photrans Namespace Reference

This slightly less simple photon transport uses a template for photon collection in time and in distance along the fiber. More...

Classes
class	BrightnessLevel
class	FiberBrightness
class	ImprovedTransport
	a class for transporting photons in a roughly realistic way More...
class	PhotonSystRewriter
class	PhotonTransport
	a class for transporting photons in a roughly realistic way More...
struct	RateInfo
	a struct to hold collection rate info More...

Functions
static double	line_efficiency (TH2D *themap, const double Xa, const double Ya, const double Xb, const double Yb)
void	load_hset (TFile *f, const char *name, const char *humanname, std::vector< TH2D * > &hold, const bool verbose)

Detailed Description

This slightly less simple photon transport uses a template for photon collection in time and in distance along the fiber.

This slightly less simple photon transport doesn't propagate individual photons (thus "simple"), but the model is gaining some realism.

Author

auris.nosp@m.ano@.nosp@m.fnal..nosp@m.gov transport simulation

rbpat.nosp@m.ter@.nosp@m.calte.nosp@m.ch.e.nosp@m.du

Function Documentation

static double photrans::line_efficiency ( TH2D *  themap, const double  Xa, const double  Ya, const double  Xb, const double  Yb  )

static

Definition at line 429 of file ImprovedTransport_module.cc.

References ana::binx, ana::biny, ana::binz, om::cerr, dx, dy, nd_projection_maker::eff, cet::hypot(), std::max(), fillBadChanDBTables::step, sum, submit_syst::x, and submit_syst::y.

Referenced by photrans::ImprovedTransport::GetPosCorr().

  {
    double sum = 0, dem = 0;

    // This is a dumb method which just takes little steps across and finds
    // the average, but the performance is fine, so we'll go with it.
    const double stepsize = 0.01; // cm

    const double dy = Yb - Ya;
    const double dx = Xb - Xa;
    const double seglen = hypot(dx, dy);
    const int nstep = std::max(1, int(seglen/stepsize));
    const double thisstepsize = seglen/nstep;
    const double thisstepstart = thisstepsize/2;

    for(int step = 0; step < nstep; step++){
      const double s = thisstepstart + step*thisstepsize;
      const double sfrac = seglen == 0? 0: s/seglen;

      // Flip the x coordinate here because of an artifact in how I generated
      // the efficiency maps.  It only matters for horizontals where we want
      // the fibers to be at the bottom (and air to be at the top).  Local +x
      // is global -y, where fibers should fall, but I generated the maps the
      // other way around.
      const double x = -(Xa + sfrac*dx);

      const double y = Ya + sfrac*dy;

      double eff = themap->GetBinContent(themap->FindBin(x, y));

      // There are some zero bins in the corners since the bins are square and
      // were evaluated at the bin centers.  Use any non-zero adjacent bin in
      // this case.
      int binx = 0, biny = 0;
      if(eff <= 0){
        int binz = 0;
        themap->GetBinXYZ(themap->FindBin(x, y), binx, biny, binz);
        eff = themap->GetBinContent(binx+1, biny);
      }
      if(eff <= 0) eff = themap->GetBinContent(binx-1, biny);
      if(eff <= 0) eff = themap->GetBinContent(binx, biny+1);
      if(eff <= 0) eff = themap->GetBinContent(binx, biny-1);

      if(eff <= 0) std::cerr << "GetPosCorr should not happen: " << eff
          << " efficiency with " << themap->GetName()
          << " point " << -x << " " << y
          << " from path " << Xa << " " << Ya << " " << Xb << " " << Yb
          << " length " << seglen << "\n";

      // Handle the case of zero step size, even though in all cases I've seen,
      // these particles also have zero energy, so it doesn't matter.
      sum += thisstepsize == 0? eff: thisstepsize*eff;
      dem += thisstepsize;
    }

    // If the length is zero, return the single efficiency stored in "sum".  If
    // somehow denominator is zero, prevent a NaN, but that shouldn't happen.
    return seglen == 0? sum: dem == 0? 0: sum/dem;
  }

void photrans::load_hset	(	TFile *	f,
		const char *	name,
		const char *	humanname,
		std::vector< TH2D * > &	hold,
		const bool	verbose
	)

Definition at line 491 of file ImprovedTransport_module.cc.

References om::cout, make_syst_table_plots::h, and getGoodRuns4SAM::n.

Referenced by photrans::ImprovedTransport::LoadPosCorrHists().

  {
    for(int n = 1; ; n++){
      TH2D * h = dynamic_cast<TH2D *>(f->Get(Form("%s_%d", name, n)));
      if(h == NULL) break;
      h->SetDirectory(NULL);
      hold.push_back(h);
    }

    if(verbose) std::cout << "ImprovedTransport: using "
                          << hold.size() << " " << humanname << "\n";

    if(hold.empty())
      throw cet::exception("NoPosCorrHists")
        << "ImprovedTransport: No " << humanname << "\n";
  }