/*******************************************************************************
*
* McStas, neutron ray-tracing package
*         Copyright (C) 1997-2011, All rights reserved
*         Risoe National Laboratory, Roskilde, Denmark
*         Institut Laue Langevin, Grenoble, France
*
* %I
* Written by: Peter Willendrup, derived from TOF_lambda_monitor.comp
* Date: May 23, 2012
* Version: $Revision: 4587 $
* Origin: DTU Physics
* Release: McStas 1.12c
*
* Special "Brilliance" monitor of FIXED size 1x1cm. 
*
* %D
* If used in the right setting, will output "instantaneous" and "mean" brilliances in units of Neutrons/cm^2/ster/AA/s. Conditions for proper units:
* <ul>
* <li>Use a with a source of area 1x1cm
* <li>The source must illuminate/focus to an area of 1x1cm a 1m distance
* <li>Parametrise the Brilliance_monitor with the frequency of the source
* <li>To not change the source TOF distribution, place the Brilliance monitor close to the source!
* </ul>
* 
* with a source of area 1x1cm illuminating/focusing to an area of 1x1cm a 1m distance, this monitor will output "instantaneous" and "mean" brilliances in units of Neutrons/cm^2/ster/AA/s
* 
* Here is an example of the use of the component. Note how the mentioned Unit conditions are implemented in instrument code.
*
*COMPONENT Source = ESS_moderator_long(
*    l_low = lambdamin, l_high = lambdamax, dist = 1, xw = 0.01, yh = 0.01,
*    freq = 14, T=50, tau=287e-6, tau1=0, tau2=20e-6,
*    n=20, n2=5, d=0.00286, chi2=0.9, I0=6.9e11, I2=27.6e10,
*    branch1=0, branch2=0.5, twopulses=0, size=0.01)
*  AT (0, 0, 0) RELATIVE Origin
*
*COMPONENT BRIL = Brilliance_monitor(nlam=196,nt=401,filename="bril.sim",
*	t_0=0,t_1=4000,lambda_0=lambdamin,
*	lambda_1=lambdamax, Freq=14)
*AT (0,0,0.000001) RELATIVE Source
*
* %P
* INPUT PARAMETERS:
*
* nlam:      Number of bins in wavelength (1)
* nt:        Number of bins in TOF (1)
* t_0:       Minimum time (us)
* t_1:       Maximum time (us)
* lambda_0:  Minimum wavelength detected (AA)
* lambda_1:  Maximum wavelength detected (AA)
* filename:  Defines filenames for the detector images. Stored as:<br>Peak_&lt;filename&gt; and Mean_&lt;filename&gt; (string)
* restore_neutron: If set, the monitor does not influence the neutron state (1)
* Freq:      Source frequency. Use freq=1 for reactor source (Hz)
* srcarea:   Source area (cm^2)
* tofcuts:   Flag to generate TOF-distributions as function of wavelength (1)
* toflambda: Flag to generate TOF-lambda distribution output ´ (1)
* 
* OUTPUT PARAMETERS:
*
* Div_N:    Array of neutron counts
* Div_p:    Array of neutron weight counts
* Div_p2:   Array of second moments
*
* %E
*******************************************************************************/
DEFINE COMPONENT Brilliance_monitor
DEFINITION PARAMETERS (nlam=101, nt=1001, string filename, t_0=0, t_1=20000, srcarea=1)
  SETTING PARAMETERS (lambda_0=0, lambda_1=20, restore_neutron=0, Freq, int tofcuts=0, int toflambda=0)
  OUTPUT PARAMETERS (tt_0, tt_1, BRIL_N, BRIL_p, BRIL_p2, BRIL_mean, BRIL_peak, BRIL_meanN, BRIL_peakN, BRIL_meanE, BRIL_peakE)
// STATE PARAMETERS (x,y,z,vx,vy,vz,t,s1,s2,p)
// POLARISATION PARAMETERS (sx,sy,sz)
DECLARE
  %{
    double BRIL_N[nt][nlam];
    double BRIL_p[nt][nlam];
    double BRIL_p2[nt][nlam];
    double BRIL_mean[nlam];
    double BRIL_meanN[nlam];
    double BRIL_meanE[nlam];
    double BRIL_peak[nlam];
    double BRIL_peakN[nlam];
    double BRIL_peakE[nlam];

    double BRIL_shape[nt];
    double BRIL_shapeN[nt];
    double BRIL_shapeE[nt];

    double tt_0, tt_1;
    double xmin=-0.005, xmax=0.005, ymin=-0.005, ymax=0.005;
    double ster=1e-4;
    double prsec=1e-6;
    double dlam;
    double dt;
  %}
INITIALIZE
  %{
    int i,j;

    tt_0 = t_0*prsec;
    tt_1 = t_1*prsec;
    dt=(t_1-t_0)*prsec/nt;
    dlam=(lambda_1-lambda_0)/(nlam-1);
    for (i=0; i<nlam; i++)
      {
	BRIL_mean[i] = 0;
	BRIL_peak[i] = 0;
	BRIL_meanN[i] = 0;
	BRIL_peakN[i] = 0;
	BRIL_meanE[i] = 0;
	BRIL_peakE[i] = 0;
	for (j=0; j<nt; j++)
	  {
	    BRIL_N[j][i] = 0;
	    BRIL_p[j][i] = 0;
	    BRIL_p2[j][i] = 0;
	    if (i==0) {
	      BRIL_shape[j] = 0;
	      BRIL_shapeN[j] = 0;
	      BRIL_shapeE[j] = 0;
	    }
	  }
      }
  %}
TRACE
  %{
    int i,j;
    double div;
    double lambda;
    double Pnorm;

    PROP_Z0;
    lambda = (2*PI/V2K)/sqrt(vx*vx + vy*vy + vz*vz);
    if (x>xmin && x<xmax && y>ymin && y<ymax &&
        lambda > lambda_0 && lambda < lambda_1)
    {
      if (t < tt_1 && t > tt_0)
      {
        i = floor((lambda - lambda_0)*nlam/(lambda_1 - lambda_0));
        j = floor((t-tt_0)*nt/(tt_1-tt_0));
	Pnorm=p/dlam/ster/srcarea;
	BRIL_meanN[i]++;
	BRIL_mean[i] += Pnorm;
	BRIL_meanE[i] += Pnorm*Pnorm;
	Pnorm=Pnorm/Freq/dt;
	BRIL_N[j][i]++;
        BRIL_p[j][i] += Pnorm;
        BRIL_p2[j][i] += Pnorm*Pnorm;
	
      }
    } 
    if (restore_neutron) {
      RESTORE_NEUTRON(INDEX_CURRENT_COMP, x, y, z, vx, vy, vz, t, sx, sy, sz, p);
    }  
  %}
SAVE
  %{
  /* First, dump the 2D monitor */
  
  /* For each Wavelength channel, find peak brilliance */
  int i,j,jmax;
  double Pnorm;
  char ff[256];
  char tt[256];
  
  for (i=0; i<nlam; i++)
    {
      Pnorm = -1;
      jmax = -1;
      for (j=0; j<nt; j++)
	{
	  if (BRIL_p[j][i]>=Pnorm)
	    {
	      Pnorm = BRIL_p[j][i];
	      jmax=j;
	    }
	  BRIL_shape[j] = BRIL_p[j][i];
	  BRIL_shapeN[j] = BRIL_N[j][i];
	  BRIL_shapeE[j] = BRIL_p2[j][i];
	  
	}
      if (tofcuts == 1) {
	sprintf(ff, "Shape_%s_%g",filename,lambda_0+i*dlam);
	sprintf(tt, "Peak shape at %g AA",lambda_0+i*dlam);
	DETECTOR_OUT_1D(
			tt,
			"TOF [us]",
			"Peak Brilliance",
			"Shape", t_0, t_1, nt,
			&BRIL_shapeN[0],&BRIL_shape[0],&BRIL_shapeE[0],
			ff);
      }
      BRIL_peakN[i] = BRIL_N[jmax][i];
      BRIL_peak[i] = BRIL_p[jmax][i];
      BRIL_peakE[i] = BRIL_p2[jmax][i];
    }
  sprintf(ff, "Mean_%s",filename);
  DETECTOR_OUT_1D(
	"Mean brilliance",
        "Wavelength [AA]",
        "Mean Brilliance",
        "Mean", lambda_0, lambda_1, nlam,
        &BRIL_meanN[0],&BRIL_mean[0],&BRIL_meanE[0],
        ff);
  sprintf(ff, "Peak_%s",filename);
  DETECTOR_OUT_1D(
	"Peak brilliance",
        "Wavelength [AA]",
        "Peak Brilliance",
        "Peak", lambda_0, lambda_1, nlam,
        &BRIL_peakN[0],&BRIL_peak[0],&BRIL_peakE[0],
        ff);

  /* MPI related NOTE: Order is important here! The 2D-data used to generate wavelength-slices and calculate
     the peak brilliance should be done LAST, otherwise we will get a factor of MPI_node_count too much as 
     scatter/gather has been performed on the arrays... */
  if (toflambda == 1) {
    sprintf(ff, "TOFL_%s",filename);
    DETECTOR_OUT_2D(
		    "TOF-wavelength brilliance",
		    "Time-of-flight [\\gms]", "Wavelength [AA]",
		    t_0, t_1, lambda_0, lambda_1,
		    nt, nlam,
		    &BRIL_N[0][0],&BRIL_p[0][0],&BRIL_p2[0][0],
		    filename);
  }
  %}

MCDISPLAY
  %{
    
    multiline(5, (double)xmin, (double)ymin, 0.0,
                 (double)xmax, (double)ymin, 0.0,
                 (double)xmax, (double)ymax, 0.0,
                 (double)xmin, (double)ymax, 0.0,
                 (double)xmin, (double)ymin, 0.0);
%}

END


