lemon/time_measure.h
author Peter Kovacs <kpeter@inf.elte.hu>
Sun, 30 Nov 2008 00:48:07 +0100
changeset 392 db3251947eba
parent 313 64f8f7cc6168
child 440 88ed40ad0d4f
child 482 55111a054b2e
permissions -rw-r--r--
Rename flowInit() to init() in Preflow (#176)
alpar@209
     1
/* -*- mode: C++; indent-tabs-mode: nil; -*-
alpar@119
     2
 *
alpar@209
     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
alpar@143
    27
#define WIN32_LEAN_AND_MEAN
alpar@143
    28
#define NOMINMAX
deba@126
    29
#include <windows.h>
deba@126
    30
#include <cmath>
deba@126
    31
#else
alpar@119
    32
#include <sys/times.h>
deba@126
    33
#include <sys/time.h>
deba@126
    34
#endif
alpar@119
    35
alpar@143
    36
#include <string>
alpar@119
    37
#include <fstream>
alpar@119
    38
#include <iostream>
alpar@119
    39
alpar@119
    40
namespace lemon {
alpar@119
    41
alpar@119
    42
  /// \addtogroup timecount
alpar@119
    43
  /// @{
alpar@119
    44
alpar@119
    45
  /// A class to store (cpu)time instances.
alpar@119
    46
alpar@119
    47
  /// This class stores five time values.
alpar@119
    48
  /// - a real time
alpar@119
    49
  /// - a user cpu time
alpar@119
    50
  /// - a system cpu time
alpar@119
    51
  /// - a user cpu time of children
alpar@119
    52
  /// - a system cpu time of children
alpar@119
    53
  ///
alpar@119
    54
  /// TimeStamp's can be added to or substracted from each other and
alpar@119
    55
  /// they can be pushed to a stream.
alpar@119
    56
  ///
alpar@119
    57
  /// In most cases, perhaps the \ref Timer or the \ref TimeReport
alpar@119
    58
  /// class is what you want to use instead.
alpar@119
    59
alpar@119
    60
  class TimeStamp
alpar@119
    61
  {
deba@126
    62
    double utime;
deba@126
    63
    double stime;
deba@126
    64
    double cutime;
deba@126
    65
    double cstime;
deba@126
    66
    double rtime;
alpar@209
    67
alpar@209
    68
    void _reset() {
deba@126
    69
      utime = stime = cutime = cstime = rtime = 0;
alpar@119
    70
    }
alpar@119
    71
alpar@119
    72
  public:
alpar@119
    73
alpar@119
    74
    ///Read the current time values of the process
alpar@119
    75
    void stamp()
alpar@119
    76
    {
deba@126
    77
#ifndef WIN32
alpar@119
    78
      timeval tv;
deba@126
    79
      gettimeofday(&tv, 0);
deba@126
    80
      rtime=tv.tv_sec+double(tv.tv_usec)/1e6;
deba@126
    81
deba@126
    82
      tms ts;
deba@126
    83
      double tck=sysconf(_SC_CLK_TCK);
deba@126
    84
      times(&ts);
deba@126
    85
      utime=ts.tms_utime/tck;
deba@126
    86
      stime=ts.tms_stime/tck;
deba@126
    87
      cutime=ts.tms_cutime/tck;
deba@126
    88
      cstime=ts.tms_cstime/tck;
deba@126
    89
#else
deba@126
    90
      static const double ch = 4294967296.0e-7;
deba@126
    91
      static const double cl = 1.0e-7;
deba@126
    92
deba@126
    93
      FILETIME system;
deba@126
    94
      GetSystemTimeAsFileTime(&system);
deba@126
    95
      rtime = ch * system.dwHighDateTime + cl * system.dwLowDateTime;
deba@126
    96
deba@126
    97
      FILETIME create, exit, kernel, user;
deba@126
    98
      if (GetProcessTimes(GetCurrentProcess(),&create, &exit, &kernel, &user)) {
alpar@209
    99
        utime = ch * user.dwHighDateTime + cl * user.dwLowDateTime;
alpar@209
   100
        stime = ch * kernel.dwHighDateTime + cl * kernel.dwLowDateTime;
alpar@209
   101
        cutime = 0;
alpar@209
   102
        cstime = 0;
deba@126
   103
      } else {
alpar@209
   104
        rtime = 0;
alpar@209
   105
        utime = 0;
alpar@209
   106
        stime = 0;
alpar@209
   107
        cutime = 0;
alpar@209
   108
        cstime = 0;
deba@126
   109
      }
alpar@209
   110
#endif
alpar@119
   111
    }
alpar@209
   112
alpar@119
   113
    /// Constructor initializing with zero
alpar@119
   114
    TimeStamp()
alpar@119
   115
    { _reset(); }
alpar@119
   116
    ///Constructor initializing with the current time values of the process
alpar@119
   117
    TimeStamp(void *) { stamp();}
alpar@209
   118
alpar@119
   119
    ///Set every time value to zero
alpar@119
   120
    TimeStamp &reset() {_reset();return *this;}
alpar@119
   121
alpar@119
   122
    ///\e
alpar@119
   123
    TimeStamp &operator+=(const TimeStamp &b)
alpar@119
   124
    {
deba@126
   125
      utime+=b.utime;
deba@126
   126
      stime+=b.stime;
deba@126
   127
      cutime+=b.cutime;
deba@126
   128
      cstime+=b.cstime;
deba@126
   129
      rtime+=b.rtime;
alpar@119
   130
      return *this;
alpar@119
   131
    }
alpar@119
   132
    ///\e
alpar@119
   133
    TimeStamp operator+(const TimeStamp &b) const
alpar@119
   134
    {
alpar@119
   135
      TimeStamp t(*this);
alpar@119
   136
      return t+=b;
alpar@119
   137
    }
alpar@119
   138
    ///\e
alpar@119
   139
    TimeStamp &operator-=(const TimeStamp &b)
alpar@119
   140
    {
deba@126
   141
      utime-=b.utime;
deba@126
   142
      stime-=b.stime;
deba@126
   143
      cutime-=b.cutime;
deba@126
   144
      cstime-=b.cstime;
deba@126
   145
      rtime-=b.rtime;
alpar@119
   146
      return *this;
alpar@119
   147
    }
alpar@119
   148
    ///\e
alpar@119
   149
    TimeStamp operator-(const TimeStamp &b) const
alpar@119
   150
    {
alpar@119
   151
      TimeStamp t(*this);
alpar@119
   152
      return t-=b;
alpar@119
   153
    }
alpar@119
   154
    ///\e
alpar@119
   155
    TimeStamp &operator*=(double b)
alpar@119
   156
    {
deba@126
   157
      utime*=b;
deba@126
   158
      stime*=b;
deba@126
   159
      cutime*=b;
deba@126
   160
      cstime*=b;
deba@126
   161
      rtime*=b;
alpar@119
   162
      return *this;
alpar@119
   163
    }
alpar@119
   164
    ///\e
alpar@119
   165
    TimeStamp operator*(double b) const
alpar@119
   166
    {
alpar@119
   167
      TimeStamp t(*this);
alpar@119
   168
      return t*=b;
alpar@119
   169
    }
alpar@119
   170
    friend TimeStamp operator*(double b,const TimeStamp &t);
alpar@119
   171
    ///\e
alpar@119
   172
    TimeStamp &operator/=(double b)
alpar@119
   173
    {
deba@126
   174
      utime/=b;
deba@126
   175
      stime/=b;
deba@126
   176
      cutime/=b;
deba@126
   177
      cstime/=b;
deba@126
   178
      rtime/=b;
alpar@119
   179
      return *this;
alpar@119
   180
    }
alpar@119
   181
    ///\e
alpar@119
   182
    TimeStamp operator/(double b) const
alpar@119
   183
    {
alpar@119
   184
      TimeStamp t(*this);
alpar@119
   185
      return t/=b;
alpar@119
   186
    }
alpar@119
   187
    ///The time ellapsed since the last call of stamp()
alpar@119
   188
    TimeStamp ellapsed() const
alpar@119
   189
    {
alpar@119
   190
      TimeStamp t(NULL);
alpar@119
   191
      return t-*this;
alpar@119
   192
    }
alpar@209
   193
alpar@119
   194
    friend std::ostream& operator<<(std::ostream& os,const TimeStamp &t);
alpar@209
   195
alpar@119
   196
    ///Gives back the user time of the process
alpar@119
   197
    double userTime() const
alpar@119
   198
    {
deba@126
   199
      return utime;
alpar@119
   200
    }
alpar@119
   201
    ///Gives back the system time of the process
alpar@119
   202
    double systemTime() const
alpar@119
   203
    {
deba@126
   204
      return stime;
alpar@119
   205
    }
alpar@119
   206
    ///Gives back the user time of the process' children
deba@126
   207
alpar@209
   208
    ///\note On <tt>WIN32</tt> platform this value is not calculated.
deba@126
   209
    ///
alpar@119
   210
    double cUserTime() const
alpar@119
   211
    {
deba@126
   212
      return cutime;
alpar@119
   213
    }
alpar@119
   214
    ///Gives back the user time of the process' children
deba@126
   215
alpar@209
   216
    ///\note On <tt>WIN32</tt> platform this value is not calculated.
deba@126
   217
    ///
alpar@119
   218
    double cSystemTime() const
alpar@119
   219
    {
deba@126
   220
      return cstime;
alpar@119
   221
    }
alpar@119
   222
    ///Gives back the real time
deba@126
   223
    double realTime() const {return rtime;}
alpar@119
   224
  };
alpar@119
   225
alpar@209
   226
  TimeStamp operator*(double b,const TimeStamp &t)
alpar@119
   227
  {
alpar@119
   228
    return t*b;
alpar@119
   229
  }
alpar@209
   230
alpar@119
   231
  ///Prints the time counters
alpar@119
   232
alpar@119
   233
  ///Prints the time counters in the following form:
alpar@119
   234
  ///
alpar@119
   235
  /// <tt>u: XX.XXs s: XX.XXs cu: XX.XXs cs: XX.XXs real: XX.XXs</tt>
alpar@119
   236
  ///
alpar@119
   237
  /// where the values are the
alpar@119
   238
  /// \li \c u: user cpu time,
alpar@119
   239
  /// \li \c s: system cpu time,
alpar@119
   240
  /// \li \c cu: user cpu time of children,
alpar@119
   241
  /// \li \c cs: system cpu time of children,
alpar@119
   242
  /// \li \c real: real time.
alpar@119
   243
  /// \relates TimeStamp
deba@126
   244
  /// \note On <tt>WIN32</tt> platform the cummulative values are not
deba@126
   245
  /// calculated.
alpar@119
   246
  inline std::ostream& operator<<(std::ostream& os,const TimeStamp &t)
alpar@119
   247
  {
deba@126
   248
    os << "u: " << t.userTime() <<
deba@126
   249
      "s, s: " << t.systemTime() <<
deba@126
   250
      "s, cu: " << t.cUserTime() <<
deba@126
   251
      "s, cs: " << t.cSystemTime() <<
alpar@119
   252
      "s, real: " << t.realTime() << "s";
alpar@119
   253
    return os;
alpar@119
   254
  }
alpar@119
   255
alpar@119
   256
  ///Class for measuring the cpu time and real time usage of the process
alpar@119
   257
alpar@119
   258
  ///Class for measuring the cpu time and real time usage of the process.
alpar@119
   259
  ///It is quite easy-to-use, here is a short example.
alpar@119
   260
  ///\code
alpar@119
   261
  /// #include<lemon/time_measure.h>
alpar@119
   262
  /// #include<iostream>
alpar@119
   263
  ///
alpar@119
   264
  /// int main()
alpar@119
   265
  /// {
alpar@119
   266
  ///
alpar@119
   267
  ///   ...
alpar@119
   268
  ///
alpar@119
   269
  ///   Timer t;
alpar@119
   270
  ///   doSomething();
alpar@119
   271
  ///   std::cout << t << '\n';
alpar@119
   272
  ///   t.restart();
alpar@119
   273
  ///   doSomethingElse();
alpar@119
   274
  ///   std::cout << t << '\n';
alpar@119
   275
  ///
alpar@119
   276
  ///   ...
alpar@119
   277
  ///
alpar@119
   278
  /// }
alpar@119
   279
  ///\endcode
alpar@119
   280
  ///
alpar@119
   281
  ///The \ref Timer can also be \ref stop() "stopped" and
alpar@119
   282
  ///\ref start() "started" again, so it is possible to compute collected
alpar@119
   283
  ///running times.
alpar@119
   284
  ///
alpar@119
   285
  ///\warning Depending on the operation system and its actual configuration
alpar@119
   286
  ///the time counters have a certain (10ms on a typical Linux system)
alpar@119
   287
  ///granularity.
alpar@119
   288
  ///Therefore this tool is not appropriate to measure very short times.
alpar@119
   289
  ///Also, if you start and stop the timer very frequently, it could lead to
alpar@119
   290
  ///distorted results.
alpar@119
   291
  ///
alpar@119
   292
  ///\note If you want to measure the running time of the execution of a certain
alpar@119
   293
  ///function, consider the usage of \ref TimeReport instead.
alpar@119
   294
  ///
alpar@119
   295
  ///\sa TimeReport
alpar@119
   296
  class Timer
alpar@119
   297
  {
alpar@119
   298
    int _running; //Timer is running iff _running>0; (_running>=0 always holds)
alpar@119
   299
    TimeStamp start_time; //This is the relativ start-time if the timer
alpar@119
   300
                          //is _running, the collected _running time otherwise.
alpar@209
   301
alpar@119
   302
    void _reset() {if(_running) start_time.stamp(); else start_time.reset();}
alpar@209
   303
alpar@209
   304
  public:
alpar@119
   305
    ///Constructor.
alpar@119
   306
alpar@119
   307
    ///\param run indicates whether or not the timer starts immediately.
alpar@119
   308
    ///
alpar@119
   309
    Timer(bool run=true) :_running(run) {_reset();}
alpar@119
   310
alpar@119
   311
    ///\name Control the state of the timer
alpar@119
   312
    ///Basically a Timer can be either running or stopped,
alpar@119
   313
    ///but it provides a bit finer control on the execution.
kpeter@314
   314
    ///The \ref lemon::Timer "Timer" also counts the number of
kpeter@314
   315
    ///\ref lemon::Timer::start() "start()" executions, and it stops
kpeter@313
   316
    ///only after the same amount (or more) \ref lemon::Timer::stop()
kpeter@313
   317
    ///"stop()"s. This can be useful e.g. to compute the running time
alpar@119
   318
    ///of recursive functions.
alpar@119
   319
alpar@119
   320
    ///@{
alpar@119
   321
alpar@119
   322
    ///Reset and stop the time counters
alpar@119
   323
alpar@119
   324
    ///This function resets and stops the time counters
alpar@119
   325
    ///\sa restart()
alpar@119
   326
    void reset()
alpar@119
   327
    {
alpar@119
   328
      _running=0;
alpar@119
   329
      _reset();
alpar@119
   330
    }
alpar@119
   331
alpar@119
   332
    ///Start the time counters
alpar@209
   333
alpar@119
   334
    ///This function starts the time counters.
alpar@119
   335
    ///
alpar@119
   336
    ///If the timer is started more than ones, it will remain running
alpar@119
   337
    ///until the same amount of \ref stop() is called.
alpar@119
   338
    ///\sa stop()
alpar@209
   339
    void start()
alpar@119
   340
    {
alpar@119
   341
      if(_running) _running++;
alpar@119
   342
      else {
alpar@209
   343
        _running=1;
alpar@209
   344
        TimeStamp t;
alpar@209
   345
        t.stamp();
alpar@209
   346
        start_time=t-start_time;
alpar@119
   347
      }
alpar@119
   348
    }
alpar@119
   349
alpar@209
   350
alpar@119
   351
    ///Stop the time counters
alpar@119
   352
alpar@119
   353
    ///This function stops the time counters. If start() was executed more than
alpar@119
   354
    ///once, then the same number of stop() execution is necessary the really
alpar@119
   355
    ///stop the timer.
alpar@209
   356
    ///
alpar@119
   357
    ///\sa halt()
alpar@119
   358
    ///\sa start()
alpar@119
   359
    ///\sa restart()
alpar@119
   360
    ///\sa reset()
alpar@119
   361
alpar@209
   362
    void stop()
alpar@119
   363
    {
alpar@119
   364
      if(_running && !--_running) {
alpar@209
   365
        TimeStamp t;
alpar@209
   366
        t.stamp();
alpar@209
   367
        start_time=t-start_time;
alpar@119
   368
      }
alpar@119
   369
    }
alpar@119
   370
alpar@119
   371
    ///Halt (i.e stop immediately) the time counters
alpar@119
   372
alpar@120
   373
    ///This function stops immediately the time counters, i.e. <tt>t.halt()</tt>
alpar@119
   374
    ///is a faster
alpar@119
   375
    ///equivalent of the following.
alpar@119
   376
    ///\code
alpar@119
   377
    ///  while(t.running()) t.stop()
alpar@119
   378
    ///\endcode
alpar@119
   379
    ///
alpar@119
   380
    ///
alpar@119
   381
    ///\sa stop()
alpar@119
   382
    ///\sa restart()
alpar@119
   383
    ///\sa reset()
alpar@119
   384
alpar@209
   385
    void halt()
alpar@119
   386
    {
alpar@119
   387
      if(_running) {
alpar@209
   388
        _running=0;
alpar@209
   389
        TimeStamp t;
alpar@209
   390
        t.stamp();
alpar@209
   391
        start_time=t-start_time;
alpar@119
   392
      }
alpar@119
   393
    }
alpar@119
   394
alpar@119
   395
    ///Returns the running state of the timer
alpar@119
   396
alpar@119
   397
    ///This function returns the number of stop() exections that is
alpar@119
   398
    ///necessary to really stop the timer.
alpar@119
   399
    ///For example the timer
alpar@119
   400
    ///is running if and only if the return value is \c true
alpar@119
   401
    ///(i.e. greater than
alpar@119
   402
    ///zero).
alpar@119
   403
    int running()  { return _running; }
alpar@209
   404
alpar@209
   405
alpar@119
   406
    ///Restart the time counters
alpar@119
   407
alpar@119
   408
    ///This function is a shorthand for
alpar@119
   409
    ///a reset() and a start() calls.
alpar@119
   410
    ///
alpar@209
   411
    void restart()
alpar@119
   412
    {
alpar@119
   413
      reset();
alpar@119
   414
      start();
alpar@119
   415
    }
alpar@209
   416
alpar@119
   417
    ///@}
alpar@119
   418
alpar@119
   419
    ///\name Query Functions for the ellapsed time
alpar@119
   420
alpar@119
   421
    ///@{
alpar@119
   422
alpar@119
   423
    ///Gives back the ellapsed user time of the process
alpar@119
   424
    double userTime() const
alpar@119
   425
    {
alpar@119
   426
      return operator TimeStamp().userTime();
alpar@119
   427
    }
alpar@119
   428
    ///Gives back the ellapsed system time of the process
alpar@119
   429
    double systemTime() const
alpar@119
   430
    {
alpar@119
   431
      return operator TimeStamp().systemTime();
alpar@119
   432
    }
alpar@119
   433
    ///Gives back the ellapsed user time of the process' children
deba@126
   434
alpar@209
   435
    ///\note On <tt>WIN32</tt> platform this value is not calculated.
deba@126
   436
    ///
alpar@119
   437
    double cUserTime() const
alpar@119
   438
    {
alpar@119
   439
      return operator TimeStamp().cUserTime();
alpar@119
   440
    }
alpar@119
   441
    ///Gives back the ellapsed user time of the process' children
deba@126
   442
alpar@209
   443
    ///\note On <tt>WIN32</tt> platform this value is not calculated.
deba@126
   444
    ///
alpar@119
   445
    double cSystemTime() const
alpar@119
   446
    {
alpar@119
   447
      return operator TimeStamp().cSystemTime();
alpar@119
   448
    }
alpar@119
   449
    ///Gives back the ellapsed real time
alpar@119
   450
    double realTime() const
alpar@119
   451
    {
alpar@119
   452
      return operator TimeStamp().realTime();
alpar@119
   453
    }
alpar@119
   454
    ///Computes the ellapsed time
alpar@119
   455
alpar@119
   456
    ///This conversion computes the ellapsed time, therefore you can print
alpar@119
   457
    ///the ellapsed time like this.
alpar@119
   458
    ///\code
alpar@119
   459
    ///  Timer t;
alpar@119
   460
    ///  doSomething();
alpar@119
   461
    ///  std::cout << t << '\n';
alpar@119
   462
    ///\endcode
alpar@119
   463
    operator TimeStamp () const
alpar@119
   464
    {
alpar@119
   465
      TimeStamp t;
alpar@119
   466
      t.stamp();
alpar@119
   467
      return _running?t-start_time:start_time;
alpar@119
   468
    }
alpar@119
   469
alpar@119
   470
alpar@119
   471
    ///@}
alpar@119
   472
  };
alpar@119
   473
kpeter@313
   474
  ///Same as Timer but prints a report on destruction.
alpar@119
   475
alpar@119
   476
  ///Same as \ref Timer but prints a report on destruction.
alpar@119
   477
  ///This example shows its usage.
alpar@119
   478
  ///\code
alpar@119
   479
  ///  void myAlg(ListGraph &g,int n)
alpar@119
   480
  ///  {
alpar@119
   481
  ///    TimeReport tr("Running time of myAlg: ");
alpar@119
   482
  ///    ... //Here comes the algorithm
alpar@119
   483
  ///  }
alpar@119
   484
  ///\endcode
alpar@119
   485
  ///
alpar@119
   486
  ///\sa Timer
alpar@119
   487
  ///\sa NoTimeReport
alpar@209
   488
  class TimeReport : public Timer
alpar@119
   489
  {
alpar@119
   490
    std::string _title;
alpar@119
   491
    std::ostream &_os;
alpar@119
   492
  public:
kpeter@313
   493
    ///Constructor
alpar@119
   494
kpeter@313
   495
    ///Constructor.
alpar@119
   496
    ///\param title This text will be printed before the ellapsed time.
alpar@119
   497
    ///\param os The stream to print the report to.
alpar@119
   498
    ///\param run Sets whether the timer should start immediately.
alpar@209
   499
    TimeReport(std::string title,std::ostream &os=std::cerr,bool run=true)
alpar@119
   500
      : Timer(run), _title(title), _os(os){}
kpeter@313
   501
    ///Destructor that prints the ellapsed time
alpar@209
   502
    ~TimeReport()
alpar@119
   503
    {
alpar@119
   504
      _os << _title << *this << std::endl;
alpar@119
   505
    }
alpar@119
   506
  };
alpar@209
   507
kpeter@313
   508
  ///'Do nothing' version of TimeReport
alpar@119
   509
alpar@119
   510
  ///\sa TimeReport
alpar@119
   511
  ///
alpar@119
   512
  class NoTimeReport
alpar@119
   513
  {
alpar@119
   514
  public:
alpar@119
   515
    ///\e
alpar@119
   516
    NoTimeReport(std::string,std::ostream &,bool) {}
alpar@119
   517
    ///\e
alpar@119
   518
    NoTimeReport(std::string,std::ostream &) {}
alpar@119
   519
    ///\e
alpar@119
   520
    NoTimeReport(std::string) {}
alpar@119
   521
    ///\e Do nothing.
alpar@119
   522
    ~NoTimeReport() {}
alpar@119
   523
alpar@119
   524
    operator TimeStamp () const { return TimeStamp(); }
alpar@119
   525
    void reset() {}
alpar@119
   526
    void start() {}
alpar@119
   527
    void stop() {}
alpar@209
   528
    void halt() {}
alpar@119
   529
    int running() { return 0; }
alpar@119
   530
    void restart() {}
alpar@119
   531
    double userTime() const { return 0; }
alpar@119
   532
    double systemTime() const { return 0; }
alpar@119
   533
    double cUserTime() const { return 0; }
alpar@119
   534
    double cSystemTime() const { return 0; }
alpar@119
   535
    double realTime() const { return 0; }
alpar@119
   536
  };
alpar@209
   537
alpar@119
   538
  ///Tool to measure the running time more exactly.
alpar@209
   539
alpar@119
   540
  ///This function calls \c f several times and returns the average
alpar@119
   541
  ///running time. The number of the executions will be choosen in such a way
alpar@119
   542
  ///that the full real running time will be roughly between \c min_time
alpar@119
   543
  ///and <tt>2*min_time</tt>.
alpar@119
   544
  ///\param f the function object to be measured.
alpar@119
   545
  ///\param min_time the minimum total running time.
alpar@119
   546
  ///\retval num if it is not \c NULL, then the actual
alpar@119
   547
  ///        number of execution of \c f will be written into <tt>*num</tt>.
alpar@119
   548
  ///\retval full_time if it is not \c NULL, then the actual
alpar@119
   549
  ///        total running time will be written into <tt>*full_time</tt>.
alpar@119
   550
  ///\return The average running time of \c f.
alpar@209
   551
alpar@119
   552
  template<class F>
alpar@119
   553
  TimeStamp runningTimeTest(F f,double min_time=10,unsigned int *num = NULL,
alpar@119
   554
                            TimeStamp *full_time=NULL)
alpar@119
   555
  {
alpar@119
   556
    TimeStamp full;
alpar@119
   557
    unsigned int total=0;
alpar@119
   558
    Timer t;
alpar@119
   559
    for(unsigned int tn=1;tn <= 1U<<31 && full.realTime()<=min_time; tn*=2) {
alpar@119
   560
      for(;total<tn;total++) f();
alpar@119
   561
      full=t;
alpar@119
   562
    }
alpar@119
   563
    if(num) *num=total;
alpar@119
   564
    if(full_time) *full_time=full;
alpar@119
   565
    return full/total;
alpar@119
   566
  }
alpar@209
   567
alpar@209
   568
  /// @}
alpar@119
   569
alpar@119
   570
alpar@119
   571
} //namespace lemon
alpar@119
   572
alpar@119
   573
#endif //LEMON_TIME_MEASURE_H