#
wtime

**wtime**,
a MATLAB code which
returns a reading of the wall clock time.

For parallel programming, the important thing to measure is the elapsed
wallclock time. This can be found by subtracting an initial reading of
the wallclock time from a final one.

The OpenMP system provides a function used as follows:

seconds = omp_get_wtime ( )
operations to time;
seconds = omp_get_wtime ( ) - seconds;

while the MPI system provides a similar function used as:
seconds = MPI_Wtime ( );
operations;
seconds = MPI_Wtime ( ) - seconds;

and in MATLAB, wallclock time can be taken with "tic" and "toc":
tic;
operation;
seconds = toc;

WTIME provides a way to get a similar reading:

seconds = wtime ( );
operations;
seconds = wtime ( ) - seconds;

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Licensing:

The computer code and data files described and made available on this web page
are distributed under
the GNU LGPL license.

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Languages:

**wtime** is available in
a C version and
a C++ version and
a FORTRAN90 version and
a MATLAB version and
an Octave version and
a Python version.

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Related Data and Programs:

tic_toc_test,
MATLAB codes which
demonstrate tic() and toc() functions for wallclock timing.

timer_test,
a MATLAB code which
shows how to compute the elapsed CPU time inside a program.

timestamp,
a MATLAB code which
displays the current wall clock time.

wtime_test

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Source Code:

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Last revised on 16 May 2021.
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