lemon-0.x: comparison lemon/time

equal deleted inserted replaced

-:f6f2cbacd3a0
+:552a171eb2d2
 double real_time;
 rtms &getTms() {return ts;}
 const rtms &getTms() const {return ts;}
+void _reset()
+{ ts.tms_utime=ts.tms_stime=ts.tms_cutime=ts.tms_cstime=0; real_time=0;}
 public:
 ///Read the current time values of the process
 void stamp()
 {
 ts=_ts;
 }
 /// Constructor initializing with zero
 TimeStamp()
-{ ts.tms_utime=ts.tms_stime=ts.tms_cutime=ts.tms_cstime=0; real_time=0;}
+{ _reset(); }
 ///Constructor initializing with the current time values of the process
 TimeStamp(void *) { stamp();}
+///Set every time value to zero
+TimeStamp &reset() {_reset();return *this;}
 ///\e
 TimeStamp &operator+=(const TimeStamp &b)
 {
 ts.tms_utime+=b.ts.tms_utime;
 ts.tms_stime+=b.ts.tms_stime;
 {
 TimeStamp t(*this);
 return t-=b;
 }
 ///\e
-///\bug operator * and / gives rounded values!
 TimeStamp &operator*=(double b)
 {
 ts.tms_utime*=b;
 ts.tms_stime*=b;
 ts.tms_cutime*=b;
 ///Gives back the user time of the process' children
 double cSystemTime() const
 {
 return double(ts.tms_cstime)/sysconf(_SC_CLK_TCK);
 }
-///Gives back the real time of the process
+///Gives back the real time
 double realTime() const {return real_time;}
 };
 TimeStamp operator*(double b,const TimeStamp &t)
 {
 return t*b;
 }
-///Class measuring the cpu time and real time usage of the process
+///Class for measuring the cpu time and real time usage of the process
-///Class measuring the cpu time and real time usage of the process.
+///Class for measuring the cpu time and real time usage of the process.
 ///It is quite easy-to-use, here is a short example.
 ///\code
 ///#include<lemon/time_measure.h>
 ///#include<iostream>
 ///
 ///  ...
 ///
 ///}
 ///\endcode
 ///
+///The \ref Timer can also be \ref stop() "stopped" and
+///\ref start() "started" again, so it is easy to compute collected
+///running times.
+///
+///\warning Depending on the operation system and its actual configuration
+///the time counters have a certain (relatively big) granularity.
+///Therefore this tool is not appropriate to measure very short times.
+///Also, if you start and stop the timer very frequently, it could lead
+///distorted results.
+///
+///The \ref Timer also counts the number of \ref start()
+///executions, and is stops only after the same amount (or more)
+///\ref stop() "stop()"s. This can be useful e.g. to compute the running time
+///of recursive functions.
+///
 ///\todo This shouldn't be Unix (Linux) specific.
 ///
 ///\author Alpar Juttner
 class Timer
 {
-TimeStamp start_time;
+int running; //Timer is running iff running>0; (running>=0 always holds)
+TimeStamp start_time; //This is the relativ start-time if the timer
-void _reset() {start_time.stamp();}
+//is running, the collected running time otherwise.
+void _reset() {if(running) start_time.stamp(); else start_time.reset();}
 public:
-///Constructor. It starts with zero time counters
+///Constructor.
-Timer() {_reset();}
+///\param _running indicates whether or not the timer starts immediately.
+///
+Timer(bool _running=true) :running(_running) {_reset();}
 ///Computes the ellapsed time
 ///This conversion computes the ellapsed time
-///since the construction of \c t or since
+///
-///the last \c t.reset().
 operator TimeStamp () const
 {
 TimeStamp t;
 t.stamp();
-return t-start_time;
+return running?t-start_time:start_time;
 }
 ///Resets the time counters
 ///Resets the time counters
 void reset()
 {
 _reset();
 }
+///Start the time counters
+///This function starts the time counters.
+///
+///If the timer is started more than ones, it will remain running
+///until the same amount of \ref stop() is called.
+///\sa stop()
+void start()
+{
+if(running) running++;
+else {
+	TimeStamp t;
+	t.stamp();
+	start_time=t-start_time;
+}
+}
+///Stop the time counters
+///This function stops the time counters.
+///
+///\sa stop()
+void stop()
+{
+if(running && !--running) {
+	TimeStamp t;
+	t.stamp();
+	start_time=t-start_time;
+}
+}
 ///Gives back the ellapsed user time of the process
 double userTime() const
 {
 return operator TimeStamp().userTime();
 }
 ///Gives back the ellapsed user time of the process' children
 double cSystemTime() const
 {
 return operator TimeStamp().cSystemTime();
 }
-///Gives back the ellapsed real time of the process
+///Gives back the ellapsed real time
 double realTime() const
 {
 return operator TimeStamp().realTime();
 }
 ///Tool to measure the running time more exactly.
 ///This function calls \c f several times and returns the average
 ///running time. The number of the executions will be choosen in such a way
-///that the full running time will be roughly between \c min_time
+///that the full real running time will be roughly between \c min_time
 ///and <tt>2*min_time</tt>.
 ///\param f the function object to be measured.
 ///\param min_time the minimum total running time.
 ///\retval num if it is not \c NULL, then *num will contain the actual
 ///        number of execution of \c f.

changeset 1788	614ce2dd3cba
parent 1689	f1795dafe42c
child 1806	1530c115580f