lemon/time_measure.h
author Alpar Juttner <alpar@cs.elte.hu>
Thu, 24 Apr 2008 20:26:14 +0100
changeset 151 4d79daa40e9b
parent 120 137278093143
child 143 c3b45bb643b0
permissions -rw-r--r--
Turn on built in Doxygen STL support
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/* -*- C++ -*-
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 *
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 * This file is a part of LEMON, a generic C++ optimization library
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 *
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 * Copyright (C) 2003-2008
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 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
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 * (Egervary Research Group on Combinatorial Optimization, EGRES).
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 *
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 * Permission to use, modify and distribute this software is granted
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 * provided that this copyright notice appears in all copies. For
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 * precise terms see the accompanying LICENSE file.
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 *
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 * This software is provided "AS IS" with no warranty of any kind,
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 * express or implied, and with no claim as to its suitability for any
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 * purpose.
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 *
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 */
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#ifndef LEMON_TIME_MEASURE_H
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#define LEMON_TIME_MEASURE_H
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///\ingroup timecount
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///\file
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///\brief Tools for measuring cpu usage
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#ifdef WIN32
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#include <windows.h>
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#include <cmath>
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#else
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#include <sys/times.h>
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#include <sys/time.h>
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#endif
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#include <fstream>
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#include <iostream>
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namespace lemon {
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  /// \addtogroup timecount
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  /// @{
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  /// A class to store (cpu)time instances.
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  /// This class stores five time values.
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  /// - a real time
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  /// - a user cpu time
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  /// - a system cpu time
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  /// - a user cpu time of children
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  /// - a system cpu time of children
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  ///
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  /// TimeStamp's can be added to or substracted from each other and
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  /// they can be pushed to a stream.
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  ///
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  /// In most cases, perhaps the \ref Timer or the \ref TimeReport
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  /// class is what you want to use instead.
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  ///
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  ///\author Alpar Juttner
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  class TimeStamp
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  {
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    double utime;
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    double stime;
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    double cutime;
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    double cstime;
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    double rtime;
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    void _reset() { 
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      utime = stime = cutime = cstime = rtime = 0;
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    }
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  public:
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    ///Read the current time values of the process
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    void stamp()
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    {
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#ifndef WIN32
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      timeval tv;
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      gettimeofday(&tv, 0);
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      rtime=tv.tv_sec+double(tv.tv_usec)/1e6;
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      tms ts;
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      double tck=sysconf(_SC_CLK_TCK);
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      times(&ts);
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      utime=ts.tms_utime/tck;
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      stime=ts.tms_stime/tck;
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      cutime=ts.tms_cutime/tck;
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      cstime=ts.tms_cstime/tck;
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#else
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      static const double ch = 4294967296.0e-7;
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      static const double cl = 1.0e-7;
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      FILETIME system;
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      GetSystemTimeAsFileTime(&system);
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      rtime = ch * system.dwHighDateTime + cl * system.dwLowDateTime;
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      FILETIME create, exit, kernel, user;
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      if (GetProcessTimes(GetCurrentProcess(),&create, &exit, &kernel, &user)) {
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	utime = ch * user.dwHighDateTime + cl * user.dwLowDateTime;
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	stime = ch * kernel.dwHighDateTime + cl * kernel.dwLowDateTime;
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	cutime = 0;
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	cstime = 0;
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      } else {
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	rtime = 0;
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	utime = 0;
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	stime = 0;
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	cutime = 0;
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	cstime = 0;
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      }
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#endif      
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    }
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    /// Constructor initializing with zero
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    TimeStamp()
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    { _reset(); }
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    ///Constructor initializing with the current time values of the process
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    TimeStamp(void *) { stamp();}
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    ///Set every time value to zero
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    TimeStamp &reset() {_reset();return *this;}
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    ///\e
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    TimeStamp &operator+=(const TimeStamp &b)
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    {
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      utime+=b.utime;
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      stime+=b.stime;
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      cutime+=b.cutime;
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      cstime+=b.cstime;
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      rtime+=b.rtime;
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      return *this;
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    }
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    ///\e
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    TimeStamp operator+(const TimeStamp &b) const
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    {
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      TimeStamp t(*this);
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      return t+=b;
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    }
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    ///\e
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    TimeStamp &operator-=(const TimeStamp &b)
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    {
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      utime-=b.utime;
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      stime-=b.stime;
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      cutime-=b.cutime;
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      cstime-=b.cstime;
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      rtime-=b.rtime;
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      return *this;
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    }
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    ///\e
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    TimeStamp operator-(const TimeStamp &b) const
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    {
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      TimeStamp t(*this);
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      return t-=b;
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    }
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    ///\e
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    TimeStamp &operator*=(double b)
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    {
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      utime*=b;
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      stime*=b;
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      cutime*=b;
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      cstime*=b;
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      rtime*=b;
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      return *this;
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    }
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    ///\e
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    TimeStamp operator*(double b) const
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    {
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      TimeStamp t(*this);
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      return t*=b;
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    }
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    friend TimeStamp operator*(double b,const TimeStamp &t);
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    ///\e
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    TimeStamp &operator/=(double b)
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    {
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      utime/=b;
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      stime/=b;
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      cutime/=b;
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      cstime/=b;
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      rtime/=b;
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      return *this;
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    }
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    ///\e
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    TimeStamp operator/(double b) const
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    {
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      TimeStamp t(*this);
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      return t/=b;
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    }
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    ///The time ellapsed since the last call of stamp()
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    TimeStamp ellapsed() const
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    {
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      TimeStamp t(NULL);
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      return t-*this;
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    }
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    friend std::ostream& operator<<(std::ostream& os,const TimeStamp &t);
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    ///Gives back the user time of the process
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    double userTime() const
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    {
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      return utime;
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    }
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    ///Gives back the system time of the process
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    double systemTime() const
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    {
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      return stime;
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    }
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    ///Gives back the user time of the process' children
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    ///\note On <tt>WIN32</tt> platform this value is not calculated. 
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    ///
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    double cUserTime() const
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    {
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      return cutime;
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    }
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    ///Gives back the user time of the process' children
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    ///\note On <tt>WIN32</tt> platform this value is not calculated. 
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    ///
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    double cSystemTime() const
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    {
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      return cstime;
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    }
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    ///Gives back the real time
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    double realTime() const {return rtime;}
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  };
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  TimeStamp operator*(double b,const TimeStamp &t) 
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  {
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    return t*b;
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  }
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  ///Prints the time counters
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  ///Prints the time counters in the following form:
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  ///
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  /// <tt>u: XX.XXs s: XX.XXs cu: XX.XXs cs: XX.XXs real: XX.XXs</tt>
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  ///
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  /// where the values are the
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  /// \li \c u: user cpu time,
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  /// \li \c s: system cpu time,
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  /// \li \c cu: user cpu time of children,
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  /// \li \c cs: system cpu time of children,
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  /// \li \c real: real time.
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  /// \relates TimeStamp
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  /// \note On <tt>WIN32</tt> platform the cummulative values are not
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  /// calculated.
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  inline std::ostream& operator<<(std::ostream& os,const TimeStamp &t)
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  {
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    os << "u: " << t.userTime() <<
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      "s, s: " << t.systemTime() <<
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      "s, cu: " << t.cUserTime() <<
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      "s, cs: " << t.cSystemTime() <<
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      "s, real: " << t.realTime() << "s";
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    return os;
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  }
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  ///Class for measuring the cpu time and real time usage of the process
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  ///Class for measuring the cpu time and real time usage of the process.
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  ///It is quite easy-to-use, here is a short example.
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  ///\code
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  /// #include<lemon/time_measure.h>
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  /// #include<iostream>
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  ///
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  /// int main()
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  /// {
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  ///
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  ///   ...
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  ///
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  ///   Timer t;
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  ///   doSomething();
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  ///   std::cout << t << '\n';
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  ///   t.restart();
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  ///   doSomethingElse();
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  ///   std::cout << t << '\n';
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  ///
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  ///   ...
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  ///
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  /// }
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  ///\endcode
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  ///
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  ///The \ref Timer can also be \ref stop() "stopped" and
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  ///\ref start() "started" again, so it is possible to compute collected
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  ///running times.
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  ///
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  ///\warning Depending on the operation system and its actual configuration
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  ///the time counters have a certain (10ms on a typical Linux system)
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  ///granularity.
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  ///Therefore this tool is not appropriate to measure very short times.
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  ///Also, if you start and stop the timer very frequently, it could lead to
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  ///distorted results.
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  ///
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  ///\note If you want to measure the running time of the execution of a certain
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  ///function, consider the usage of \ref TimeReport instead.
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  ///
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  ///\todo This shouldn't be Unix (Linux) specific.
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  ///\sa TimeReport
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  ///
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  ///\author Alpar Juttner
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  class Timer
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  {
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    int _running; //Timer is running iff _running>0; (_running>=0 always holds)
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    TimeStamp start_time; //This is the relativ start-time if the timer
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                          //is _running, the collected _running time otherwise.
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    void _reset() {if(_running) start_time.stamp(); else start_time.reset();}
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  public: 
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    ///Constructor.
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    ///\param run indicates whether or not the timer starts immediately.
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    ///
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    Timer(bool run=true) :_running(run) {_reset();}
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    ///\name Control the state of the timer
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    ///Basically a Timer can be either running or stopped,
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    ///but it provides a bit finer control on the execution.
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    ///The \ref Timer also counts the number of \ref start()
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    ///executions, and is stops only after the same amount (or more)
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    ///\ref stop() "stop()"s. This can be useful e.g. to compute the running time
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    ///of recursive functions.
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    ///
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    ///@{
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    ///Reset and stop the time counters
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    ///This function resets and stops the time counters
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    ///\sa restart()
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    void reset()
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    {
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      _running=0;
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      _reset();
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    }
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    ///Start the time counters
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    ///This function starts the time counters.
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    ///
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    ///If the timer is started more than ones, it will remain running
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    ///until the same amount of \ref stop() is called.
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    ///\sa stop()
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    void start() 
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    {
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      if(_running) _running++;
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      else {
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	_running=1;
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	TimeStamp t;
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	t.stamp();
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	start_time=t-start_time;
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      }
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    }
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    ///Stop the time counters
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    ///This function stops the time counters. If start() was executed more than
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    ///once, then the same number of stop() execution is necessary the really
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    ///stop the timer.
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    /// 
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    ///\sa halt()
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    ///\sa start()
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    ///\sa restart()
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    ///\sa reset()
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    void stop() 
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    {
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      if(_running && !--_running) {
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	TimeStamp t;
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	t.stamp();
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	start_time=t-start_time;
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      }
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    }
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    ///Halt (i.e stop immediately) the time counters
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    ///This function stops immediately the time counters, i.e. <tt>t.halt()</tt>
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    ///is a faster
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    ///equivalent of the following.
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    ///\code
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    ///  while(t.running()) t.stop()
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    ///\endcode
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    ///
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    ///
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    ///\sa stop()
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    ///\sa restart()
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    ///\sa reset()
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    void halt() 
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    {
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      if(_running) {
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	_running=0;
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	TimeStamp t;
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	t.stamp();
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	start_time=t-start_time;
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      }
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    }
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    ///Returns the running state of the timer
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    ///This function returns the number of stop() exections that is
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    ///necessary to really stop the timer.
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    ///For example the timer
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    ///is running if and only if the return value is \c true
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    ///(i.e. greater than
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    ///zero).
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    int running()  { return _running; }
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    ///Restart the time counters
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    ///This function is a shorthand for
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    ///a reset() and a start() calls.
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    ///
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    void restart() 
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    {
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      reset();
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      start();
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    }
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    ///@}
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    ///\name Query Functions for the ellapsed time
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    ///@{
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    ///Gives back the ellapsed user time of the process
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    double userTime() const
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    {
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      return operator TimeStamp().userTime();
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    }
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    ///Gives back the ellapsed system time of the process
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    double systemTime() const
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    {
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      return operator TimeStamp().systemTime();
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    }
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    ///Gives back the ellapsed user time of the process' children
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   436
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    ///\note On <tt>WIN32</tt> platform this value is not calculated. 
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   438
    ///
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   439
    double cUserTime() const
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   440
    {
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   441
      return operator TimeStamp().cUserTime();
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   442
    }
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   443
    ///Gives back the ellapsed user time of the process' children
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   444
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   445
    ///\note On <tt>WIN32</tt> platform this value is not calculated. 
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   446
    ///
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   447
    double cSystemTime() const
alpar@119
   448
    {
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   449
      return operator TimeStamp().cSystemTime();
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   450
    }
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   451
    ///Gives back the ellapsed real time
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   452
    double realTime() const
alpar@119
   453
    {
alpar@119
   454
      return operator TimeStamp().realTime();
alpar@119
   455
    }
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   456
    ///Computes the ellapsed time
alpar@119
   457
alpar@119
   458
    ///This conversion computes the ellapsed time, therefore you can print
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   459
    ///the ellapsed time like this.
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   460
    ///\code
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   461
    ///  Timer t;
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   462
    ///  doSomething();
alpar@119
   463
    ///  std::cout << t << '\n';
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   464
    ///\endcode
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   465
    operator TimeStamp () const
alpar@119
   466
    {
alpar@119
   467
      TimeStamp t;
alpar@119
   468
      t.stamp();
alpar@119
   469
      return _running?t-start_time:start_time;
alpar@119
   470
    }
alpar@119
   471
alpar@119
   472
alpar@119
   473
    ///@}
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   474
  };
alpar@119
   475
alpar@119
   476
  ///Same as \ref Timer but prints a report on destruction.
alpar@119
   477
alpar@119
   478
  ///Same as \ref Timer but prints a report on destruction.
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   479
  ///This example shows its usage.
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   480
  ///\code
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   481
  ///  void myAlg(ListGraph &g,int n)
alpar@119
   482
  ///  {
alpar@119
   483
  ///    TimeReport tr("Running time of myAlg: ");
alpar@119
   484
  ///    ... //Here comes the algorithm
alpar@119
   485
  ///  }
alpar@119
   486
  ///\endcode
alpar@119
   487
  ///
alpar@119
   488
  ///\sa Timer
alpar@119
   489
  ///\sa NoTimeReport
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   490
  ///\todo There is no test case for this
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   491
  class TimeReport : public Timer 
alpar@119
   492
  {
alpar@119
   493
    std::string _title;
alpar@119
   494
    std::ostream &_os;
alpar@119
   495
  public:
alpar@119
   496
    ///\e
alpar@119
   497
alpar@119
   498
    ///\param title This text will be printed before the ellapsed time.
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   499
    ///\param os The stream to print the report to.
alpar@119
   500
    ///\param run Sets whether the timer should start immediately.
alpar@119
   501
alpar@119
   502
    TimeReport(std::string title,std::ostream &os=std::cerr,bool run=true) 
alpar@119
   503
      : Timer(run), _title(title), _os(os){}
alpar@119
   504
    ///\e Prints the ellapsed time on destruction.
alpar@119
   505
    ~TimeReport() 
alpar@119
   506
    {
alpar@119
   507
      _os << _title << *this << std::endl;
alpar@119
   508
    }
alpar@119
   509
  };
alpar@119
   510
      
alpar@119
   511
  ///'Do nothing' version of \ref TimeReport
alpar@119
   512
alpar@119
   513
  ///\sa TimeReport
alpar@119
   514
  ///
alpar@119
   515
  class NoTimeReport
alpar@119
   516
  {
alpar@119
   517
  public:
alpar@119
   518
    ///\e
alpar@119
   519
    NoTimeReport(std::string,std::ostream &,bool) {}
alpar@119
   520
    ///\e
alpar@119
   521
    NoTimeReport(std::string,std::ostream &) {}
alpar@119
   522
    ///\e
alpar@119
   523
    NoTimeReport(std::string) {}
alpar@119
   524
    ///\e Do nothing.
alpar@119
   525
    ~NoTimeReport() {}
alpar@119
   526
alpar@119
   527
    operator TimeStamp () const { return TimeStamp(); }
alpar@119
   528
    void reset() {}
alpar@119
   529
    void start() {}
alpar@119
   530
    void stop() {}
alpar@119
   531
    void halt() {} 
alpar@119
   532
    int running() { return 0; }
alpar@119
   533
    void restart() {}
alpar@119
   534
    double userTime() const { return 0; }
alpar@119
   535
    double systemTime() const { return 0; }
alpar@119
   536
    double cUserTime() const { return 0; }
alpar@119
   537
    double cSystemTime() const { return 0; }
alpar@119
   538
    double realTime() const { return 0; }
alpar@119
   539
  };
alpar@119
   540
      
alpar@119
   541
  ///Tool to measure the running time more exactly.
alpar@119
   542
  
alpar@119
   543
  ///This function calls \c f several times and returns the average
alpar@119
   544
  ///running time. The number of the executions will be choosen in such a way
alpar@119
   545
  ///that the full real running time will be roughly between \c min_time
alpar@119
   546
  ///and <tt>2*min_time</tt>.
alpar@119
   547
  ///\param f the function object to be measured.
alpar@119
   548
  ///\param min_time the minimum total running time.
alpar@119
   549
  ///\retval num if it is not \c NULL, then the actual
alpar@119
   550
  ///        number of execution of \c f will be written into <tt>*num</tt>.
alpar@119
   551
  ///\retval full_time if it is not \c NULL, then the actual
alpar@119
   552
  ///        total running time will be written into <tt>*full_time</tt>.
alpar@119
   553
  ///\return The average running time of \c f.
alpar@119
   554
  
alpar@119
   555
  template<class F>
alpar@119
   556
  TimeStamp runningTimeTest(F f,double min_time=10,unsigned int *num = NULL,
alpar@119
   557
                            TimeStamp *full_time=NULL)
alpar@119
   558
  {
alpar@119
   559
    TimeStamp full;
alpar@119
   560
    unsigned int total=0;
alpar@119
   561
    Timer t;
alpar@119
   562
    for(unsigned int tn=1;tn <= 1U<<31 && full.realTime()<=min_time; tn*=2) {
alpar@119
   563
      for(;total<tn;total++) f();
alpar@119
   564
      full=t;
alpar@119
   565
    }
alpar@119
   566
    if(num) *num=total;
alpar@119
   567
    if(full_time) *full_time=full;
alpar@119
   568
    return full/total;
alpar@119
   569
  }
alpar@119
   570
  
alpar@119
   571
  /// @}  
alpar@119
   572
alpar@119
   573
alpar@119
   574
} //namespace lemon
alpar@119
   575
alpar@119
   576
#endif //LEMON_TIME_MEASURE_H