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<TITLE>PetscGetCPUTime</TITLE>
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<div id="version" align=right><b>petsc-3.14.5 2021-03-03</b></div>
<div id="bugreport" align=right><a href="mailto:petsc-maint@mcs.anl.gov?subject=Typo or Error in Documentation &body=Please describe the typo or error in the documentation: petsc-3.14.5 v3.14.5 docs/manualpages/Sys/PetscGetCPUTime.html "><small>Report Typos and Errors</small></a></div>
<A NAME="PetscGetCPUTime"><H1>PetscGetCPUTime</H1></A>
Returns the CPU time in seconds used by the process.
<H3><FONT COLOR="#CC3333">Synopsis</FONT></H3>
<PRE>
#include "petscsys.h"
#include "petsctime.h"
<A HREF="../Sys/PetscErrorCode.html#PetscErrorCode">PetscErrorCode</A> <A HREF="../Sys/PetscGetCPUTime.html#PetscGetCPUTime">PetscGetCPUTime</A>(<A HREF="../Sys/PetscLogDouble.html#PetscLogDouble">PetscLogDouble</A> *t)
</PRE>
Not Collective
<P>
<H3><FONT COLOR="#CC3333">Output Parameter</FONT></H3>
<TABLE border="0" cellpadding="0" cellspacing="0">
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>t </B></TD><TD>- Time in seconds charged to the process.
</TD></TR></TABLE>
<P>
<H3><FONT COLOR="#CC3333">Example</FONT></H3>
<PRE>
#include <petscsys.h>
...
<A HREF="../Sys/PetscLogDouble.html#PetscLogDouble">PetscLogDouble</A> t1, t2;
ierr = <A HREF="../Sys/PetscGetCPUTime.html#PetscGetCPUTime">PetscGetCPUTime</A>(&t1);<A HREF="../Sys/CHKERRQ.html#CHKERRQ">CHKERRQ</A>(ierr);
... code to time ...
ierr = <A HREF="../Sys/PetscGetCPUTime.html#PetscGetCPUTime">PetscGetCPUTime</A>(&t2);<A HREF="../Sys/CHKERRQ.html#CHKERRQ">CHKERRQ</A>(ierr);
printf("Code took %f CPU seconds\n", t2-t1);
</PRE>
<P>
<P>
<H3><FONT COLOR="#CC3333">Notes</FONT></H3>
One should use <A HREF="../Sys/PetscTime.html#PetscTime">PetscTime</A>() or the -log_view option of
PETSc for profiling. The CPU time is NOT a realistic number to
use since it does not include the time for message passing etc.
Also on many systems the accuracy is only on the order of microseconds.
<P><B></B><H3><FONT COLOR="#CC3333">Level</FONT></H3>intermediate<BR>
<H3><FONT COLOR="#CC3333">Location</FONT></H3>
</B><A HREF="../../../src/sys/time/cputime.c.html#PetscGetCPUTime">src/sys/time/cputime.c</A>
<BR><A HREF="./index.html">Index of all Sys routines</A>
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