[u/mrichter/AliRoot.git] / EMCAL / AliEMCALSDigitizer.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.                  *
 **************************************************************************/

/* $Id$ */

//_________________________________________________________________________
// This is a TTask that makes SDigits out of Hits
// A Summable Digits is the sum of all hits originating 
// from one in one tower of the EMCAL 
// A threshold for assignment of the primary to SDigit is applied 
//
// JLK 26-Jun-2008 Added explanation:
// SDigits need to hold the energy sum of the hits, but AliEMCALDigit
// can (should) only store amplitude.  Therefore, the SDigit energy is
// "digitized" before being stored and must be "calibrated" back to an
// energy before SDigits are summed to form true Digits
//
// SDigits are written to TreeS, branch "EMCAL"
// AliEMCALSDigitizer with all current parameters is written 
// to TreeS branch "AliEMCALSDigitizer".
// Both branches have the same title. If necessary one can produce 
// another set of SDigits with different parameters. Two versions
// can be distunguished using titles of the branches.
// User case:
// root [0] AliEMCALSDigitizer * s = new AliEMCALSDigitizer("galice.root")
// Warning in <TDatabasePDG::TDatabasePDG>: object already instantiated
// root [1] s->ExecuteTask()
//             // Makes SDigitis for all events stored in galice.root
// root [2] s->SetPedestalParameter(0.001)
//             // One can change parameters of digitization
// root [3] s->SetSDigitsBranch("Redestal 0.001")
//             // and write them into the new branch
// root [4] s->ExeciteTask("deb all tim")
//             // available parameters:
//             deb - print # of produced SDigitis
//             deb all  - print # and list of produced SDigits
//             tim - print benchmarking information
//
//*-- Author : Sahal Yacoob (LBL)
// based on  : AliPHOSSDigitzer 
// Modif: 
//  August 2002 Yves Schutz: clone PHOS as closely as possible and intoduction
Commit	Line	Data
ffa6d63b	1	/*************************************************************************
61e0abb5	2	* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
	3	* *
	4	* Author: The ALICE Off-line Project. *
	5	* Contributors are mentioned in the code where appropriate. *
	6	* *
	7	* Permission to use, copy, modify and distribute this software and its *
	8	* documentation strictly for non-commercial purposes is hereby granted *
	9	* without fee, provided that the above copyright notice appears in all *
	10	* copies and that both the copyright notice and this permission notice *
	11	* appear in the supporting documentation. The authors make no claims *
	12	* about the suitability of this software for any purpose. It is *
	13	* provided "as is" without express or implied warranty. *
	14	**************************************************************************/
	15
	16	/* $Id$ */
	17
	18	//_________________________________________________________________________
	19	// This is a TTask that makes SDigits out of Hits
	20	// A Summable Digits is the sum of all hits originating
ffa6d63b	21	// from one in one tower of the EMCAL
61e0abb5	22	// A threshold for assignment of the primary to SDigit is applied
ab6a174f	23	//
	24	// JLK 26-Jun-2008 Added explanation:
	25	// SDigits need to hold the energy sum of the hits, but AliEMCALDigit
	26	// can (should) only store amplitude. Therefore, the SDigit energy is
	27	// "digitized" before being stored and must be "calibrated" back to an
	28	// energy before SDigits are summed to form true Digits
	29	//
61e0abb5	30	// SDigits are written to TreeS, branch "EMCAL"
	31	// AliEMCALSDigitizer with all current parameters is written
	32	// to TreeS branch "AliEMCALSDigitizer".
	33	// Both branches have the same title. If necessary one can produce
	34	// another set of SDigits with different parameters. Two versions
	35	// can be distunguished using titles of the branches.
	36	// User case:
	37	// root [0] AliEMCALSDigitizer * s = new AliEMCALSDigitizer("galice.root")
	38	// Warning in <TDatabasePDG::TDatabasePDG>: object already instantiated
	39	// root [1] s->ExecuteTask()
	40	// // Makes SDigitis for all events stored in galice.root
	41	// root [2] s->SetPedestalParameter(0.001)
	42	// // One can change parameters of digitization
	43	// root [3] s->SetSDigitsBranch("Redestal 0.001")
	44	// // and write them into the new branch
	45	// root [4] s->ExeciteTask("deb all tim")
	46	// // available parameters:
	47	// deb - print # of produced SDigitis
	48	// deb all - print # and list of produced SDigits
	49	// tim - print benchmarking information
	50	//
ffa6d63b	51	//*-- Author : Sahal Yacoob (LBL)
ffa6d63b	52	// based on : AliPHOSSDigitzer
05a92d59	53	// Modif:
	54	// August 2002 Yves Schutz: clone PHOS as closely as possible and intoduction
	55