smash::Clock Class Reference

#include <clock.h>

Clock tracks the time in the simulation.

The basic unit is 1 fm in natural units which correspond to \(\frac{10^{-15}}{299\,792\,458}\,\mathrm{s} \approx 0.33\cdot10^{-23}\,\mathrm{s}\) in the international system of units. The resolution of the clock is \(0.000001\,\mathrm{fm}=10^{-6}\,\mathrm{fm}\), i.e. only multiples of \(0.000001\,\mathrm{fm}\) are internally representable.

Potential usage for adapting time steps:

UniformClock labtime(0., 0.1, end_time_);
UniformClock endtime(10., 0., end_time_);
while (labtime < endtime) {
  // do something
  // adapt the timestep size to external circumstances:
  if (system_is_very_dense()) {
    labtime.set_timestep_duration(labtime.timestep_duration() / 2.);
  }
  if (system_is_very_dilute()) {
    labtime.set_timestep_duration(labtime.timestep_duration() * 2.);
  }
  // let the clock tick
  ++labtime;
}

Possible actions for Clock are:

• look at it and find out the current time

  See also

  current_time()

  next_time()

• advance the clock (by one tick, by several ticks, or by a given time)

  See also

  operator++()

  operator+=(T)

  operator+=(Representation)

• set / retrieve the timestep (length of one tick)

  See also

  set_timestep_duration()

  timestep_duration()

• compare time against different clock or fixed value

  See also

  operator<(const Clock&) const

  operator<(float) const

  operator>(float) const

Definition at line 73 of file clock.h.

Inheritance diagram for smash::Clock:

Public Types
using	Representation = std::int64_t
	The type used for counting ticks/time. More...

Public Member Functions
virtual double	timestep_duration () const =0
virtual double	current_time () const =0
virtual double	next_time () const =0
virtual void	reset (double start_time, const bool is_output_clock)=0
	reset the clock to the starting time of the simulation More...
virtual void	remove_times_in_past (double start_time)=0
	Remove output times before the starting time of the simulation if this is a custom clock. More...
Clock &	operator++ ()
	Advances the clock by one tick. More...
Clock &	operator+= (Representation advance_several_timesteps)
	Advances the clock by an arbitrary number of ticks. More...
bool	operator< (const Clock &rhs) const
	Compares the times between two clocks. More...
bool	operator< (double time) const
	Compares the time of the clock against a fixed time. More...
bool	operator> (double time) const
	Compares the time of the clock against a fixed time. More...
virtual	~Clock ()=default

Protected Attributes
Representation	counter_ = 0
	Internally used to count the number of time steps. More...

Member Typedef Documentation

Representation

using smash::Clock::Representation = std::int64_t

The type used for counting ticks/time.

Definition at line 76 of file clock.h.

Constructor & Destructor Documentation

~Clock()

virtual smash::Clock::~Clock ( )

virtualdefault

Member Function Documentation

timestep_duration()

virtual double smash::Clock::timestep_duration ( ) const

pure virtual

Returns

the duration of the current time step

Implemented in smash::CustomClock, and smash::UniformClock.

current_time()

virtual double smash::Clock::current_time ( ) const

pure virtual

Returns

the current time

Implemented in smash::CustomClock, and smash::UniformClock.

next_time()

virtual double smash::Clock::next_time ( ) const

pure virtual

Returns

the time of the next time step

Implemented in smash::CustomClock, and smash::UniformClock.

reset()

virtual void smash::Clock::reset ( double  start_time, const bool  is_output_clock  )

pure virtual

reset the clock to the starting time of the simulation

Parameters

[in]	start_time	starting time of the imulation
[in]	is_output_clock	whether this is an output clock rather than a lab clock

Implemented in smash::CustomClock, and smash::UniformClock.

remove_times_in_past()

virtual void smash::Clock::remove_times_in_past ( double  start_time )

pure virtual

Remove output times before the starting time of the simulation if this is a custom clock.

Parameters

[in]

start_time

starting time of the simulation

Implemented in smash::UniformClock, and smash::CustomClock.

operator++()

Clock& smash::Clock::operator++ ( )

inline

Advances the clock by one tick.

This operator is used as ++clock. The operator clock++ is not implemented deliberately, because that requires a copy of the clock being created.

Definition at line 106 of file clock.h.

                      {
    // guard against overflow:
    if (counter_ >= std::numeric_limits<Representation>::max() - 1) {
      throw std::overflow_error("Too many timesteps, clock overflow imminent");
    }
    ++counter_;
    return *this;
  }

operator+=()

Clock& smash::Clock::operator+= ( Representation  advance_several_timesteps )

inline

Advances the clock by an arbitrary number of ticks.

Parameters

[in]

advance_several_timesteps

Number of the timesteps added to the clock

Exceptions

OverflowError

if the number of the added timesteps exceeds the maximum value.

Definition at line 123 of file clock.h.

                                                              {
    if (counter_ >= std::numeric_limits<Representation>::max() -
                        advance_several_timesteps) {
      throw std::overflow_error("Too many timesteps, clock overflow imminent");
    }
    counter_ += advance_several_timesteps;
    return *this;
  }

operator<() [1/2]

bool smash::Clock::operator< ( const Clock &  rhs ) const

inline

Compares the times between two clocks.

Parameters

[in]

rhs

The other clock.

Definition at line 137 of file clock.h.

                                         {
    return current_time() < rhs.current_time();
  }

operator<() [2/2]

bool smash::Clock::operator< ( double  time ) const

inline

Compares the time of the clock against a fixed time.

Parameters

[in]

time

The other time.

Definition at line 146 of file clock.h.

{ return current_time() < time; }

operator>()

bool smash::Clock::operator> ( double  time ) const

inline

Compares the time of the clock against a fixed time.

Parameters

[in]

time

The other time.

Definition at line 153 of file clock.h.

{ return current_time() > time; }

Member Data Documentation

counter_

Representation smash::Clock::counter_ = 0

protected

Internally used to count the number of time steps.

Definition at line 161 of file clock.h.

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The documentation for this class was generated from the following file:

• src/include/smash/clock.h