how can I Measuring an Execution Time in fortran, f90, in a PC. Is there any command can I write in my code in order to see how many min, sec, hours that I need to get results.

thanx

You can use the "CALL CPU_TIME(..)" in a line. The usage can be found by googling.

is there any example on line? couldn't find any!

place "CALL CPU_TIME (time_begin)" at the very beginning of the code, and place "CALL CPU_TIME (time_end)" where you want to calculate the CPU time. So; time_spent = time_end - time_begin in seconds.

Many thanks for your reply. Consider the following code. Say the follwoing is user1.f90 (the main peogram)

PROGRAM test

USE SAMPLE

IMPLICIT NONE

save

DO I = 1,5

CALL CPU_TIME (time_begin)

K(I) = 2*I

time_spent = time_end - time_begin

CALL CPU_TIME (time_end)

print*, 'Time of operation was ', time_spent, ' seconds'

END DO

END PROGRAM test

------------:-

And I have a separate file called: SAMPLE.f90

--------:

MODULE SAMPLE

INTEGER, DIMENSION (10) :: K

INTEGER :: I

real :: time_spent, time_end, time_begin

END MODULE SAMPLE

--------------------

Am running this in a PC using a PC compiler (only no linux or unix)and it is not working at all for the use statement and not for the cpu time.

How can I solve this problem, am still new to fortran 95/90. is the USE done with unix ONLY ?

Thanks for your help.

.... REAL begin_time, end_time ...

CALL CPU_TIME(begin_time)

DO WHILE(t < tfinal)

...

ENDDO

CALL CPU_TIME(end_time)

PRINT*,' ' PRINT*,'total computing time: ',(end_time-begin_time),'sec.'

you can apply USE and CPU_TIME declarations in f90, your code should have worked. check out your compiler's help documents, it might apply slightly different declarations. also, put the cpu time built-in fuctions outside of the do-loop, unless you do want to measure the time for each and every iteration operation. and you should have calculated the time_spent after obtaining time_end.

The time is working now BUT not the use statement! Shall I switch to a different compiler? Or keep trying

cpu_time may vary i think, but use statement have to be a standard declaration for f90. perhaps you haven't added the module file to the project before compilation.

wait a moment, how can it works without the use statement? if cpu_time works then use statements must be working also. you are missing some point, it is better to examine details before asking i think.

working without the USE !

there is an "implicit none" statement in your main file, therefore every variable have to be declared beforehand. use statement or your module is working obviously. if you couldn't see the variables in debugging screen it is because they are global variables, and you can see the assigned values to them by writing down variable's names in debugging screen explicitly.