape == 0) {
      intersect = cylinder_intersect (&t0, &t3, x, y, z, vx, vy, vz, radius, yheight);
      intersecti = cylinder_intersect (&t1, &t2, x, y, z, vx, vy, vz, line_info.radius_i, line_info.yheight_i);
    } else if (line_info.shape == 2) {
      intersect = sphere_intersect (&t0, &t3, x, y, z, vx, vy, vz, radius);
      intersecti = sphere_intersect (&t1, &t2, x, y, z, vx, vy, vz, line_info.radius_i);
    }
    #ifdef USE_OFF
    else if (line_info.shape == 3) {
      intersect = off_intersect (&t0, &t3, NULL, NULL, x, y, z, vx, vy, vz, 0, 0, 0, thread_offdata);
      intersecti = 0;
    }
    #endif
  }

  if (intersect && t3 > 0) {

    if (concentric) {
      /* Set up for concentric case */
      /* 'Remove' the backside of this comp */
      if (!intersecti) {
        t1 = (t3 + t0) / 2;
      }
      t2 = t1;
      t3 = t1;
      dt = -1.0 * rand01 (); /* In case of scattering we will scatter on 'forward' part of sample */
    } else {
      if (!intersecti) {
        t1 = (t3 + t0) / 2;
        t2 = t1;
      }
      dt = randpm1 (); /* Possibility to scatter at all points in line of sight */
    }

    /* Neutron enters at t=t0. */
    if (t0 < 0)
      t0 = 0; /* already in sample */
    if (t1 < 0)
      t1 = 0; /* already in inner hollow */
    if (t2 < 0)
      t2 = 0; /* already past inner hollow */
    v = sqrt (vx * vx + vy * vy + vz * vz);
    l_full = v * (t3 - t2 + t1 - t0);

    if (line_info.neutron_passed < CHAR_BUF_LENGTH) {
      if (v < v_min)
        v_min = v;
      if (v > v_max)
        v_max = v;
      line_info.neutron_passed++;
    }

    /* Calculate total scattering cross section at relevant velocity - but not on GPU*/
    #ifndef OPENACC
    if (fabs (v - vcache) < 1e-6) {
      nb_reuses++;
    } else {
      #endif
      Nq = calc_xsect (v, line_info.q_v, line_info.my_s_v2, line_info.count, &line_info.my_s_v2_sum, &line_info);
      vcache = v;
      nb_refl += Nq;
      nb_refl_count++;
      #ifndef OPENACC
    }
    #endif

    if (t3 < 0) {
      t3 = 0; /* Already past sample?! */
      if (line_info.flag_warning < 10)
        printf ("PowderN: %s: Warning: Neutron has already passed us? (Skipped).\n"
                "         In concentric geometry, this may be caused by a missing concentric=0 option in 2nd enclosing instance.\n",
                NAME_CURRENT_COMP);
      line_info.flag_warning++;
    } else {
      if (dt < 0) {                 /* Calculate scattering point position */
        dt = fabs (dt) * (t1 - t0); /* 'Forward' part */
      } else {
        dt = dt * (t3 - t2) + (t2 - t0); /* Possibly also 'backside' part */
      }
      if (order) {
        my_s = line_info.my_s_v2_sum / (v * v) + line_info.my_inc;
      } else {
        my_s = line_info.my_inc;
      }
      /* Total attenuation from scattering */
      lfree = 0;
      ntype = rand01 ();
      /* How to handle this one? Transmit (1) / Incoherent (2) / Coherent (3) ? */
      if (ntype < p_transmit) {
        neutrontype = 1;
        l = l_full; /* Passing through, full length */
        PROP_DT (t3);
      } else if (ntype >= p_transmit && ntype < (p_transmit + p_inc)) {
        neutrontype = 2;
        l = v * dt;        /* Penetration in sample */
        PROP_DT (dt + t0); /* Point of scattering */
        SCATTER;
      } else if (ntype >= p_transmit + p_inc) {
        neutrontype = 3;
        l = v * dt;        /* Penetration in sample */
        PROP_DT (dt + t0); /* Point of scattering */
        SCATTER;
      } else {
        exit (fprintf (stderr, "PowderN %s: DEAD - this shouldn't happen!\n", NAME_CURRENT_COMP));
      }

      if (neutrontype == 3) { /* Make coherent scattering event */
        if (line_info.count > 0) {
          /* choose line */
          if (Nq > 1)
            line = floor (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)
            ABSORB; /* No bragg scattering possible*/
          if (tth_sign == 0) {
            sg = randpm1 ();
            if (sg > 0)
              sg = 1;
            else
              sg = -1;
          } else {
            sg = tth_sign / fabs (tth_sign);
          }
          theta = asin (arg); /* Bragg scattering law */
          /* Choose point on Debye-Scherrer cone */
          if (d_phi_thread) { /* relate height of detector to the height on DS cone */
            arg = sin (d_phi_thread * DEG2RAD / 2) / sin (2 * theta);
            /* If full Debye-Scherrer cone is within d_phi, don't focus */
            if (arg < -1 || arg > 1)
              d_phi_thread = 0;
            /* Otherwise, determine alpha to rotate from scattering plane
               into d_phi focusing area*/
            else
              alpha = 2 * asin (arg);
          }
          if (d_phi_thread) {
            /* Focusing */
            alpha = fabs (alpha);
            alpha0 = 0.5 * randpm1 () * alpha;
            if (focus_flip) {
              alpha0 += M_PI_2;
            }
          } 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
           */

          /* update JS, 1/7/2017
            If a target is defined, try to define vertical axis as a normal to the plane
                defined by the incident neutron velocity and target position.
                Check that v is not ~ parallel to the target direction.
          */
          double vnorm = 0.0;
          if (target_index) {
            vec_prod (tmp_vx, tmp_vy, tmp_vz, vx, vy, vz, tgt_x, tgt_y, tgt_z);
            vnorm = sqrt (tmp_vx * tmp_vx + tmp_vy * tmp_vy + tmp_vz * tmp_vz) / v;
          }
          // no target or direction is nearly parallel to v:
          if (vnorm < 0.01) {
            if (fabs (vx / v) < fabs (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 * sg * 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;

          /* Since now scattered and new direction given, calculate path to exit */
          if (line_info.shape == 1) {
            intersect = box_intersect (&t0, &t3, x, y, z, vx, vy, vz, xwidth, yheight, zdepth);
            intersecti = box_intersect (&t1, &t2, x, y, z, vx, vy, vz, line_info.xwidth_i, line_info.yheight_i, line_info.zdepth_i);
          } else if (line_info.shape == 0) {
            intersect = cylinder_intersect (&t0, &t3, x, y, z, vx, vy, vz, radius, yheight);
            intersecti = cylinder_intersect (&t1, &t2, x, y, z, vx, vy, vz, line_info.radius_i, line_info.yheight_i);
          } else if (line_info.shape == 2) {
            intersect = sphere_intersect (&t0, &t3, x, y, z, vx, vy, vz, radius);
            intersecti = sphere_intersect (&t1, &t2, x, y, z, vx, vy, vz, line_info.radius_i);
          }
          #ifdef USE_OFF
          else if (line_info.shape == 3) {
            intersect = off_intersect (&t0, &t3, NULL, NULL, x, y, z, vx, vy, vz, 0, 0, 0, thread_offdata);
            intersecti = 0;
          }
          #endif

          if (!intersect) {
            /* Strange error: did not hit cylinder */
            if (line_info.flag_warning < 10)
              printf ("PowderN: %s: WARNING: Did not hit sample from inside (coh). ABSORB.\n", NAME_CURRENT_COMP);
            line_info.flag_warning++;
            ABSORB;
          }

          if (!intersecti) {
            t1 = (t3 + t0) / 2;
            t2 = t1;
          }

          if (concentric && intersecti) {
            /* In case of concentricity, 'remove' backward wall of sample */
            t2 = t1;
            t3 = t1;
          }

          if (t0 < 0)
            t0 = 0; /* already in sample */
          if (t1 < 0)
            t1 = 0; /* already in inner hollow */
          if (t2 < 0)
            t2 = 0; /* already past inner hollow */

          l_1 = v * (t3 - t2 + t1 - t0); /* Length to exit */

          pmul *= 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 d_phi focusing - BUT only when d_phi != 0 */
          if (d_phi_thread) {
            pmul *= alpha / PI;
            if (tth_sign)
              pmul *= 0.5;
          }

          type = 'c';
          itype = 1;
          dq = line_info.q_v[line] * V2K;
          lfree = 1 / (line_info.my_a_v / v + my_s);
        } /* else transmit <-- No powder lines in file */
      } /* Coherent scattering event */
      else if (neutrontype == 2) { /* Make incoherent scattering event */
        if (d_omega && d_phi_thread) {
          randvec_target_rect_angular (&vx, &vy, &vz, &solid_angle, tgt_x, tgt_y, tgt_z, d_omega * DEG2RAD, d_phi_thread * DEG2RAD, ROT_A_CURRENT_COMP);
        } else if (d_phi_thread) {
          randvec_target_rect_angular (&vx, &vy, &vz, &solid_angle, tgt_x, tgt_y, tgt_z, 2 * PI, d_phi_thread * DEG2RAD, ROT_A_CURRENT_COMP);
        } else {
          randvec_target_circle (&vx, &vy, &vz, &solid_angle, 0, 0, 1, 0);
        }
        v1 = sqrt (vx * vx + vy * vy + vz * vz);
        vx *= v / v1;
        vy *= v / v1;
        vz *= v / v1;

        /* Since now scattered and new direction given, calculate path to exit */
        if (line_info.shape == 1) {
          intersect = box_intersect (&t0, &t3, x, y, z, vx, vy, vz, xwidth, yheight, zdepth);
          intersecti = box_intersect (&t1, &t2, x, y, z, vx, vy, vz, line_info.xwidth_i, line_info.yheight_i, line_info.zdepth_i);
        } else if (line_info.shape == 0) {
          intersect = cylinder_intersect (&t0, &t3, x, y, z, vx, vy, vz, radius, yheight);
          intersecti = cylinder_intersect (&t1, &t2, x, y, z, vx, vy, vz, line_info.radius_i, line_info.yheight_i);
        } else if (line_info.shape == 2) {
          intersect = sphere_intersect (&t0, &t3, x, y, z, vx, vy, vz, radius);
          intersecti = sphere_intersect (&t1, &t2, x, y, z, vx, vy, vz, line_info.radius_i);
        }
        #ifdef USE_OFF
        else if (line_info.shape == 3) {
          intersect = off_intersect (&t0, &t3, NULL, NULL, x, y, z, vx, vy, vz, 0, 0, 0, thread_offdata);
          intersecti = 0;
        }
        #endif

        if (!intersect) {
          /* Strange error: did not hit cylinder */
          if (line_info.flag_warning < 10)
            printf ("PowderN: %s: WARNING: Did not hit sample from inside (inc). ABSORB.\n", NAME_CURRENT_COMP);
          line_info.flag_warning++;
          ABSORB;
        }

        if (!intersecti) {
          t1 = (t3 + t0) / 2;
          t2 = t1;
        }

        if (concentric && intersecti) {
          /* In case of concentricity, 'remove' backward wall of sample */
          t2 = t1;
          t3 = t1;
        }

        if (t0 < 0)
          t0 = 0; /* already in sample */
        if (t1 < 0)
          t1 = 0; /* already in inner hollow */
        if (t2 < 0)
          t2 = 0; /* already past inner hollow */

        l_1 = v * (t3 - t2 + t1 - t0); /* Length to exit */

        pmul *= l_full * line_info.my_inc * exp (-(line_info.my_a_v / v + my_s) * (l + l_1)) / (p_inc);
        pmul *= solid_angle / (4 * PI);
        lfree = 1 / (line_info.my_a_v / v + my_s);
        type = 'i';
        itype = 2;

      } /* Incoherent scattering event */
      else if (neutrontype == 1) {
        /* Make transmitted (absorption-corrected) event */
        /* No coordinate changes here, simply change neutron weight */
        pmul *= exp (-(line_info.my_a_v / v + my_s) * (l)) / (p_transmit);
        lfree = 1 / (line_info.my_a_v / v + my_s);
        type = 't';
        itype = 3;
      }
      p *= pmul;
    } /* Neutron leaving since it has passed already */
  } /* else transmit non interacting neutrons */

  // Inject these back to global struct in non-OpenACC case
  #ifndef OPENACC
  line_info.nb_reuses = nb_reuses;
  line_info.nb_refl = nb_refl;
  line_info.nb_refl_count = nb_refl_count;
  line_info.v = vcache;
  line_info.Nq = Nq;
  line_info.v_min = v_min;
  line_info.v_max = v_max;
  line_info.lfree = lfree;
  line_info.xs_compute = xs_compute;
  line_info.xs_reuse = xs_reuse;
  line_info.xs_calls = xs_calls;
  line_info.dq = dq;
  #endif
%}

FINALLY
%{
  free (line_info.list);
  free (line_info.q_v);
  free (line_info.w_v);
  free (line_info.my_s_v2);
  MPI_MASTER (if (line_info.flag_warning)
                  printf ("PowderN: %s: Error messages were repeated %i times with absorbed neutrons.\n", NAME_CURRENT_COMP, line_info.flag_warning);

              /* in case this instance is used in a SPLIT, we can recommend the
                 optimal iteration value */
              if (line_info.nb_refl_count) {
                double split_iterations = (double)line_info.nb_reuses / line_info.nb_refl_count + 1;
                double split_optimal = (double)line_info.nb_refl / line_info.nb_refl_count;
                if (split_optimal > split_iterations + 5)
                  printf ("PowderN: %s: Info: you may highly improve the computation efficiency by using\n"
                          "    SPLIT %i COMPONENT %s=PowderN(...)\n"
                          "  in the instrument description %s.\n",
                          NAME_CURRENT_COMP, (int)split_optimal, NAME_CURRENT_COMP, instrument_source);
              });
%}

MCDISPLAY
%{
  if (line_info.V_0) {

    if (line_info.shape == 0) { /* cyl */
      circle ("xz", 0, yheight / 2.0, 0, radius);
      circle ("xz", 0, -yheight / 2.0, 0, radius);
      line (-radius, -yheight / 2.0, 0, -radius, +yheight / 2.0, 0);
      line (+radius, -yheight / 2.0, 0, +radius, +yheight / 2.0, 0);
      line (0, -yheight / 2.0, -radius, 0, +yheight / 2.0, -radius);
      line (0, -yheight / 2.0, +radius, 0, +yheight / 2.0, +radius);
      if (thickness) {
        double radius_i = radius - thickness;
        circle ("xz", 0, yheight / 2.0, 0, radius_i);
        circle ("xz", 0, -yheight / 2.0, 0, radius_i);
        line (-radius_i, -yheight / 2.0, 0, -radius_i, +yheight / 2.0, 0);
        line (+radius_i, -yheight / 2.0, 0, +radius_i, +yheight / 2.0, 0);
        line (0, -yheight / 2.0, -radius_i, 0, +yheight / 2.0, -radius_i);
        line (0, -yheight / 2.0, +radius_i, 0, +yheight / 2.0, +radius_i);
      }
    } else if (line_info.shape == 1) { /* box */
      double xmin = -0.5 * xwidth;
      double xmax = 0.5 * xwidth;
      double ymin = -0.5 * yheight;
      double ymax = 0.5 * yheight;
      double zmin = -0.5 * zdepth;
      double zmax = 0.5 * zdepth;
      multiline (5, xmin, ymin, zmin, xmax, ymin, zmin, xmax, ymax, zmin, xmin, ymax, zmin, xmin, ymin, zmin);
      multiline (5, xmin, ymin, zmax, xmax, ymin, zmax, xmax, ymax, zmax, xmin, ymax, zmax, xmin, ymin, zmax);
      line (xmin, ymin, zmin, xmin, ymin, zmax);
      line (xmax, ymin, zmin, xmax, ymin, zmax);
      line (xmin, ymax, zmin, xmin, ymax, zmax);
      line (xmax, ymax, zmin, xmax, ymax, zmax);
      if (line_info.zdepth_i) {
        xmin = -0.5 * line_info.xwidth_i;
        xmax = 0.5 * line_info.xwidth_i;
        ymin = -0.5 * line_info.yheight_i;
        ymax = 0.5 * line_info.yheight_i;
        zmin = -0.5 * line_info.zdepth_i;
        zmax = 0.5 * line_info.zdepth_i;
        multiline (5, xmin, ymin, zmin, xmax, ymin, zmin, xmax, ymax, zmin, xmin, ymax, zmin, xmin, ymin, zmin);
        multiline (5, xmin, ymin, zmax, xmax, ymin, zmax, xmax, ymax, zmax, xmin, ymax, zmax, xmin, ymin, zmax);
        line (xmin, ymin, zmin, xmin, ymin, zmax);
        line (xmax, ymin, zmin, xmax, ymin, zmax);
        line (xmin, ymax, zmin, xmin, ymax, zmax);
        line (xmax, ymax, zmin, xmax, ymax, zmax);
      }
    }
    if (line_info.shape == 2) { /* sphere */
      if (line_info.radius_i) {
        circle ("xy", 0, 0, 0, line_info.radius_i);
        circle ("xz", 0, 0, 0, line_info.radius_i);
        circle ("yz", 0, 0, 0, line_info.radius_i);
      }
      circle ("xy", 0, 0, 0, radius);
      circle ("xz", 0, 0, 0, radius);
      circle ("yz", 0, 0, 0, radius);
    } else if (line_info.shape == 3) { /* OFF file */
      off_display (offdata);
    }
  }
%}
END