Coding conventions

[u/mrichter/AliRoot.git] / MUON / AliMUONResponseV0.cxx

/**************************************************************************
 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
 *                                                                        *
 * Author: The ALICE Off-line Project.                                    *
 * Contributors are mentioned in the code where appropriate.              *
 *                                                                        *
 * Permission to use, copy, modify and distribute this software and its   *
 * documentation strictly for non-commercial purposes is hereby granted   *
 * without fee, provided that the above copyright notice appears in all   *
 * copies and that both the copyright notice and this permission notice   *
 * appear in the supporting documentation. The authors make no claims     *
 * about the suitability of this software for any purpose. It is          *
 * provided "as is" without express or implied warranty.                  *
 **************************************************************************/

/* $Id$ */

// --------------------------
// Class AliMUONResponseV0
// --------------------------
// Implementation of Mathieson response
// ...

#include "AliMUONResponseV0.h"

#include "AliLog.h"
#include "AliMUON.h"
#include "AliMUONConstants.h"
#include "AliMUONDigit.h"
#include "AliMUONGeometrySegmentation.h"
#include "AliMUONGeometryTransformer.h"
#include "AliMUONHit.h"
#include "AliMUONSegmentation.h"
#include "AliMpArea.h"
#include "AliMpDEManager.h"
#include "AliMpVPadIterator.h"
#include "AliMpVSegmentation.h"
#include "AliRun.h"
#include "Riostream.h"
#include "TVector2.h"
#include <TMath.h>
#include <TRandom.h>

ClassImp(AliMUONResponseV0)
	
AliMUON* muon()
{
    return static_cast<AliMUON*>(gAlice->GetModule("MUON"));
}

void Global2Local(Int_t detElemId, Double_t xg, Double_t yg, Double_t zg,
                  Double_t& xl, Double_t& yl, Double_t& zl)
{  
  // ideally should be : 
  // Double_t x,y,z;
  // AliMUONGeometry::Global2Local(detElemId,xg,yg,zg,x,y,z);
  // but while waiting for this geometry singleton, let's go through
  // AliMUON still.
  
  const AliMUONGeometryTransformer* transformer = muon()->GetGeometryTransformer();
  transformer->Global2Local(detElemId,xg,yg,zg,xl,yl,zl);
}

AliMUONSegmentation* Segmentation()
{
  static AliMUONSegmentation* segmentation = muon()->GetSegmentation();
  return segmentation;
}

//__________________________________________________________________________
AliMUONResponseV0::AliMUONResponseV0()
  : AliMUONResponse(),
  fChargeSlope(0.0),
  fChargeSpreadX(0.0),
  fChargeSpreadY(0.0),
  fSigmaIntegration(0.0),
  fMaxAdc(0),
  fZeroSuppression(0),
  fChargeCorrel(0.0),
  fMathieson(new AliMUONMathieson),
  fChargeThreshold(1e-4)
{
    // Normal constructor
    AliDebug(1,Form("Default ctor"));
}

   //_________________________________________________________________________
AliMUONResponseV0::AliMUONResponseV0(const AliMUONResponseV0& rhs)
 : AliMUONResponse(rhs)
{
// Protected copy constructor

  AliFatal("Not implemented.");
}

   //__________________________________________________________________________
AliMUONResponseV0::~AliMUONResponseV0()
{
  AliDebug(1,"");
  delete fMathieson;
}

   //________________________________________________________________________
AliMUONResponseV0& AliMUONResponseV0::operator = (const AliMUONResponseV0& rhs)
{
// Protected assignement operator

  if (this == &rhs) return *this;

  AliFatal("Not implemented.");
    
  return *this;  
}

//______________________________________________________________________________
void
AliMUONResponseV0::Print(Option_t*) const
{
// Printing

  cout << " ChargeSlope=" << fChargeSlope
    << " ChargeSpreadX,Y=" << fChargeSpreadX
    << fChargeSpreadY
    << " ChargeCorrelation=" << fChargeCorrel
    << endl;
  
//Float_t fChargeSlope;              // Slope of the charge distribution
//Float_t fChargeSpreadX;            // Width of the charge distribution in x
//Float_t fChargeSpreadY;            // Width of the charge distribution in y
//Float_t fSigmaIntegration;         // Number of sigma's used for charge distribution
//Int_t   fMaxAdc;                   // Maximum ADC channel
//Int_t   fSaturation;               // Pad saturation in ADC channel
//Int_t   fZeroSuppression;          // Zero suppression threshold
//Float_t fChargeCorrel;             // amplitude of charge correlation on 2 cathods
//                                   // is RMS of ln(q1/q2)
//AliMUONMathieson* fMathieson;      // pointer to mathieson fct
//Float_t fChargeThreshold;          // Charges below this threshold are = 0  
//

}

  //__________________________________________________________________________
void AliMUONResponseV0::SetSqrtKx3AndDeriveKx2Kx4(Float_t SqrtKx3)
{
  // Set to "SqrtKx3" the Mathieson parameter K3 ("fSqrtKx3")
  // in the X direction, perpendicular to the wires,
  // and derive the Mathieson parameters K2 ("fKx2") and K4 ("fKx4")
  // in the same direction
  fMathieson->SetSqrtKx3AndDeriveKx2Kx4(SqrtKx3);
}
	
  //__________________________________________________________________________
void AliMUONResponseV0::SetSqrtKy3AndDeriveKy2Ky4(Float_t SqrtKy3)
{
  // Set to "SqrtKy3" the Mathieson parameter K3 ("fSqrtKy3")
  // in the Y direction, along the wires,
  // and derive the Mathieson parameters K2 ("fKy2") and K4 ("fKy4")
  // in the same direction
  fMathieson->SetSqrtKy3AndDeriveKy2Ky4(SqrtKy3);
}
  //__________________________________________________________________________
Float_t AliMUONResponseV0::IntPH(Float_t eloss)
{
  // Calculate charge from given ionization energy loss
  Int_t nel;
  nel= Int_t(eloss*1.e9/27.4);
  Float_t charge=0;
  if (nel == 0) nel=1;
  for (Int_t i=1;i<=nel;i++) {
      Float_t arg=0.;
      while(!arg) arg = gRandom->Rndm();
      charge -= fChargeSlope*TMath::Log(arg);    
  }
  return charge;
}

  //-------------------------------------------
Float_t AliMUONResponseV0::IntXY(Int_t idDE, AliMUONGeometrySegmentation* segmentation)
{
 // Calculate charge on current pad according to Mathieson distribution

  return fMathieson->IntXY(idDE, segmentation);
}


  //-------------------------------------------
Int_t  AliMUONResponseV0::DigitResponse(Int_t digit, AliMUONTransientDigit* /*where*/)
{
  // \deprecated method
  // Now part of the digitizer (where it belongs really), e.g. DigitizerV3
  //
  // add white noise and do zero-suppression and signal truncation

  //     Float_t meanNoise = gRandom->Gaus(1, 0.2);
    // correct noise for slat chambers;
    // one more field to add to AliMUONResponseV0 to allow different noises ????
//    Float_t meanNoise = gRandom->Gaus(1., 0.2);
//    Float_t noise     = gRandom->Gaus(0., meanNoise);
    Float_t noise     = gRandom->Gaus(0., 1.0);
    digit += TMath::Nint(noise); 
    if ( digit <= ZeroSuppression()) digit = 0;
    // if ( digit >  MaxAdc())          digit=MaxAdc();
    if ( digit >  Saturation())          
    {
      digit=Saturation();
    }

    return digit;
}

//_____________________________________________________________________________
Float_t
AliMUONResponseV0::GetAnod(Float_t x) const
{
  //
  // Return wire coordinate closest to x.
  //
  Int_t n = Int_t(x/Pitch());
  Float_t wire = (x>0) ? n+0.5 : n-0.5;
  return Pitch()*wire;
}

//______________________________________________________________________________
void 
AliMUONResponseV0::DisIntegrate(const AliMUONHit& hit, TList& digits)
{
  //
  // Go from 1 hit to a list of digits.
  // The energy deposition of that hit is first converted into charge
  // (in IntPH() method), and then this charge is dispatched on several
  // pads, according to the Mathieson distribution.
  //
  
  digits.Clear();
  
  Int_t detElemId = hit.DetElemId();
  
  // Width of the integration area
  Double_t dx = SigmaIntegration()*ChargeSpreadX();
  Double_t dy = SigmaIntegration()*ChargeSpreadY();
  
  // Use that (dx,dy) to specify the area upon which
  // we will iterate to spread charge into.
  Double_t x,y,z;
  Global2Local(detElemId,hit.X(),hit.Y(),hit.Z(),x,y,z);
  x = GetAnod(x);
  TVector2 hitPosition(x,y);
  AliMpArea area(hitPosition,TVector2(dx,dy));
  
  // Get pulse height from energy loss.
  Float_t qtot = IntPH(hit.Eloss());
  
  // Get the charge correlation between cathodes.
  Float_t currentCorrel = TMath::Exp(gRandom->Gaus(0.0,ChargeCorrel()/2.0));

  for ( Int_t cath = 0; cath < 2; ++cath )
  {
    Float_t qcath = qtot * ( cath == 0 ? currentCorrel : 1.0/currentCorrel);
    
    // Get an iterator to loop over pads, within the given area.
    const AliMpVSegmentation* seg = 
        Segmentation()->GetMpSegmentation(detElemId,cath);
      
    AliMpVPadIterator* it = seg->CreateIterator(area);
      
    if (!it)
    {
      AliError(Form("Could not get iterator for detElemId %d",detElemId));
      return;
    }
    
    // Start loop over pads.
    it->First();
    
    if ( it->IsDone() )
    {
      // Exceptional case : iterator is built, but is invalid from the start.
      AliMpPad pad = seg->PadByPosition(area.Position(),kFALSE);
      if ( pad.IsValid() )
      {
        AliWarning(Form("Got an invalid iterator bug (area.Position() is within "
                      " DE but the iterator is void) for detElemId %d cath %d",
                      detElemId,cath));        
      }
      else
      {
        AliError(Form("Got an invalid iterator bug for detElemId %d cath %d."
                      "Might be a bad hit ? area.Position()=(%e,%e) "
                      "Dimensions()=(%e,%e)",
                      detElemId,cath,area.Position().X(),area.Position().Y(),
                      area.Dimensions().X(),area.Dimensions().Y()));
      }
      delete it;
      return;
    }
    
    while ( !it->IsDone() )
    {
      // For each pad given by the iterator, compute the charge of that
      // pad, according to the Mathieson distribution.
      AliMpPad pad = it->CurrentItem();      
      TVector2 lowerLeft(hitPosition-pad.Position()-pad.Dimensions());
      TVector2 upperRight(lowerLeft + pad.Dimensions()*2.0);
      Float_t qp = TMath::Abs(fMathieson->IntXY(lowerLeft.X(),lowerLeft.Y(),
                                                upperRight.X(),upperRight.Y()));
            
      Int_t icharge = Int_t(qp*qcath);
      
      if ( qp > fChargeThreshold )
      {
        // If we're above threshold, then we create a digit,
        // and fill it with relevant information, including electronics.
        AliMUONDigit* d = new AliMUONDigit;
        d->SetDetElemId(detElemId);
        d->SetPadX(pad.GetIndices().GetFirst());
        d->SetPadY(pad.GetIndices().GetSecond());
        d->SetSignal(icharge);
        d->AddPhysicsSignal(d->Signal());
        d->SetCathode(cath);
        d->SetElectronics(pad.GetLocation().GetFirst(),
                          pad.GetLocation().GetSecond());
        digits.Add(d);   
      }       
      it->Next();
    }
    delete it;
  }
}