/*******************************************************************************
*
* McStas, neutron ray-tracing package
*         Copyright 1997-2002, All rights reserved
*         Risoe National Laboratory, Roskilde, Denmark
*         Institut Laue Langevin, Grenoble, France
*
* Component: Virtual_input
*
* %I
* Written by: <a href="mailto:farhi@ill.fr">E. Farhi</a>
* Date: Sep 28th, 2001
* Origin: <a href="http://www.ill.fr">ILL</a>
* Modified by: EF, Oct 2002. make use of shared read-table library.
*
* Source-like component that generates neutron events from an ascii
* 'virtual source' filename.
*
* %D
*   This component reads neutron events stored from a file, and sends them into
* the instrument. It thus replaces a Source component, using a previously
* computed neutron set. The 'source' file type is an ascii text file with the
* format listed below. The number of neutron events for the
* simulation is set to the length of the 'source' file times the
* repetition parameter 'repeat_count' (1 by default).
*   It is particularly useful to generate a virtual source at a point that few
* neutron reach. A long simulation will then only be performed once, to create
* the 'source' filename. Further simulations are much faster if they start from
* this low flux position with the 'source' filename.
*
* The input file format is:
* text column formatted with lines containing 11 values in the order:
*       p x y z vx vy vz t sx sy sz stored into about 83 bytes/n.
*
* %BUGS
* We recommend NOT to use parallel execution (MPI) with this component. If you
* need to, set parameter 'smooth=1'.
*
* EXAMPLE:
* To create a 'source' file collecting all neutron states, use:
*   COMPONENT MySourceCreator = Virtual_output(filename = "MySource.list")
* at the position where will be the Virtual_input.
* Then unactivate the part of the simulation description before (and including)
* the component MySourceCreator. Put the new instrument source:
*   COMPONENT Source = Virtual_input(filename="MySource.list")
* at the same position as 'MySourceCreator'.
* A Vitess filename may be obtained from the 'Vitess_output' component or from a
* Vitess simulation (104 bytes per neutron) and read with Vitess_input.
*
* %P
* INPUT PARAMETERS
* filename: [str]    Name of the neutron input file. Empty string "" unactivates component 
*
* Optional input parameters
* repeat_count: [1]  Number of times the source must be generated/repeated 
* verbose: [0/1]     Display additional information about source, recommended 
* smooth: [0/1]      Smooth sparsed event files for filename repetitions. Use this option with MPI. This will apply gaussian distributions around initial events from the file 
*
* %E
*******************************************************************************/

DEFINE COMPONENT Virtual_input

SETTING PARAMETERS (string filename=0, verbose=0,repeat_count=1,smooth=1)

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

SHARE
%{
%include "read_table-lib"

long Virtual_input_Read_Input(char *aFile, t_Table *aTable, long *aOffset)
  {
    long max_lines = 50000;
    long length=0;

    if (!aFile) return (0);

    Table_Free(aTable);

    /* Open neutron input text filename. */
    Table_Read_Offset(aTable, aFile, 0, aOffset, max_lines);  /* read data from filename into rTable */

    return(aTable->rows);
  }
%}

DECLARE
%{
  int repeat_number;      /* Neutron repeat of the filename */
  int repeat_cnt;         /* Repeat count, MPI taken into account */
  long pos;               /* current pos in block */
  long nrows;             /* total nrows in block */
  long Offset;            /* offset in filename */
  double filename_ncount; /* total number of neutrons in filename */
  double n_neutrons;
  char read_block;        /* flag to start by reading block */
  char first_block;
  char end_reading;
  t_Table rTable;

  /* statistics on first block */
  double mean_x;
  double mean_y;
  double mean_z;
  double mean_vx;
  double mean_vy;
  double mean_vz;
  double mean_dx;
  double mean_dy;
  double mean_dz;
  double min_x; 
  double min_y;
  double min_z;
  double max_x;
  double max_y;
  double max_z;
  double min_vx;
  double min_vy; 
  double min_vz;
  double max_vx;
  double max_vy;
  double max_vz;
  double n_count_extrapolated;
%}

INITIALIZE
%{
  repeat_number=1;
  pos=0;
  nrows=0;
  Offset=0;
  filename_ncount=0;
  n_neutrons=0;
  read_block=1;
  first_block=1;
  end_reading=0;
  mean_x=0;
  mean_y=0;
  mean_z=0;
  mean_vx=0;
  mean_vy=0;
  mean_vz=0;
  mean_dx=0;
  mean_dy=0;
  mean_dz=0;
  min_x=FLT_MAX;
  min_y=FLT_MAX;
  min_z=FLT_MAX;
  max_x=-FLT_MAX;
  max_y=-FLT_MAX;
  max_z=-FLT_MAX;
  min_vx=FLT_MAX;
  min_vy=FLT_MAX;
  min_vz=FLT_MAX;
  max_vx=-FLT_MAX;
  max_vy=-FLT_MAX;
  max_vz=-FLT_MAX;
  n_count_extrapolated=0;

  Table_Init(&rTable, 0, 0);

  if (!filename || !repeat_count)
  {
    fprintf(stderr,"Virtual_input: %s: please give me a filename name (filename) to read (repeat_count>0).\n", NAME_CURRENT_COMP);
    exit(-1);
  }

  if (filename && strlen(filename) && strcmp(filename, "NULL") && strcmp(filename,"0") && repeat_count>0) {

    if (verbose)
      printf("Virtual_input: %s: Reading neutron events from filename '%s'. Repeat %g time(s)\n", NAME_CURRENT_COMP, filename, repeat_count);

#if defined (USE_MPI)
    if (!smooth && mpi_node_count > 1) {
      if (verbose)
      printf("Virtual_input: %s: smoothing (smooth=1) is recommended when running MPI execution\n", NAME_CURRENT_COMP);
    }
#endif

    double min_dv=fabs(max_vx-min_vx);
    if (min_dv > fabs(max_vy-min_vy)) min_dv = fabs(max_vy-min_vy);
    if (min_dv > fabs(max_vz-min_vz)) min_dv = fabs(max_vz-min_vz);
    min_vx = min_dv;

    if (verbose && smooth)
        printf("* Beam will be smoothed\n");
  } else if (!filename)
    exit(fprintf(stderr,"Virtual_input: %s: please give me a filename name (filename).\n", NAME_CURRENT_COMP));

  repeat_cnt = repeat_count;
#if defined (USE_MPI)
  repeat_cnt = ceil(1.0*repeat_cnt/mpi_node_count);
#endif
%}

TRACE
%{
  if (filename && strlen(filename) && strcmp(filename, "NULL") && strcmp(filename,"0")) {
    while (read_block && !end_reading) {
      /* read block and increase Offset for next reading */
      nrows = Virtual_input_Read_Input(filename, &rTable, &Offset);
      if (!nrows) { /* nrows is 0 if end of filename/no filename */
        if (!filename_ncount) {
          filename_ncount = (double)mcget_run_num();  /* ncount in filename */
          if (verbose)
            printf("Virtual_input: %s: filename '%s' contains %g events\n", NAME_CURRENT_COMP, filename, filename_ncount);
          /* set ncount from filename length */
          mcset_ncount(filename_ncount*repeat_cnt);
        }
        Offset = 0;       /* reposition to begining of filename */
        repeat_number++;  /* we start a new repeat_cnt loop */

        /* end of simulation if ... */
        if (repeat_number > repeat_cnt) {
          if (verbose)
            printf("Virtual_input: %s: Ending after %g events (%li repeat count)\n", NAME_CURRENT_COMP, (double)mcget_run_num(), (long)repeat_cnt);
          read_block=0; mcset_ncount(mcget_run_num()); pos=0;
          end_reading = 1;
        }
        /* else continue reading blocks */

      } else { /* block at Offset could be read */
        pos = 0;  /* position at begining of new block */
        read_block = 0;
      }
    }

      /* &p, &x, &y, &z, &vx, &vy, &vz, &t, &sx, &sy, &sz */
    if (!end_reading) {
      double *dptr = &rTable.data[11*pos];
      p  =  *dptr++;
      x  =  *dptr++;
      y  =  *dptr++;
      z =  *dptr++;
      vx =  *dptr++;
      vy =  *dptr++;
      vz  =  *dptr++;
      t =  *dptr++;
      sx =  *dptr++;
      sy =  *dptr++;
      sz  =  *dptr;

      if (first_block) {
        double v;
        mean_x  += p*x;  mean_y  += p*y;  mean_z  += p*z;
        mean_vx += p*vx; mean_vy += p*vy; mean_vz += p*vz;
        v = sqrt(vx*vx+vy*vy+vz*vz);
        if (v)
          { mean_dx += p*fabs(vx/v); mean_dy += p*fabs(vy/v); mean_dz += p*fabs(vz/v); }
        if (x  < min_x)  min_x  = x;
        if (y  < min_y)  min_y  = y;
        if (z  < min_z)  min_z  = z;
        if (vx < min_vx) min_vx = vx;
        if (vy < min_vy) min_vy = vy;
        if (vz < min_vz) min_vz = z;
        if (x  > max_x)  max_x  = x;
        if (y  > max_y)  max_y  = y;
        if (z  > max_z)  max_z  = z;
        if (vx > max_vx) max_vx = vx;
        if (vy > max_vy) max_vy = vy;
        if (vz > max_vz) max_vz = z;
        n_neutrons += p;
      }

      pos++;
      p /= repeat_cnt;
#ifdef USE_MPI
      /* We always repeat by the number of nodes in an MPI run */
      p /= mpi_node_count;
#endif

      SCATTER;

      if (pos >= nrows) { /* reached end of block */
        read_block = 1;
        if (first_block) {
          double mean_v;
          /* display statitics for 1st block */
          mean_x  /= n_neutrons;
          mean_y  /= n_neutrons;
          mean_z  /= n_neutrons;
          mean_vx /= n_neutrons;
          mean_vy /= n_neutrons;
          mean_vz /= n_neutrons;
          mean_dx /= n_neutrons;
          mean_dy /= n_neutrons;
          mean_dz /= n_neutrons;
          /* now estimates total ncount */
          mean_v = sqrt(mean_vx*mean_vx+mean_vy*mean_vy+mean_vz*mean_vz);
          n_count_extrapolated = (double)nrows*rTable.filesize/Offset;
          if (verbose) {
            double mean_k, mean_w=0, mean_L=0;

            mean_k = V2K*mean_v;
            if (mean_k) mean_L = 2*PI/mean_k;
            mean_w = VS2E*mean_v*mean_v;
            printf("McStas Virtual Source filename %s\nContains about %g events, intensity=%g\n", filename, n_count_extrapolated, n_neutrons*rTable.filesize/Offset);

            printf("  Source size (full width in [m]):      ");
            printf("    dX=%g dY=%g dZ=%g\n", max_x-min_x, max_y-min_y, max_z-min_z);
            printf("  Source center (in [m]):               ");
            printf("    X0=%g Y0=%g Z0=%g\n", mean_x, mean_y, mean_z);
            printf("  Beam divergence (full width in [deg]):");
            printf("    dVx=%g dVy=%g dVz=%g\n",
              atan(mean_dx)*RAD2DEG,
              atan(mean_dy)*RAD2DEG,
              atan(mean_dz)*RAD2DEG);
            printf("  Beam speed (in [m/s]):                ");
            printf("    Vx=%g Vy=%g Vz=%g\n", mean_vx, mean_vy, mean_vz);
            printf("  Beam mean energy:\n");
            printf("    speed=%g [m/s] energy=%g [meV]\n    wavelength=%g [Angs] wavevector=%g [Angs-1]\n", mean_v, mean_w, mean_L, mean_k);
          }
          /* set ncount from estimate with security margin 10 % */
          mcset_ncount(n_count_extrapolated*repeat_cnt*1.1);
        }
        first_block= 0;
      }
  #if defined (USE_MPI)
      if (smooth && n_count_extrapolated)
  #else
      if (smooth && repeat_number>1 && n_count_extrapolated)
  #endif
      {
        /* apply smmothing */
        x += randnorm()*(max_x-min_x)/n_count_extrapolated/2;
        y += randnorm()*(max_y-min_y)/n_count_extrapolated/2;
        z += randnorm()*(max_z-min_z)/n_count_extrapolated/2;
        vx += randnorm()*min_vx/n_count_extrapolated/2;
        vy += randnorm()*min_vx/n_count_extrapolated/2;
        vx += randnorm()*min_vx/n_count_extrapolated/2;
      }
    } else { ABSORB; }
  }
%}

FINALLY
%{
  Table_Free(&rTable);
  if (!filename_ncount) {
    printf("Warning: Virtual_input: %s: filename '%s' was not used entirely.\n"
           "               Intensities may be wrong. Increase ncount value\n",
           NAME_CURRENT_COMP, filename);
  } else {
    double tmp;
    tmp = (double)mcget_ncount()/filename_ncount;
    if (fabs(rint(tmp)/tmp-1) > 0.02)
      printf("Warning: Virtual_input: %s: simulation finished in the middle of filename '%s'\n"
             "               ncount=%g but filename contains %g events\n"
             "               Intensities may be wrong.\n"
             "               Increase ncount value to %g or higher.\n",
	     NAME_CURRENT_COMP, filename, (double)mcget_ncount(), filename_ncount, filename_ncount*repeat_cnt);
    if (mcget_ncount() < filename_ncount*repeat_cnt)
      printf("Warning: Virtual_input: %s: not all source %s repetitions were generated.\n"
             "               Intensities may be wrong.\n"
             "               Increase ncount value to %g or higher.\n",
             NAME_CURRENT_COMP, filename, filename_ncount*repeat_cnt);
  }
%}

MCDISPLAY
%{
  if (verbose) {
    box(mean_x, mean_y, mean_z, max_x-min_x, max_y-min_y, max_z-min_z,0, 0, 1, 0);
    /* a line in the main beam direction */
    line(mean_x, mean_y, mean_z,mean_dx,mean_dy,mean_dz);
  }
%}

END
