lemon/time_measure.h
author Akos Ladanyi <ladanyi@tmit.bme.hu>
Tue, 22 Apr 2008 18:12:58 +0200
changeset 153 976a014b3797
parent 120 137278093143
child 143 c3b45bb643b0
permissions -rw-r--r--
Convert the EPS files to PNG when generating the documentation
alpar@119
     1
/* -*- C++ -*-
alpar@119
     2
 *
alpar@119
     3
 * This file is a part of LEMON, a generic C++ optimization library
alpar@119
     4
 *
alpar@119
     5
 * Copyright (C) 2003-2008
alpar@119
     6
 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
alpar@119
     7
 * (Egervary Research Group on Combinatorial Optimization, EGRES).
alpar@119
     8
 *
alpar@119
     9
 * Permission to use, modify and distribute this software is granted
alpar@119
    10
 * provided that this copyright notice appears in all copies. For
alpar@119
    11
 * precise terms see the accompanying LICENSE file.
alpar@119
    12
 *
alpar@119
    13
 * This software is provided "AS IS" with no warranty of any kind,
alpar@119
    14
 * express or implied, and with no claim as to its suitability for any
alpar@119
    15
 * purpose.
alpar@119
    16
 *
alpar@119
    17
 */
alpar@119
    18
alpar@119
    19
#ifndef LEMON_TIME_MEASURE_H
alpar@119
    20
#define LEMON_TIME_MEASURE_H
alpar@119
    21
alpar@119
    22
///\ingroup timecount
alpar@119
    23
///\file
alpar@119
    24
///\brief Tools for measuring cpu usage
alpar@119
    25
deba@126
    26
#ifdef WIN32
deba@126
    27
#include <windows.h>
deba@126
    28
#include <cmath>
deba@126
    29
#else
alpar@119
    30
#include <sys/times.h>
deba@126
    31
#include <sys/time.h>
deba@126
    32
#endif
alpar@119
    33
alpar@119
    34
#include <fstream>
alpar@119
    35
#include <iostream>
alpar@119
    36
alpar@119
    37
namespace lemon {
alpar@119
    38
alpar@119
    39
  /// \addtogroup timecount
alpar@119
    40
  /// @{
alpar@119
    41
alpar@119
    42
  /// A class to store (cpu)time instances.
alpar@119
    43
alpar@119
    44
  /// This class stores five time values.
alpar@119
    45
  /// - a real time
alpar@119
    46
  /// - a user cpu time
alpar@119
    47
  /// - a system cpu time
alpar@119
    48
  /// - a user cpu time of children
alpar@119
    49
  /// - a system cpu time of children
alpar@119
    50
  ///
alpar@119
    51
  /// TimeStamp's can be added to or substracted from each other and
alpar@119
    52
  /// they can be pushed to a stream.
alpar@119
    53
  ///
alpar@119
    54
  /// In most cases, perhaps the \ref Timer or the \ref TimeReport
alpar@119
    55
  /// class is what you want to use instead.
alpar@119
    56
  ///
alpar@119
    57
  ///\author Alpar Juttner
alpar@119
    58
alpar@119
    59
  class TimeStamp
alpar@119
    60
  {
deba@126
    61
    double utime;
deba@126
    62
    double stime;
deba@126
    63
    double cutime;
deba@126
    64
    double cstime;
deba@126
    65
    double rtime;
alpar@119
    66
  
alpar@119
    67
    void _reset() { 
deba@126
    68
      utime = stime = cutime = cstime = rtime = 0;
alpar@119
    69
    }
alpar@119
    70
alpar@119
    71
  public:
alpar@119
    72
alpar@119
    73
    ///Read the current time values of the process
alpar@119
    74
    void stamp()
alpar@119
    75
    {
deba@126
    76
#ifndef WIN32
alpar@119
    77
      timeval tv;
deba@126
    78
      gettimeofday(&tv, 0);
deba@126
    79
      rtime=tv.tv_sec+double(tv.tv_usec)/1e6;
deba@126
    80
deba@126
    81
      tms ts;
deba@126
    82
      double tck=sysconf(_SC_CLK_TCK);
deba@126
    83
      times(&ts);
deba@126
    84
      utime=ts.tms_utime/tck;
deba@126
    85
      stime=ts.tms_stime/tck;
deba@126
    86
      cutime=ts.tms_cutime/tck;
deba@126
    87
      cstime=ts.tms_cstime/tck;
deba@126
    88
#else
deba@126
    89
      static const double ch = 4294967296.0e-7;
deba@126
    90
      static const double cl = 1.0e-7;
deba@126
    91
deba@126
    92
      FILETIME system;
deba@126
    93
      GetSystemTimeAsFileTime(&system);
deba@126
    94
      rtime = ch * system.dwHighDateTime + cl * system.dwLowDateTime;
deba@126
    95
deba@126
    96
      FILETIME create, exit, kernel, user;
deba@126
    97
      if (GetProcessTimes(GetCurrentProcess(),&create, &exit, &kernel, &user)) {
deba@126
    98
	utime = ch * user.dwHighDateTime + cl * user.dwLowDateTime;
deba@126
    99
	stime = ch * kernel.dwHighDateTime + cl * kernel.dwLowDateTime;
deba@126
   100
	cutime = 0;
deba@126
   101
	cstime = 0;
deba@126
   102
      } else {
deba@126
   103
	rtime = 0;
deba@126
   104
	utime = 0;
deba@126
   105
	stime = 0;
deba@126
   106
	cutime = 0;
deba@126
   107
	cstime = 0;
deba@126
   108
      }
deba@126
   109
#endif      
alpar@119
   110
    }
alpar@119
   111
  
alpar@119
   112
    /// Constructor initializing with zero
alpar@119
   113
    TimeStamp()
alpar@119
   114
    { _reset(); }
alpar@119
   115
    ///Constructor initializing with the current time values of the process
alpar@119
   116
    TimeStamp(void *) { stamp();}
alpar@119
   117
  
alpar@119
   118
    ///Set every time value to zero
alpar@119
   119
    TimeStamp &reset() {_reset();return *this;}
alpar@119
   120
alpar@119
   121
    ///\e
alpar@119
   122
    TimeStamp &operator+=(const TimeStamp &b)
alpar@119
   123
    {
deba@126
   124
      utime+=b.utime;
deba@126
   125
      stime+=b.stime;
deba@126
   126
      cutime+=b.cutime;
deba@126
   127
      cstime+=b.cstime;
deba@126
   128
      rtime+=b.rtime;
alpar@119
   129
      return *this;
alpar@119
   130
    }
alpar@119
   131
    ///\e
alpar@119
   132
    TimeStamp operator+(const TimeStamp &b) const
alpar@119
   133
    {
alpar@119
   134
      TimeStamp t(*this);
alpar@119
   135
      return t+=b;
alpar@119
   136
    }
alpar@119
   137
    ///\e
alpar@119
   138
    TimeStamp &operator-=(const TimeStamp &b)
alpar@119
   139
    {
deba@126
   140
      utime-=b.utime;
deba@126
   141
      stime-=b.stime;
deba@126
   142
      cutime-=b.cutime;
deba@126
   143
      cstime-=b.cstime;
deba@126
   144
      rtime-=b.rtime;
alpar@119
   145
      return *this;
alpar@119
   146
    }
alpar@119
   147
    ///\e
alpar@119
   148
    TimeStamp operator-(const TimeStamp &b) const
alpar@119
   149
    {
alpar@119
   150
      TimeStamp t(*this);
alpar@119
   151
      return t-=b;
alpar@119
   152
    }
alpar@119
   153
    ///\e
alpar@119
   154
    TimeStamp &operator*=(double b)
alpar@119
   155
    {
deba@126
   156
      utime*=b;
deba@126
   157
      stime*=b;
deba@126
   158
      cutime*=b;
deba@126
   159
      cstime*=b;
deba@126
   160
      rtime*=b;
alpar@119
   161
      return *this;
alpar@119
   162
    }
alpar@119
   163
    ///\e
alpar@119
   164
    TimeStamp operator*(double b) const
alpar@119
   165
    {
alpar@119
   166
      TimeStamp t(*this);
alpar@119
   167
      return t*=b;
alpar@119
   168
    }
alpar@119
   169
    friend TimeStamp operator*(double b,const TimeStamp &t);
alpar@119
   170
    ///\e
alpar@119
   171
    TimeStamp &operator/=(double b)
alpar@119
   172
    {
deba@126
   173
      utime/=b;
deba@126
   174
      stime/=b;
deba@126
   175
      cutime/=b;
deba@126
   176
      cstime/=b;
deba@126
   177
      rtime/=b;
alpar@119
   178
      return *this;
alpar@119
   179
    }
alpar@119
   180
    ///\e
alpar@119
   181
    TimeStamp operator/(double b) const
alpar@119
   182
    {
alpar@119
   183
      TimeStamp t(*this);
alpar@119
   184
      return t/=b;
alpar@119
   185
    }
alpar@119
   186
    ///The time ellapsed since the last call of stamp()
alpar@119
   187
    TimeStamp ellapsed() const
alpar@119
   188
    {
alpar@119
   189
      TimeStamp t(NULL);
alpar@119
   190
      return t-*this;
alpar@119
   191
    }
alpar@119
   192
  
alpar@119
   193
    friend std::ostream& operator<<(std::ostream& os,const TimeStamp &t);
alpar@119
   194
  
alpar@119
   195
    ///Gives back the user time of the process
alpar@119
   196
    double userTime() const
alpar@119
   197
    {
deba@126
   198
      return utime;
alpar@119
   199
    }
alpar@119
   200
    ///Gives back the system time of the process
alpar@119
   201
    double systemTime() const
alpar@119
   202
    {
deba@126
   203
      return stime;
alpar@119
   204
    }
alpar@119
   205
    ///Gives back the user time of the process' children
deba@126
   206
deba@126
   207
    ///\note On <tt>WIN32</tt> platform this value is not calculated. 
deba@126
   208
    ///
alpar@119
   209
    double cUserTime() const
alpar@119
   210
    {
deba@126
   211
      return cutime;
alpar@119
   212
    }
alpar@119
   213
    ///Gives back the user time of the process' children
deba@126
   214
deba@126
   215
    ///\note On <tt>WIN32</tt> platform this value is not calculated. 
deba@126
   216
    ///
alpar@119
   217
    double cSystemTime() const
alpar@119
   218
    {
deba@126
   219
      return cstime;
alpar@119
   220
    }
alpar@119
   221
    ///Gives back the real time
deba@126
   222
    double realTime() const {return rtime;}
alpar@119
   223
  };
alpar@119
   224
alpar@119
   225
  TimeStamp operator*(double b,const TimeStamp &t) 
alpar@119
   226
  {
alpar@119
   227
    return t*b;
alpar@119
   228
  }
alpar@119
   229
  
alpar@119
   230
  ///Prints the time counters
alpar@119
   231
alpar@119
   232
  ///Prints the time counters in the following form:
alpar@119
   233
  ///
alpar@119
   234
  /// <tt>u: XX.XXs s: XX.XXs cu: XX.XXs cs: XX.XXs real: XX.XXs</tt>
alpar@119
   235
  ///
alpar@119
   236
  /// where the values are the
alpar@119
   237
  /// \li \c u: user cpu time,
alpar@119
   238
  /// \li \c s: system cpu time,
alpar@119
   239
  /// \li \c cu: user cpu time of children,
alpar@119
   240
  /// \li \c cs: system cpu time of children,
alpar@119
   241
  /// \li \c real: real time.
alpar@119
   242
  /// \relates TimeStamp
deba@126
   243
  /// \note On <tt>WIN32</tt> platform the cummulative values are not
deba@126
   244
  /// calculated.
alpar@119
   245
  inline std::ostream& operator<<(std::ostream& os,const TimeStamp &t)
alpar@119
   246
  {
deba@126
   247
    os << "u: " << t.userTime() <<
deba@126
   248
      "s, s: " << t.systemTime() <<
deba@126
   249
      "s, cu: " << t.cUserTime() <<
deba@126
   250
      "s, cs: " << t.cSystemTime() <<
alpar@119
   251
      "s, real: " << t.realTime() << "s";
alpar@119
   252
    return os;
alpar@119
   253
  }
alpar@119
   254
alpar@119
   255
  ///Class for measuring the cpu time and real time usage of the process
alpar@119
   256
alpar@119
   257
  ///Class for measuring the cpu time and real time usage of the process.
alpar@119
   258
  ///It is quite easy-to-use, here is a short example.
alpar@119
   259
  ///\code
alpar@119
   260
  /// #include<lemon/time_measure.h>
alpar@119
   261
  /// #include<iostream>
alpar@119
   262
  ///
alpar@119
   263
  /// int main()
alpar@119
   264
  /// {
alpar@119
   265
  ///
alpar@119
   266
  ///   ...
alpar@119
   267
  ///
alpar@119
   268
  ///   Timer t;
alpar@119
   269
  ///   doSomething();
alpar@119
   270
  ///   std::cout << t << '\n';
alpar@119
   271
  ///   t.restart();
alpar@119
   272
  ///   doSomethingElse();
alpar@119
   273
  ///   std::cout << t << '\n';
alpar@119
   274
  ///
alpar@119
   275
  ///   ...
alpar@119
   276
  ///
alpar@119
   277
  /// }
alpar@119
   278
  ///\endcode
alpar@119
   279
  ///
alpar@119
   280
  ///The \ref Timer can also be \ref stop() "stopped" and
alpar@119
   281
  ///\ref start() "started" again, so it is possible to compute collected
alpar@119
   282
  ///running times.
alpar@119
   283
  ///
alpar@119
   284
  ///\warning Depending on the operation system and its actual configuration
alpar@119
   285
  ///the time counters have a certain (10ms on a typical Linux system)
alpar@119
   286
  ///granularity.
alpar@119
   287
  ///Therefore this tool is not appropriate to measure very short times.
alpar@119
   288
  ///Also, if you start and stop the timer very frequently, it could lead to
alpar@119
   289
  ///distorted results.
alpar@119
   290
  ///
alpar@119
   291
  ///\note If you want to measure the running time of the execution of a certain
alpar@119
   292
  ///function, consider the usage of \ref TimeReport instead.
alpar@119
   293
  ///
alpar@119
   294
  ///\todo This shouldn't be Unix (Linux) specific.
alpar@119
   295
  ///\sa TimeReport
alpar@119
   296
  ///
alpar@119
   297
  ///\author Alpar Juttner
alpar@119
   298
  class Timer
alpar@119
   299
  {
alpar@119
   300
    int _running; //Timer is running iff _running>0; (_running>=0 always holds)
alpar@119
   301
    TimeStamp start_time; //This is the relativ start-time if the timer
alpar@119
   302
                          //is _running, the collected _running time otherwise.
alpar@119
   303
    
alpar@119
   304
    void _reset() {if(_running) start_time.stamp(); else start_time.reset();}
alpar@119
   305
  
alpar@119
   306
  public: 
alpar@119
   307
    ///Constructor.
alpar@119
   308
alpar@119
   309
    ///\param run indicates whether or not the timer starts immediately.
alpar@119
   310
    ///
alpar@119
   311
    Timer(bool run=true) :_running(run) {_reset();}
alpar@119
   312
alpar@119
   313
    ///\name Control the state of the timer
alpar@119
   314
    ///Basically a Timer can be either running or stopped,
alpar@119
   315
    ///but it provides a bit finer control on the execution.
alpar@119
   316
    ///The \ref Timer also counts the number of \ref start()
alpar@119
   317
    ///executions, and is stops only after the same amount (or more)
alpar@119
   318
    ///\ref stop() "stop()"s. This can be useful e.g. to compute the running time
alpar@119
   319
    ///of recursive functions.
alpar@119
   320
    ///
alpar@119
   321
alpar@119
   322
    ///@{
alpar@119
   323
alpar@119
   324
    ///Reset and stop the time counters
alpar@119
   325
alpar@119
   326
    ///This function resets and stops the time counters
alpar@119
   327
    ///\sa restart()
alpar@119
   328
    void reset()
alpar@119
   329
    {
alpar@119
   330
      _running=0;
alpar@119
   331
      _reset();
alpar@119
   332
    }
alpar@119
   333
alpar@119
   334
    ///Start the time counters
alpar@119
   335
    
alpar@119
   336
    ///This function starts the time counters.
alpar@119
   337
    ///
alpar@119
   338
    ///If the timer is started more than ones, it will remain running
alpar@119
   339
    ///until the same amount of \ref stop() is called.
alpar@119
   340
    ///\sa stop()
alpar@119
   341
    void start() 
alpar@119
   342
    {
alpar@119
   343
      if(_running) _running++;
alpar@119
   344
      else {
alpar@119
   345
	_running=1;
alpar@119
   346
	TimeStamp t;
alpar@119
   347
	t.stamp();
alpar@119
   348
	start_time=t-start_time;
alpar@119
   349
      }
alpar@119
   350
    }
alpar@119
   351
alpar@119
   352
    
alpar@119
   353
    ///Stop the time counters
alpar@119
   354
alpar@119
   355
    ///This function stops the time counters. If start() was executed more than
alpar@119
   356
    ///once, then the same number of stop() execution is necessary the really
alpar@119
   357
    ///stop the timer.
alpar@119
   358
    /// 
alpar@119
   359
    ///\sa halt()
alpar@119
   360
    ///\sa start()
alpar@119
   361
    ///\sa restart()
alpar@119
   362
    ///\sa reset()
alpar@119
   363
alpar@119
   364
    void stop() 
alpar@119
   365
    {
alpar@119
   366
      if(_running && !--_running) {
alpar@119
   367
	TimeStamp t;
alpar@119
   368
	t.stamp();
alpar@119
   369
	start_time=t-start_time;
alpar@119
   370
      }
alpar@119
   371
    }
alpar@119
   372
alpar@119
   373
    ///Halt (i.e stop immediately) the time counters
alpar@119
   374
alpar@120
   375
    ///This function stops immediately the time counters, i.e. <tt>t.halt()</tt>
alpar@119
   376
    ///is a faster
alpar@119
   377
    ///equivalent of the following.
alpar@119
   378
    ///\code
alpar@119
   379
    ///  while(t.running()) t.stop()
alpar@119
   380
    ///\endcode
alpar@119
   381
    ///
alpar@119
   382
    ///
alpar@119
   383
    ///\sa stop()
alpar@119
   384
    ///\sa restart()
alpar@119
   385
    ///\sa reset()
alpar@119
   386
alpar@119
   387
    void halt() 
alpar@119
   388
    {
alpar@119
   389
      if(_running) {
alpar@119
   390
	_running=0;
alpar@119
   391
	TimeStamp t;
alpar@119
   392
	t.stamp();
alpar@119
   393
	start_time=t-start_time;
alpar@119
   394
      }
alpar@119
   395
    }
alpar@119
   396
alpar@119
   397
    ///Returns the running state of the timer
alpar@119
   398
alpar@119
   399
    ///This function returns the number of stop() exections that is
alpar@119
   400
    ///necessary to really stop the timer.
alpar@119
   401
    ///For example the timer
alpar@119
   402
    ///is running if and only if the return value is \c true
alpar@119
   403
    ///(i.e. greater than
alpar@119
   404
    ///zero).
alpar@119
   405
    int running()  { return _running; }
alpar@119
   406
    
alpar@119
   407
    
alpar@119
   408
    ///Restart the time counters
alpar@119
   409
alpar@119
   410
    ///This function is a shorthand for
alpar@119
   411
    ///a reset() and a start() calls.
alpar@119
   412
    ///
alpar@119
   413
    void restart() 
alpar@119
   414
    {
alpar@119
   415
      reset();
alpar@119
   416
      start();
alpar@119
   417
    }
alpar@119
   418
    
alpar@119
   419
    ///@}
alpar@119
   420
alpar@119
   421
    ///\name Query Functions for the ellapsed time
alpar@119
   422
alpar@119
   423
    ///@{
alpar@119
   424
alpar@119
   425
    ///Gives back the ellapsed user time of the process
alpar@119
   426
    double userTime() const
alpar@119
   427
    {
alpar@119
   428
      return operator TimeStamp().userTime();
alpar@119
   429
    }
alpar@119
   430
    ///Gives back the ellapsed system time of the process
alpar@119
   431
    double systemTime() const
alpar@119
   432
    {
alpar@119
   433
      return operator TimeStamp().systemTime();
alpar@119
   434
    }
alpar@119
   435
    ///Gives back the ellapsed user time of the process' children
deba@126
   436
deba@126
   437
    ///\note On <tt>WIN32</tt> platform this value is not calculated. 
deba@126
   438
    ///
alpar@119
   439
    double cUserTime() const
alpar@119
   440
    {
alpar@119
   441
      return operator TimeStamp().cUserTime();
alpar@119
   442
    }
alpar@119
   443
    ///Gives back the ellapsed user time of the process' children
deba@126
   444
deba@126
   445
    ///\note On <tt>WIN32</tt> platform this value is not calculated. 
deba@126
   446
    ///
alpar@119
   447
    double cSystemTime() const
alpar@119
   448
    {
alpar@119
   449
      return operator TimeStamp().cSystemTime();
alpar@119
   450
    }
alpar@119
   451
    ///Gives back the ellapsed real time
alpar@119
   452
    double realTime() const
alpar@119
   453
    {
alpar@119
   454
      return operator TimeStamp().realTime();
alpar@119
   455
    }
alpar@119
   456
    ///Computes the ellapsed time
alpar@119
   457
alpar@119
   458
    ///This conversion computes the ellapsed time, therefore you can print
alpar@119
   459
    ///the ellapsed time like this.
alpar@119
   460
    ///\code
alpar@119
   461
    ///  Timer t;
alpar@119
   462
    ///  doSomething();
alpar@119
   463
    ///  std::cout << t << '\n';
alpar@119
   464
    ///\endcode
alpar@119
   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
    ///@}
alpar@119
   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.
alpar@119
   479
  ///This example shows its usage.
alpar@119
   480
  ///\code
alpar@119
   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
alpar@119
   490
  ///\todo There is no test case for this
alpar@119
   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.
alpar@119
   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