// $Id: CounterAlg.cpp,v 1.6 2007/05/10 17:37:49 hmd Exp $
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// 
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// Include files
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// GaudiKernel
// ============================================================================
#include "GaudiKernel/AlgFactory.h"
#include "GaudiKernel/RndmGenerators.h"
// ============================================================================
// GaudiAlg 
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#include "GaudiAlg/GaudiAlgorithm.h"
// ============================================================================

// ============================================================================
/** @file 
 *  Simple exmaple of usage of different "counters" 
 *
 *  @see GaudiAlgorithm
 *  @see StatEntity 
 *
 *  @author Vanya BELYAEV Ivan.Belyaev@lapp.in2p3.fr
 *  @date 2008-08-06
 */
// ============================================================================

// ============================================================================
/** @class CounterAlg 
 *  
 *  Simple algorithm whioch inllustartes the usage 
 *  of different "counters" 
 *
 *  @see GaudiAlgorithm
 *  @see StatEntity 
 *
 *  @author Vanya BELYAEV Ivan.Belyaev@lapp.in2p3.fr
 *  @date 2008-08-06
 */
// ============================================================================
class CounterAlg : public GaudiAlgorithm 
{
public:
  /** the only one essential method 
   *  @return status code 
   */
  virtual StatusCode execute () ;

  /** standard contructor 
   *  @param name algorithm istance name 
   *  @param pSvc pointer to Service Locator
   */
  CounterAlg 
  ( const std::string& name , 
    ISvcLocator*       pSvc ) 
    : GaudiAlgorithm ( name , pSvc ) 
  { setProperty( "StatPrint" , "true" ).ignore() ; }
  /// virtual protected dectrustor 
  virtual ~CounterAlg() {};
private:
  // default constructor is disabled 
  CounterAlg() ;
  // copy constructor is disabled 
  CounterAlg           ( const CounterAlg& ) ;
  // assignement operator is disabled 
  CounterAlg& operator=( const CounterAlg& ) ;
} ;
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// ============================================================================
DECLARE_ALGORITHM_FACTORY(CounterAlg)
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/** the only one essential method 
 *  @return status code 
 */
// ============================================================================
StatusCode CounterAlg::execute () 
{

  // count overall number of executions:
  ++counter("executed") ;
  
  Rndm::Numbers gauss   ( randSvc() , Rndm::Gauss   (   0.0 ,  1.0 ) ) ;
  Rndm::Numbers poisson ( randSvc() , Rndm::Poisson (   5.0        ) ) ;
  
  // 'accumulate' gauss
  const double value  = gauss() ;

  counter("gauss") += value ;
  counter("g2")    += value * value ;
  
  ( 0 < value ) ? ++counter("Gpos") : ++counter("Gneg") ;
  
  
  StatEntity& stat1 = counter("NG") ;
  StatEntity& stat2 = counter("G") ;
  
  const int num = (int) poisson() ;
  for ( int i = 0 ; i < num ; ++i ) 
  {
    stat1++ ;
    stat2+= gauss() ;
  }

  // assignement 
  counter("assign") = value ;
  
  // counter of efficiency 
  counter("eff")   += ( 0 < value ) ;
  
  // print the statistics every 1000 events 
  const StatEntity& executed = counter("executed") ;
  const int print  = (int) executed.flag() ;
  if ( 0 == print%1000 ) 
  {
    info () <<  " Event number "     << print << endmsg ;
    printStat() ; 
    info () << " Efficiency (binomial counter: \"eff\"): (" 
            << counter("eff").eff()    * 100.0  << " +- "
            << counter("eff").effErr() * 100.0  << ")%"<< endmsg ;
  }
  
  return StatusCode::SUCCESS ;
}
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