/*******************************************************************************
*
* McStas, neutron ray-tracing package
*         Copyright 1997-2002, All rights reserved
*         Risoe National Laboratory, Roskilde, Denmark
*         Institut Laue Langevin, Grenoble, France
*
* Component: Monitor_nD_noacc
*
* %Identification
* Written by: <a href="mailto:farhi@ill.fr">Emmanuel Farhi</a>
* Date: 14th Feb 2000.
* Origin: <a href="http://www.ill.fr">ILL</a>
* Release: McStas 1.6
* Version: $Revision$
* Modified by: EF, 29th Feb 2000 : added more options, monitor shape, theta, phi
* Modified by: EF, 01st Feb 2001 : PreMonitor for correlation studies (0.13.6)
* Modified by: EF, 5th  Apr 2001 : use global functions (0.14) compile faster
* Modified by: EF, 23th Jul 2001 : log of signal, init arrays to 0, box (0.15)
* Modified by: EF, 04th Sep 2001 : log/abs of variables (0.16)
* Modified by: EF, 24th Oct 2001 : capture flux  [p*lambda/1.7985] (0.16.3)
* Modified by: EF, 27th Aug 2002 : monitor a variable in place of I (0.16.5)
* Modified by: EF, 25th Oct 2002 : banana, and auto for each variable (0.16.5)
*
* This component is a general Monitor that can output 0/1/2D signals
* (Intensity or signal vs. [something] and vs. [something] ...)
*
* %Description
* This component is a general Monitor that can output 0/1/2D signals
* It can produce many 1D signals (one for any variable specified in
* option list), or a single 2D output (two variables correlation).
* Also, an additional 'list' of neutron events can be produced.
* By default, monitor is square (in x/y plane). A disk shape is also possible
* The 'cylinder' and 'banana' option will change that for a banana shape
* The 'sphere' option simulates spherical detector. The 'box' is a box.
* The cylinder, sphere and banana should be centered on the scattering point.
* The monitored flux may be per monitor unit area, and weighted by
* a lambda/lambda(2200m/s) factor to obtain standard integrated capture flux.
* In normal configuration, the Monitor_nD measures the current parameters
* of the neutron that is beeing detected. But a PreMonitor_nD component can
* be used in order to study correlations between a neutron being detected in
* a Monitor_nD place, and given parameters that are monitored elsewhere
* (at <b>PreMonitor_nD</b>).
* The monitor can also act as a 3He gas detector, taking into account the
* detection efficiency.
*
* The 'bins' and 'limits' modifiers are to be used after each variable,
* and 'auto','log' and 'abs' come before it. (eg: auto abs log hdiv bins=10
* limits=[-5 5]) When placed after all variables,  these two latter modifiers
* apply to the signal (e.g. intensity). Unknown keywords are ignored.
* If no limits are specified for a given observable, reasonable defaults will be
* applied. Note that these implicit limits are <b>even</b> applied in list mode. 
*
* <b>Implicit limits for typical variables:</b>
* (consult monitor_nd-lib.c if you don't find your variable here)
* x, y, z: Derived from detection-object geometry
* k: [0 10] Angs-1
* v: [0 1e6] m/s
* t: [0 1] s
* p: [0 FLT_MAX] in intensity-units
* vx, vy: [-1000 1000] m/s
* vz: [0 10000] m/s
* kx, ky: [-1 1] Angs-1
* kz: [-10 10] Angs-1
* energy, omega: [0 100] meV
* lambda,wavelength: [0 100] Angs
* sx, sy, sz: [-1 1] in polarisation-units
* angle: [-50 50] deg
* divergence, vdiv, hdiv, xdiv, ydiv: [-5 5] deg
* longitude, lattitude: [-180 180] deg
* neutron: [0 simulaton_ncount]
* id, pixel id: [0 FLT_MAX]
* uservars u1,u2,u3: [-1e10 1e10]
*
* In the case of multiple components at the same position, the 'parallel'
* keyword must be used in each instance instead of defining a GROUP.
*
* <b>Possible options are</b>
* Variables to record:
*     kx ky kz k wavevector [Angs-1] Wavevector on x,y,z and norm
*     vx vy vz v            [m/s]    Velocity on x,y,z and norm
*     x y z radius          [m]      Distance, Position and norm
*     xy, yz, xz            [m]      Radial position in xy, yz and xz plane
*     kxy kyz kxz           [Angs-1] Radial wavevector in xy, yz and xz plane
*     vxy vyz vxz           [m/s]    Radial velocity in xy, yz and xz plane
*     t time                [s]      Time of Flight
*     energy omega          [meV]    energy of neutron
*     lambda wavelength     [Angs]   wavelength of neutron
*     sx sy sz              [1]      Spin
*     vdiv ydiv dy          [deg]    vertical divergence (y)
*     hdiv divergence xdiv  [deg]    horizontal divergence (x)
*     angle                 [deg]    divergence from <z> direction
*     theta longitude       [deg]    longitude (x/z) for sphere and cylinder
*     phi   lattitude       [deg]    lattitude (y/z) for sphere and cylinder
*
*     user user1            will monitor the [Mon_Name]_Vars.UserVariable{1|2|3}
*     user2 user3           to be assigned in an other component (see below)
*
*     p intensity flux      [n/s  or  n/cm^2/s]
*     ncounts n neutron     [1]      neutron ID, i.e current event index
*     pixel id              [1]      pixelID in histogram made of preceeding vars, e.g. 'theta y'. To set an offset PixelID use the 'min=value' keyword. Sets event mode.
*
* <b>Other options keywords are:</b>
*     abs                       Will monitor the abs of the following variable or of the signal (if used after all variables)
*     auto                      Automatically set detector limits for one/all
*     all  {limits|bins|auto}   To set all limits or bins values or auto mode
*     binary {float|double}     with 'source' option, saves in compact files
*     bins=[bins=20]            Number of bins in the detector along dimension
*     borders                   To also count off-limits neutrons (X < min or X > max)
*     capture                   weight by lambda/lambda(2200m/s) capture flux
*     file=string               Detector image file name. default is component name, plus date and variable extension.
*     incoming                  Monitor incoming beam in non flat det
*     limits=[min max]          Lower/Upper limits for axes (see up for the variable unit)
*     list=[counts=1000] or all For a long file of neutron characteristics with [counts] or all events
*     log                       Will monitor the log of the following variable or of the signal (if used after all variables)
*     min=[min_value]           Same as limits, but only sets the min or max
*     max=[max_value]
*     multiple                  Create multiple independant 1D monitors files
*     no or not                 Revert next option
*     outgoing                  Monitor outgoing beam (default)
*     parallel                  Use this option when the next component is at the same position (parallel components)
*     per cm2                   Intensity will be per cm^2 (detector area). Displays beam section.
*     per steradian             Displays beam solid angle in steradian
*     premonitor                Will monitor neutron parameters stored previously with <b>PreMonitor_nD</b>.
*     signal=[var]              Will monitor [var] instead of usual intensity
*     slit or absorb            Absorb neutrons that are out detector
*     source                    The monitor will save neutron states
*     unactivate                To unactivate detector (0D detector)
*     verbose                   To display additional informations
*     3He_pressure=[3 in bars]  The 3He gas pressure in detector. 3He_pressure=0 is perfect detector (default)
*
* Detector shape options (specified as xwidth,yheight,zdepth or x/y/z/min/max)
*     box                       Box of size xwidth, yheight, zdepth.
*     cylinder                  To get a cylindrical monitor (diameter is xwidth or set radius, height is yheight).
*     banana                    Same as cylinder, without top/bottom, on restricted angular area; use theta variable with limits to define arc. (diameter is xwidth or set radius, height is yheight).
*     disk                      Disk flat xy monitor. diameter is xwidth.
*     sphere                    To get a spherical monitor (e.g. a 4PI) (diameter is xwidth or set radius).
*     square                    Square flat xy monitor (xwidth, yheight).
*     previous                  The monitor uses PREVIOUS component as detector surface. Or use 'geometry' parameter to specify any PLY/OFF geometry file.
*
* <b>EXAMPLES:</b>
* <ul>
* <li>MyMon = Monitor_nD(xwidth = 0.1, yheight = 0.1, zdepth = 0,
* &emsp;&emsp;options = "intensity per cm2 angle,limits=[-5 5] bins=10,with
* &emsp;&emsp;borders, file = mon1");
*                  will monitor neutron angle from [z] axis, between -5
*                  and 5 degrees, in 10 bins, into "mon1.A" output 1D file
*
*  <li> options = "sphere theta phi outgoing"  
*       for a sphere PSD detector (out beam)  and saves into file "MyMon_[Date_ID].th_ph"
*
*  <li> options = "banana, theta limits=[10,130], bins=120, y" 
*       a theta/height banana detector
*
*  <li> options = "angle radius all auto" 
*       is a 2D monitor with automatic limits
*
*  <li> options = "list=1000 kx ky kz energy" 
*       records 1000 neutron event in a file
*
*  <li> options = "multiple kx ky kz, auto abs log t, and list all neutrons"
*        makes 4 output 1D files and produces a complete list for all neutrons
*        and monitor log(abs(tof)) within automatic limits (for t)
*
*  <li> options = "theta y, sphere, pixel min=100"
*        a 4pi detector which outputs an event list with pixelID from the actual
*        detector surface, starting from index 100.
*
* </ul>
* To dynamically define a number of bins, or limits:
*   Use in DECLARE:    char op[256];
*   Use in INITIALIZE: sprintf(op, "lambda limits=[%g %g], bins=%i", lmin, lmax, lbin);
*   Use in TRACE:      Monitor_nD(... options=op ...)
*
* <b>How to monitor any instrument/component variable into a Monitor_nD</b>
* Suppose you want to monitor a variable 'age' which you assign somwhere in
* the instrument:
*      COMPONENT MyMonitor = Monitor_nD(
*       xwidth = 0.1, yheight = 0.1,
*       user1="age", username1="Age of the Captain [years]",
*       options="user1, auto")
*      AT ...
*
* See also the example in <a href="PreMonitor_nD.html">PreMonitor_nD</a> to
* monitor neutron parameters cross-correlations.
*
* %BUGS
* The 'auto' option for guessing optimal variable bounds should NOT be used with MPI
* as each process may use different limits.
*
* %Parameters
* INPUT PARAMETERS:
*
* xwidth: [m]            Width of detector.
* yheight: [m]           Height of detector.
* zdepth: [m]            Thickness of detector (z).
* radius: [m]            Radius of sphere/banana shape monitor
* options: [str]         String that specifies the configuration of the monitor. The general syntax is "[x] options..." (see <b>Descr.</b>).
*
* Optional input parameters (override xwidth yheight zdepth):
* xmin: [m]              Lower x bound of opening
* xmax: [m]              Upper x bound of opening
* ymin: [m]              Lower y bound of opening
* ymax: [m]              Upper y bound of opening
* zmin: [m]              Lower z bound of opening
* zmax: [m]              Upper z bound of opening
* filename: [str]        Output file name (overrides file=XX option).
* bins: [1]              Number of bins to force for all variables. Use 'bins' keyword in 'options' for heterogeneous bins
* min: [u]               Minimum range value to force for all variables. Use 'min' or 'limits' keyword in 'options' for other limits
* max: [u]               Maximum range value to force for all variables. Use 'max' or 'limits' keyword in 'options' for other limits
* user1: [str]           Variable name of USERVAR to be monitored by user1.
* user2: [str]           Variable name of USERVAR to be monitored by user2.
* user3: [str]           Variable name of USERVAR to be monitored by user3.
* username1: [str]       Name assigned to User1
* username2: [str]       Name assigned to User2
* username3: [str]       Name assigned to User3
* restore_neutron: [0|1] If set, the monitor does not influence the neutron state. Equivalent to setting the 'parallel' option.
* geometry: [str]        Name of an OFF file to specify a complex geometry detector
* nowritefile: [1]      If set, monitor will skip writing to disk
*
* OUTPUT PARAMETERS:
*
* DEFS: [struct]         structure containing Monitor_nD Defines
* Vars: [struct]         structure containing Monitor_nD variables
*
* %Link
* <a href="PreMonitor_nD.html">PreMonitor_nD</a>
*
* %End
******************************************************************************/
DEFINE COMPONENT Monitor_nD_noacc
DEFINITION PARAMETERS ()
SETTING PARAMETERS (
  string user1="", string user2="", string user3="",
  xwidth=0, yheight=0, zdepth=0,
  xmin=0, xmax=0, ymin=0, ymax=0, zmin=0, zmax=0,
  int bins=0, min=-1e40, max=1e40, int restore_neutron=0, radius=0,
  string options="NULL", string filename="NULL",string geometry="NULL", int nowritefile=0,
  string username1="NULL", string username2="NULL", string username3="NULL"
)
/* these are protected C variables */
OUTPUT PARAMETERS ()
/* Neutron parameters: (x,y,z,vx,vy,vz,t,sx,sy,sz,p) */
NOACC

SHARE
%{
  %include "monitor_nd_noacc-lib"
  %include "read_table-lib"
  %include "interoff-lib"
%}

DECLARE
%{
  Monitornd_noaccDefines_type DEFS;
  Monitornd_noaccVariables_type Vars;
  MCDETECTOR detector;
  off_struct offdata;
%}

INITIALIZE
%{
  char tmp[CHAR_BUF_LENGTH];
  strcpy(Vars.compcurname, NAME_CURRENT_COMP);
  if (options != NULL)
    strncpy(Vars.option, options, CHAR_BUF_LENGTH);
  else {
    strcpy(Vars.option, "x y");
    printf("Monitor_nD: %s has no option specified. Setting to PSD ('x y') monitor.\n", NAME_CURRENT_COMP);
  }
  Vars.compcurpos = POS_A_CURRENT_COMP;

  if (strstr(Vars.option, "source"))
    strcat(Vars.option, " list, x y z vx vy vz t sx sy sz ");

  if (bins) { sprintf(tmp, " all bins=%ld ", (long)bins); strcat(Vars.option, tmp); }
  if (min > -FLT_MAX && max < FLT_MAX) { sprintf(tmp, " all limits=[%g %g]", min, max); strcat(Vars.option, tmp); }
  else if (min > -FLT_MAX) { sprintf(tmp, " all min=%g", min); strcat(Vars.option, tmp); }
  else if (max <  FLT_MAX) { sprintf(tmp, " all max=%g", max); strcat(Vars.option, tmp); }

  /* transfer, "zero", and check username- and user variable strings to Vars struct*/
  strncpy(Vars.UserName1,
    username1 && strlen(username1) && strcmp(username1, "0") && strcmp(username1, "NULL") ?
    username1 : "", 128);
  strncpy(Vars.UserName2,
    username2 && strlen(username2) && strcmp(username2, "0") && strcmp(username2, "NULL") ?
    username2 : "", 128);
  strncpy(Vars.UserName3,
    username3 && strlen(username3) && strcmp(username3, "0") && strcmp(username3, "NULL") ?
    username3 : "", 128);
  if(user1 && strlen(user1) && strcmp(user1, "0") && strcmp(user1, "NULL")){
    strncpy(Vars.UserVariable1,user1,128);
    int fail;_class_particle testparticle;
    particle_getvar(&testparticle,Vars.UserVariable1,&fail);
    if(fail){
      fprintf(stderr,"Warning (%s): user1=%s is unknown. The signal will not be resolved - this is likely not what you intended.\n",NAME_CURRENT_COMP,user1);
    }
  }
  if(user2 && strlen(user2) && strcmp(user2, "0") && strcmp(user2, "NULL")){
    strncpy(Vars.UserVariable2,user2,128);
    int fail;_class_particle testparticle;
    particle_getvar(&testparticle,Vars.UserVariable2,&fail);
    if(fail){
      fprintf(stderr,"Warning (%s): user2=%s is unknown. The signal will not be resolved - this is likely not what you intended.\n",NAME_CURRENT_COMP,user2);
    }
  }
  if(user3 && strlen(user3) && strcmp(user3, "0") && strcmp(user3, "NULL")){
    strncpy(Vars.UserVariable3,user3,128);
    int fail;_class_particle testparticle;
    particle_getvar(&testparticle,Vars.UserVariable3,&fail);
    if(fail){
      fprintf(stderr,"Warning (%s): user3=%s is unknown. The signal will not be resolved - this is likely not what you intended.\n",NAME_CURRENT_COMP,user3);
    }
  }
 
  /*sanitize parameters set for curved shapes*/
  if(strstr(Vars.option,"cylinder") || strstr(Vars.option,"banana") || strstr(Vars.option,"sphere")){
    /*this _is_ an explicit curved shape. Should have a radius. Inherit from xwidth or zdepth (diameters), x has precedence.*/
    if (!radius){
      if(xwidth){
	radius=xwidth/2.0;
      }else{
	radius=zdepth/2.0;
      }
    }else{
      xwidth=2*radius;
    }
    if(!yheight){
      /*if not set - use the diameter as height for the curved object. This will likely only happen for spheres*/
      yheight=2*radius;
    }
  }else if (radius) {
    /*radius is set - this must be a curved shape. Infer shape from yheight, and set remaining values
     (xwidth etc. They are used inside monitor_nd-lib.*/
    xwidth = zdepth = 2*radius;
    if (yheight){
      /*a height is given (and no shape explitly set - assume cylinder*/
      strcat(Vars.option, " banana");
    }else {
      strcat(Vars.option, " sphere");
      yheight=2*radius;
    }
  }

  int offflag=0;
  if (geometry && strlen(geometry) && strcmp(geometry,"0") && strcmp(geometry, "NULL")) {
    #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, 1, &offdata )) {
      printf("Monitor_nD: %s could not initiate the OFF geometry %s. \n"
             "            Defaulting to normal Monitor dimensions.\n",
             NAME_CURRENT_COMP, geometry);
      strcpy(geometry, "");
    } else {
      offflag=1;
    }
    #endif
  }

  if (!radius && !xwidth && !yheight && !zdepth && !xmin && !xmax && !ymin && !ymax &&
    !strstr(Vars.option, "previous") && (!geometry || !strlen(geometry)))
    exit(printf("Monitor_nD: %s has no dimension specified. Aborting (radius, xwidth, yheight, zdepth, previous, geometry).\n", NAME_CURRENT_COMP));

  Monitor_nd_noaccInit(&DEFS, &Vars, xwidth, yheight, zdepth, xmin,xmax,ymin,ymax,zmin,zmax,offflag);

  if (Vars.Flag_OFF) {
    offdata.mantidflag=Vars.Flag_mantid;
    offdata.mantidoffset=Vars.Coord_Min[Vars.Coord_Number-1];
  }


  if (filename && strlen(filename) && strcmp(filename,"NULL") && strcmp(filename,"0"))
    strncpy(Vars.Mon_File, filename, 128);

  /* check if user given filename with ext will be used more than once */
  if ( ((Vars.Flag_Multiple && Vars.Coord_Number > 1) || Vars.Flag_List) && strchr(Vars.Mon_File,'.') )
  { char *XY; XY = strrchr(Vars.Mon_File,'.'); *XY='_'; }

  if (restore_neutron) Vars.Flag_parallel=1;
  detector.m = 0;

#ifdef USE_MPI
MPI_MASTER(
  if (strstr(Vars.option, "auto") && mpi_node_count > 1)
    printf("Monitor_nD: %s is using automatic limits option 'auto' together with MPI.\n"
           "WARNING     this may create incorrect distributions (but integrated flux will be right).\n", NAME_CURRENT_COMP);
);
#endif

%}

TRACE
%{
  #ifdef OPENACC
  #define OPENACC_BAK
  #undef OPENACC
  #undef printf
  #undef sprintf
  #undef exit
  #endif
  
  double  transmit_he3=1.0;
  double  multiplier_capture=1.0;
  double  t0 = 0;
  double  t1 = 0;
  int     pp;
  int     intersect   = 0;
  char    Flag_Restore = 0;

  #define thread_offdata offdata
  
  /* this is done automatically
    STORE_NEUTRON(INDEX_CURRENT_COMP, x, y, z, vx, vy, vz, t, sx, sy, sz, p);
  */
  if (geometry && strlen(geometry) && strcmp(geometry,"0") && strcmp(geometry, "NULL"))
  {
    /* determine intersections with object */
    intersect = off_intersect_all(&t0, &t1, NULL, NULL,
				  x,y,z, vx, vy, vz, 0, 0, 0, &thread_offdata );
    if (Vars.Flag_mantid) {
      if(intersect) {
        Vars.OFF_polyidx=thread_offdata.nextintersect;
      } else {
        Vars.OFF_polyidx=-1;
      }
    }
  }
  else
    if ( (abs(Vars.Flag_Shape) == DEFS.SHAPE_SQUARE)
            || (abs(Vars.Flag_Shape) == DEFS.SHAPE_DISK) ) /* square xy or disk xy */
  {
    // propagate to xy plane and find intersection
    // make sure the event is recoverable afterwards
    t0 = t;
    ALLOW_BACKPROP;
    PROP_Z0;
    if ( (t>=t0) && (z==0.0) ) // forward propagation to xy plane was successful
    {
      if (abs(Vars.Flag_Shape) == DEFS.SHAPE_SQUARE)
      {
        // square xy
        intersect = (x>=Vars.mxmin && x<=Vars.mxmax && y>=Vars.mymin && y<=Vars.mymax);
      }
      else
      {
        // disk xy
        intersect = (SQR(x) + SQR(y)) <= SQR(Vars.Sphere_Radius);
      }
    }
    else
    {
      intersect=0;
    }
  }
  else if (abs(Vars.Flag_Shape) == DEFS.SHAPE_SPHERE) /* sphere */
  {
    intersect = sphere_intersect(&t0, &t1, x, y, z, vx, vy, vz, Vars.Sphere_Radius);
  /*      intersect = (intersect && t0 > 0); */
  }
  else if ((abs(Vars.Flag_Shape) == DEFS.SHAPE_CYLIND) || (abs(Vars.Flag_Shape) == DEFS.SHAPE_BANANA)) /* cylinder */
  {
    intersect = cylinder_intersect(&t0, &t1, x, y, z, vx, vy, vz, Vars.Sphere_Radius, Vars.Cylinder_Height);
  }
  else if (abs(Vars.Flag_Shape) == DEFS.SHAPE_BOX) /* box */
  {
    intersect = box_intersect(&t0, &t1, x, y, z, vx, vy, vz,
                              fabs(Vars.mxmax-Vars.mxmin), fabs(Vars.mymax-Vars.mymin), fabs(Vars.mzmax-Vars.mzmin));
  }
  else if (abs(Vars.Flag_Shape) == DEFS.SHAPE_PREVIOUS) /* previous comp */
  { intersect = 1; }

  if (intersect)
  {
    if ((abs(Vars.Flag_Shape) == DEFS.SHAPE_SPHERE) || (abs(Vars.Flag_Shape) == DEFS.SHAPE_CYLIND)
     || (abs(Vars.Flag_Shape) == DEFS.SHAPE_BOX) || (abs(Vars.Flag_Shape) == DEFS.SHAPE_BANANA)
     || (geometry && strlen(geometry) && strcmp(geometry,"0") && strcmp(geometry, "NULL")) )
    {
      /* check if we have to remove the top/bottom with BANANA shape */
        if (abs(Vars.Flag_Shape) == DEFS.SHAPE_BANANA) {
            if (intersect == 1) { // Entered and left through sides
                if (t0 < 0 && t1 > 0) {
                    t0 = t;  /* neutron was already inside ! */
                }
                if (t1 < 0 && t0 > 0) { /* neutron exit before entering !! */
                    t1 = t;
                }
                /* t0 is now time of incoming intersection with the detection area */
                if ((Vars.Flag_Shape < 0) && (t1 > 0)) {
                    PROP_DT(t1); /* t1 outgoing beam */
                } else {
                    PROP_DT(t0); /* t0 incoming beam */
                }
            } else if (intersect == 3 || intersect == 5) { // Entered from top or bottom, left through side
                if ((Vars.Flag_Shape < 0) && (t1 > 0)) {
                    PROP_DT(t1); /* t1 outgoing beam */
                } else {
                    intersect=0;
                    Flag_Restore=1;
                }
            } else if (intersect == 9 || intersect == 17) { // Entered through side, left from top or bottom
                if ((Vars.Flag_Shape < 0) && (t1 > 0)) {
                    intersect=0;
                    Flag_Restore=1;
                } else {
                    PROP_DT(t0); /* t0 incoming beam */
                }
            } else if (intersect == 13 || intersect == 19) { // Went through top/bottom on entry and exit
                intersect=0;
                Flag_Restore=1;
            } else {
                printf("Cylinder_intersect returned unexpected value %i\n", intersect);
            }
        } else {
            // All other shapes than the BANANA 
            if (t0 < 0 && t1 > 0)
              t0 = t;  /* neutron was already inside ! */
            if (t1 < 0 && t0 > 0) /* neutron exit before entering !! */
              t1 = t;
            /* t0 is now time of incoming intersection with the detection area */
            if ((Vars.Flag_Shape < 0) && (t1 > 0))
              PROP_DT(t1); /* t1 outgoing beam */
            else
              PROP_DT(t0); /* t0 incoming beam */
        }
      
      /* Final test if we are on lid / bottom of banana/sphere */
      if (abs(Vars.Flag_Shape) == DEFS.SHAPE_BANANA || abs(Vars.Flag_Shape) == DEFS.SHAPE_SPHERE) {
        if (Vars.Cylinder_Height && fabs(y) >= Vars.Cylinder_Height/2 - FLT_EPSILON) {
          intersect=0;
          Flag_Restore=1;
        }
      }
    }
  }

  if (intersect)
  {
    /* Now get the data to monitor: current or keep from PreMonitor */
/*    if (Vars.Flag_UsePreMonitor != 1)*/
/*    {*/
/*      Vars.cp  = p;*/
/*      Vars.cx  = x;*/
/*      Vars.cvx = vx;*/
/*      Vars.csx = sx;*/
/*      Vars.cy  = y;*/
/*      Vars.cvy = vy;*/
/*      Vars.csy = sy;*/
/*      Vars.cz  = z;*/
/*      Vars.cvz = vz;*/
/*      Vars.csz = sz;*/
/*      Vars.ct  = t;*/
/*    }*/

    if ((Vars.He3_pressure > 0) && (t1 != t0) && ((abs(Vars.Flag_Shape) == DEFS.SHAPE_SPHERE) || (abs(Vars.Flag_Shape) == DEFS.SHAPE_CYLIND) || (abs(Vars.Flag_Shape) == DEFS.SHAPE_BOX)))
    {
      transmit_he3 = exp(-7.417*Vars.He3_pressure*fabs(t1-t0)*2*PI*K2V);
      /* will monitor the absorbed part */
      p = p * (1-transmit_he3);
    }

    if (Vars.Flag_capture)
    {
      multiplier_capture = V2K*sqrt(vx*vx+vy*vy+vz*vz);
      if (multiplier_capture != 0) multiplier_capture = 2*PI/multiplier_capture; /* lambda. lambda(2200 m/2) = 1.7985 Angs  */
      p = p * multiplier_capture/1.7985;
    }

    pp = Monitor_nd_noaccTrace(&DEFS, &Vars, _particle);
    if (pp==0.0)
    {
      ABSORB;
    }
    else if(pp==1)
    {
      SCATTER;
    }

    /*set weight to undetected part if capture and/or he3_pressure*/
    if (Vars.He3_pressure > 0){
      /* after monitor, only remains 1-p_detect */
      p = p * transmit_he3/(1.0-transmit_he3);
    }

    if (Vars.Flag_capture){
      p = p / multiplier_capture*1.7985;
    }

    if (Vars.Flag_parallel) /* back to neutron state before detection */
      Flag_Restore = 1;
  } /* end if intersection */
  else {
    if (Vars.Flag_Absorb && !Vars.Flag_parallel)
    {
      // restore neutron ray before absorbing for correct mcdisplay
      RESTORE_NEUTRON(INDEX_CURRENT_COMP, x, y, z, vx, vy, vz, t, sx, sy, sz, p);
      ABSORB;
    }
    else Flag_Restore = 1;  /* no intersection, back to previous state */
  }

  if (Flag_Restore)
  {
    RESTORE_NEUTRON(INDEX_CURRENT_COMP, x, y, z, vx, vy, vz, t, sx, sy, sz, p);
  }
  
  #ifdef OPENACC_BAK
  #define OPENACC
  #define fprintf(stderr,...) printf(__VA_ARGS__)
  #define sprintf(string,...) printf(__VA_ARGS__)
  #define printf(...) noprintf()
  #define exit(...) noprintf()
  #endif
%}

SAVE
%{
if (!nowritefile) {
  
  /* save results, but do not free pointers */
  detector = Monitor_nd_noaccSave(&DEFS, &Vars);
}
%}

FINALLY
%{
  /* free pointers */
  Monitor_nd_noaccFinally(&DEFS, &Vars);
%}

MCDISPLAY
%{
  if (geometry && strlen(geometry) && strcmp(geometry,"0") && strcmp(geometry, "NULL"))
  {
    off_display(offdata);
  } else {
    Monitor_nd_noaccMcDisplay(&DEFS, &Vars);
  }
%}

END
