/data/refman/pasoursint/CMSSW_6_1_1/src/DataFormats/MuonDetId/src/CSCIndexer.cc

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#include <DataFormats/MuonDetId/interface/CSCIndexer.h>
#include <iostream>

void CSCIndexer::fillChamberLabel() const {
  // Fill the member vector which permits decoding of the linear chamber index
  // Logically const since initializes cache only,
  // Beware that the ME42 indices 235-270 within this vector do NOT correspond to
  // their 'real' linear indices (which are 469-504 for +z)
   chamberLabel.resize( 271 ); // one more than #chambers per endcap. Includes ME42.
   IndexType count = 0;
   chamberLabel[count] = 0;

   for ( IndexType is = 1 ; is != 5; ++is ) {
      IndexType irmax = ringsInStation(is);
      for ( IndexType ir = 1; ir != irmax+1; ++ir ) {
         IndexType icmax = chambersInRingOfStation(is, ir);
         for ( IndexType ic = 1; ic != icmax+1; ++ic ) {
           chamberLabel[ ++count ] = is*1000 + ir*100 + ic ;
         }
      } 
   }
}

CSCDetId CSCIndexer::detIdFromChamberIndex_OLD( IndexType ici ) const {

  // Will not work as is for ME42
  // ============================

  IndexType ie = 1;
  if (ici > 234 ) {
     ie = 2;
     ici -= 234; 
  }
  // Now ici is in range 1-234 (assuming valid input in range 1-468)

  // MEij pairs...
  const IndexType station[] = {0,1,1,1,2,2,3,3,4};
  const IndexType ring[]    = {0,1,2,3,1,2,1,2,1};

  // MEij preceding a given MEij matching linear index above
  const IndexType prevs[] =  {0,0,1,1,1,2,2,3,3}; 
  const IndexType prevr[] =  {0,0,1,2,3,1,2,1,2};

  IndexType is = 4;
  IndexType ir = 1;
  for ( IndexType i = 2; i<=8; ++i) {
    IndexType js = station[i];
    IndexType jr = ring[i];
    // if it's before start of MEjs/jr then it's in the previous MEis/ir
      if ( ici < startChamberIndexInEndcap(ie,js,jr) ) {
        is = prevs[i];
        ir = prevr[i];
        break;
      }
      // otherwise it's in ME41
  }
  IndexType ic = ici - startChamberIndexInEndcap(ie,is,ir) + 1;

  return CSCDetId( ie, is, ir, ic );
}
 
CSCDetId CSCIndexer::detIdFromChamberIndex( IndexType ici ) const {
  // Expected range of input range argument is 1-540.
  // 1-468 for CSCs installed at 2008 start-up. 469-540 for ME42.

  IndexType ie = 1;
  if ( ici > 468 ) {
    // ME42
    ici -= 234; // now in range 235-306
    if ( ici > 270 ) { // -z
      ie = 2;
      ici -= 36; // now in range 235-270
    }
  }
  else { // in range 1-468
    if ( ici > 234 ) { // -z
      ie = 2;
      ici -= 234; // now in range 1-234
    }
  }
  if (chamberLabel.empty()) fillChamberLabel();
  IndexType label = chamberLabel[ici];    
  return detIdFromChamberLabel( ie, label );
}

CSCIndexer::IndexType CSCIndexer::chamberLabelFromChamberIndex( IndexType ici ) const {
  // This is just for cross-checking

  // Expected range of input range argument is 1-540.
  // 1-468 for CSCs installed at 2008 start-up. 469-540 for ME42.

  if ( ici > 468 ) {
    // ME42
    ici -= 234; // now in range 235-306
    if ( ici > 270 ) { // -z
      ici -= 36; // now in range 235-270
    }
  }
  else { // in range 1-468
    if ( ici > 234 ) { // -z
      ici -= 234; // now in range 1-234
    }
  }
  if (chamberLabel.empty()) fillChamberLabel();
  return chamberLabel[ici];  

}

CSCDetId CSCIndexer::detIdFromChamberLabel( IndexType ie, IndexType label ) const {

  IndexType is = label/1000;
  label -= is*1000;
  IndexType ir = label/100;
  label -= ir*100;
  IndexType ic = label;

  return CSCDetId( ie, is, ir, ic );
}

CSCDetId CSCIndexer::detIdFromLayerIndex( IndexType ili ) const {

  IndexType il = (ili-1)%6 + 1;
  IndexType ici = (ili-1)/6 + 1;
  CSCDetId id = detIdFromChamberIndex( ici ); 

  return CSCDetId(id.endcap(), id.station(), id.ring(), id.chamber(), il);
}

std::pair<CSCDetId, CSCIndexer::IndexType>  CSCIndexer::detIdFromStripChannelIndex( LongIndexType isi ) const {

  const LongIndexType lastnonme42 = 217728; // channels in 2008 installed chambers
  const LongIndexType lastplusznonme42 = 108864; // = 217728/2
  const LongIndexType firstme13  = 34561; // First channel of ME13
  const LongIndexType lastme13   = 48384; // Last channel of ME13

  const IndexType lastnonme42layer = 2808;
  const IndexType lastplusznonme42layer = 1404; // = 2808/2
  const IndexType firstme13layer  = 433; // = 72*6 + 1 (ME13 chambers are 72-108 in range 1-234)
  const IndexType lastme13layer   = 648; // = 108*6

  // All chambers but ME13 have 80 channels
  IndexType nchan = 80;

  // Set endcap to +z. This should work for ME42 channels too, since we don't need to calculate its endcap explicitly.
  IndexType ie = 1;

  LongIndexType istart = 0;
  IndexType layerOffset = 0;

  if ( isi <= lastnonme42 ) {   
    // Chambers as of 2008 Installation

    if ( isi > lastplusznonme42 ) {
      ie = 2;
      isi -= lastplusznonme42;
    }
        
    if ( isi > lastme13 ) { // after ME13
      istart = lastme13;
      layerOffset = lastme13layer;
    }
    else if ( isi >= firstme13 ) { // ME13
      istart = firstme13 - 1;
      layerOffset = firstme13layer - 1;
      nchan = 64;
    }
  }
  else {
     // ME42 chambers

    istart = lastnonme42;
    layerOffset = lastnonme42layer;
  }

   isi -= istart; // remove earlier group(s)
   IndexType ichan = (isi-1)%nchan + 1;
   IndexType ili = (isi-1)/nchan + 1;
   ili += layerOffset; // add appropriate offset for earlier group(s)
   if ( ie != 1 ) ili+= lastplusznonme42layer; // add offset to -z endcap; ME42 doesn't need this.
        
   return std::pair<CSCDetId, IndexType>(detIdFromLayerIndex(ili), ichan);
}


std::pair<CSCDetId, CSCIndexer::IndexType>  CSCIndexer::detIdFromChipIndex( IndexType ici ) const {

  const LongIndexType lastnonme42 = 13608; // chips in 2008 installed chambers
  const LongIndexType lastplusznonme42 = 6804; // = 13608/2
  const LongIndexType firstme13  = 2161; // First channel of ME13
  const LongIndexType lastme13   = 3024; // Last channel of ME13

  const IndexType lastnonme42layer = 2808;
  const IndexType lastplusznonme42layer = 1404; // = 2808/2
  const IndexType firstme13layer  = 433; // = 72*6 + 1 (ME13 chambers are 72-108 in range 1-234)
  const IndexType lastme13layer   = 648; // = 108*6

  // All chambers but ME13 have 5 chips/layer
  IndexType nchipPerLayer = 5;

  // Set endcap to +z. This should work for ME42 channels too, since we don't need to calculate its endcap explicitly.
  IndexType ie = 1;

  LongIndexType istart = 0;
  IndexType layerOffset = 0;

  if ( ici <= lastnonme42 ) {   
    // Chambers as of 2008 Installation

    if ( ici > lastplusznonme42 ) {
      ie = 2;
      ici -= lastplusznonme42;
    }
        
    if ( ici > lastme13 ) { // after ME13
      istart = lastme13;
      layerOffset = lastme13layer;
    }
    else if ( ici >= firstme13 ) { // ME13
      istart = firstme13 - 1;
      layerOffset = firstme13layer - 1;
      nchipPerLayer = 4;
    }
  }
  else {
     // ME42 chambers

    istart = lastnonme42;
    layerOffset = lastnonme42layer;
  }

   ici -= istart; // remove earlier group(s)
   IndexType ichip = (ici-1)%nchipPerLayer + 1;
   IndexType ili = (ici-1)/nchipPerLayer + 1;
   ili += layerOffset; // add appropriate offset for earlier group(s)
   if ( ie != 1 ) ili+= lastplusznonme42layer; // add offset to -z endcap; ME42 doesn't need this.
        
   return std::pair<CSCDetId, IndexType>(detIdFromLayerIndex(ili), ichip);
}

int CSCIndexer::dbIndex(const CSCDetId & id, int & channel)
{
  int ec = id.endcap();
  int st = id.station();
  int rg = id.ring();
  int ch = id.chamber();
  int la = id.layer();

  // The channels of ME1A are channels 65-80 of ME11
  if(st == 1 && rg == 4)
    {
      rg = 1;
      if(channel <= 16) channel += 64; // no trapping for any bizarreness
    }
  return ec*100000 + st*10000 + rg*1000 + ch*10 + la;
}