fortime – ForTime

fortime provides the timer derived type plus the public real kind rk and integer kind ik. A single timer object can measure several kinds of elapsed time:

timer_start / timer_stop use the intrinsic system_clock.
ctimer_start / ctimer_stop use the intrinsic cpu_time.
dtimer_start / dtimer_stop use the intrinsic date_and_time.
otimer_start / otimer_stop use omp_get_wtime when USE_OMP is defined.
mtimer_start / mtimer_stop use MPI_Wtime when USE_MPI is defined.

The usual workflow is to call a start routine, execute the code being timed, call the matching stop routine, and then read the matching public result component. Stop routines can also print the elapsed time, average it over a positive loop count, and customize the output label, color, and real format.

Basic usage:

use fortime, only: timer
type(timer) :: t

call t%timer_start()
call work()
call t%timer_stop(print=.false.)
print *, t%elapsed_time

Loop-averaged usage:

call t%timer_start()
do i = 1, nloops
   call work()
end do
call t%timer_stop(nloops=nloops, message='Average time:', print=.true.)

Note

The system_clock, OpenMP, and MPI timers are the preferred wall-clock timers. The date_and_time timer is a civil-clock fallback and is not guaranteed to be monotonic.

Uses

- iso_fortran_env
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Used by

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Graph Key

Nodes of different colours represent the following:

Solid arrows point from a submodule to the (sub)module which it is descended from. Dashed arrows point from a module or program unit to modules which it uses.
Where possible, edges connecting nodes are given different colours to make them easier to distinguish in large graphs.

Variables

Type	Visibility	Attributes		Name		Initial
integer,	public,	parameter	::	ik	=	int64	Integer kind used by the internal tick counters and civil-date calculations. It is currently mapped to `int64`.
integer,	public,	parameter	::	rk	=	real64	Real kind used by the public timing results and internal real-valued calculations. It is currently mapped to `real64`.

Derived Types

type, public :: timer

Timing object with independent state for each supported backend.

Type	Visibility		Name		Initial
real(kind=rk),	public	::	cpu_time	=	0.0_rk	Most recent successful CPU-time measurement in seconds.
real(kind=rk),	public	::	elapsed_dtime	=	0.0_rk	Most recent successful `date_and_time` elapsed time in seconds.
real(kind=rk),	public	::	elapsed_time	=	0.0_rk	Most recent successful `system_clock` elapsed time in seconds.
integer(kind=ik),	private	::	clock_max	=	0_ik	Cached maximum `system_clock` count used to handle one counter wrap.
integer(kind=ik),	private	::	clock_rate	=	0_ik	Cached `system_clock` count rate in ticks per second.
integer(kind=ik),	private	::	clock_start	=	0_ik	`system_clock` count captured at the start of the wall-clock interval.
real(kind=rk),	private	::	cpu_start	=	0.0_rk	CPU time, in seconds, captured by `ctimer_start`.
real(kind=rk),	private	::	dtime_start_utc	=	0.0_rk	UTC epoch seconds computed from `date_and_time` at `dtimer_start`.
logical,	private	::	is_cpu_started	=	.false.	True after `ctimer_start` and before a successful `ctimer_stop`.
logical,	private	::	is_dtime_started	=	.false.	True after `dtimer_start` and before a successful `dtimer_stop`.
logical,	private	::	is_paused	=	.false.	True after `timer_pause` and before a matching `timer_resume`.
logical,	private	::	is_started	=	.false.	True after `timer_start` and before a successful `timer_stop`.
integer(kind=ik),	private	::	pause_start	=	0_ik	`system_clock` count captured when the wall-clock timer is paused.
integer(kind=ik),	private	::	paused_ticks	=	0_ik	Total paused duration, in `system_clock` ticks, excluded from the result.

procedure, public :: ctimer_start	Start a CPU-time measurement.
procedure, public :: ctimer_stop	Stop a CPU-time measurement and update `cpu_time`.
procedure, public :: ctimer_write	Append `cpu_time` to a text file.
procedure, public :: dtimer_start	Start a `date_and_time` civil-clock measurement.
procedure, public :: dtimer_stop	Stop a `date_and_time` civil-clock measurement and update `elapsed_dtime`.
procedure, public :: dtimer_write	Append `elapsed_dtime` to a text file.
procedure, public :: timer_pause	Pause a running `system_clock` wall-clock measurement.
procedure, public :: timer_resume	Resume a paused `system_clock` wall-clock measurement.
procedure, public :: timer_start	Start a `system_clock` wall-clock measurement.
procedure, public :: timer_stop	Stop a `system_clock` wall-clock measurement and update `elapsed_time`.
procedure, public :: timer_write	Append `elapsed_time` to a text file.

Type	Intent		Name
integer(kind=ik),	intent(in)	::	y	Civil year in the proleptic Gregorian calendar.
integer(kind=ik),	intent(in)	::	m	Civil month in the range 1 to 12.
integer(kind=ik),	intent(in)	::	d	Civil day of month.

Type	Intent		Name
integer(kind=ik),	intent(in)	::	t_end	End tick captured from `system_clock`.
integer(kind=ik),	intent(in)	::	t_start	Start tick captured from `system_clock`.
integer(kind=ik),	intent(in)	::	t_max	Maximum count returned by `system_clock`; non-positive means unknown.

Type	Intent	Optional		Name
class(timer),	intent(inout)		::	this	Timer instance previously started with `ctimer_start`.
integer,	intent(in),	optional	::	nloops	Optional positive loop count used to compute average CPU time.
character(len=*),	intent(in),	optional	::	message	Optional output label; defaults to `CPU time:`.
logical,	intent(in),	optional	::	print	Optional output switch; defaults to `.true.`.
character(len=*),	intent(in),	optional	::	color	Optional FACE foreground color used for printed output.
character(len=*),	intent(in),	optional	::	rfmt	Optional Fortran real edit descriptor used for printed output.

Type	Intent	Optional		Name
real(kind=rk),	intent(in)		::	value_raw	Raw measured duration in seconds.
integer,	intent(in),	optional	::	nloops	Optional positive loop count used to compute an average time per loop.
real(kind=rk),	intent(out)		::	value_out	Validated duration in seconds, averaged by `nloops` when present.
character(len=*),	intent(in)		::	default_label	Backend-specific output label used when `message` is absent.
character(len=*),	intent(in),	optional	::	message	Optional output label printed before the timing value.
logical,	intent(in),	optional	::	print	Optional output switch; defaults to `.true.`.
character(len=*),	intent(in),	optional	::	color	Optional FACE foreground color for the printed label and unit suffix.
character(len=*),	intent(in),	optional	::	rfmt	Optional Fortran real edit descriptor used by `print_time`.
logical,	intent(out)		::	ok	True when finalization succeeds and the caller may store `value_out`.

Type	Intent	Optional		Name
real(kind=rk),	intent(in)		::	time	Timing value in seconds.
character(len=*),	intent(in)		::	message	Label printed before `time`.
character(len=*),	intent(in),	optional	::	color	Optional FACE foreground color; defaults to `blue`.
character(len=*),	intent(in),	optional	::	rfmt	Optional Fortran real edit descriptor; defaults to `F16.9`.
logical,	intent(out)		::	ok	True when the formatted write completed successfully.

fortime Module

Contents

Variables

Derived Types

Functions

Subroutines

Uses

Used by

Variables

Derived Types

type, public :: timer

Components

Type-Bound Procedures

Functions

private pure function days_from_civil(y, m, d) result(days)

Arguments

Return Value integer(kind=ik)

private pure function epoch_seconds_utc(values) result(t)

Arguments

Return Value real(kind=rk)

private pure function ticks_diff(t_end, t_start, t_max) result(dt)

Arguments

Return Value integer(kind=ik)

Subroutines

private subroutine ctimer_start(this)

Arguments

private subroutine ctimer_stop(this, nloops, message, print, color, rfmt)

Arguments

private subroutine ctimer_write(this, file_name)

Arguments

private subroutine dtimer_start(this)

Arguments

private subroutine dtimer_stop(this, nloops, message, print, color, rfmt)

Arguments

private subroutine dtimer_write(this, file_name)

Arguments

private subroutine finalize_timing(value_raw, nloops, value_out, default_label, message, print, color, rfmt, ok)

Arguments

private subroutine print_time(time, message, color, rfmt, ok)

Arguments

private subroutine timer_pause(this)

Arguments

private subroutine timer_resume(this)

Arguments

private subroutine timer_start(this)

Arguments

private subroutine timer_stop(this, nloops, message, print, color, rfmt)

Arguments

private subroutine timer_write(this, file_name)

Arguments

private subroutine write_to_file(time, file_name)

Arguments