MPIWtime(3OpenMPI) MPIWtime(3OpenMPI)

NAME
       MMPPIIWWttiimmee - Returns an elapsed time on the calling processor.


SSYYNNTTAAXX
CC SSyynnttaaxx
       #include 
       double MPIWtime()


FFoorrttrraann SSyynnttaaxx
       INCLUDE 'mpif.h'
       DOUBLE PRECISION MPIWTIME()


CC++++ SSyynnttaaxx
       #include 
       double Wtime()


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       Time in seconds since an arbitrary time in the past.


DESCRIPTION
       MPIWtime  returns  a  floating-point  number  of seconds, representing
       elapsed wall-clock time since some time in the past.

       The "time in the past" is guaranteed not to change during the  life  of
       the  process.  The  user is responsible for converting large numbers of
       seconds to other units if they are preferred.

       This function is portable (it returns seconds, not "ticks"), it  allows
       high  resolution,  and carries no unnecessary baggage. One would use it
       like this:

           {
              double starttime, endtime;
              starttime = MPIWtime();
               ....  stuff to be timed  ...
              endtime   = MPIWtime();
              printf("That took %f seconds\n",endtime-starttime);
           }

       The times returned are local to the node that called them. There is  no
       requirement that different nodes return the "same" time.

NNOOTTEESS
       The  boolean  variable  MPIWTIMEISGLOBAL, a predefined attribute key
       that indicates whether clocks are synchronized, does not have  a  valid
       value in Open MPI, as the clocks are not guaranteed to be synchronized.


       This is intended to be a high-resolution, elapsed (or wall) clock.  See
       MPIWtick to determine the resolution of MPIWtime.

       This  function does not return an error value. Consequently, the result
       of calling it before MPIInit or after MPIFinalize is undefined.


SEE ALSO
       MPIWtick




Open MPI 1.2                    September 2006             MPIWtime(3OpenMPI)