fortran - Reading multiple files in parallel and storing them in shared variables -
i have program reads number of large files (~100s files, 120mb each) generated mpi program, can take time. each file contains variables in corresponding subdomain. want read in variables files , store them specific slice of 4 dimensional array. since takes considerable amount of time, parallelize piece of code openmp:
6 subroutine read_old_restart 7 integer :: ii 8 integer :: thread_id 9 integer :: omp_get_thread_num 10 character(len=21) :: file_name 11 12 !$omp parallel private(ii,file_name) 13 ii=0,nproc_old-1 14 if(ii < 10) 15 write(file_name,401) "input/restart_00", ii, ".out" 16 else if(ii < 100) 17 write(file_name,402) "input/restart_0" , ii, ".out" 18 else 19 write(file_name,403) "input/restart_" , ii, ".out" 20 end if 21 print*, "thread = ", omp_get_thread_num(), "reading ", file_name 22 401 format(a16,i1,a4) 23 402 format(a15,i2,a4) 24 403 format(a14,i3,a4) 25 open (unit=321, file=trim(file_name), status="old", form="unformatted") 26 read(321) t , & 27 old_u (:,:,:,ii), & 28 old_v (:,:,:,ii), & 29 old_w (:,:,:,ii), & 30 old_p (:,:,:,ii), & 31 old_uc (:,:,:,ii), & 32 old_vc (:,:,:,ii), & 33 old_wc (:,:,:,ii), & 34 old_un2 (:,:,:,ii), & 35 old_vn2 (:,:,:,ii), & 36 old_wn2 (:,:,:,ii), & 37 old_un1 (:,:,:,ii), & 38 old_vn1 (:,:,:,ii), & 39 old_wn1 (:,:,:,ii), & 40 old_p1 (:,:,:,ii), & 41 old_viscu (:,:,:,ii), & 42 old_viscv (:,:,:,ii), & 43 old_viscw (:,:,:,ii), & 44 old_convu (:,:,:,ii), & 45 old_convv (:,:,:,ii), & 46 old_convw (:,:,:,ii), & 47 statindex , & 48 old_umn (:,:,:,ii), & 49 old_uumn (:,:,:,ii), & 50 old_urms (:,:,:,ii), & 51 old_mass_frac (:,:,:,:,:,ii), & 52 old_entht (:,:,:,:,ii) 53 close (321) 54 end 55 !$omp end parallel 56 end subroutine read_old_restart the code compiles , runs fine first loop of each thread. here output:
thread = 3 reading input/restart_030.out thread = 7 reading input/restart_067.out thread = 2 reading input/restart_020.out thread = 6 reading input/restart_058.out thread = 9 reading input/restart_085.out thread = 8 reading input/restart_076.out thread = 5 reading input/restart_049.out thread = 4 reading input/restart_040.out thread = 11 reading input/restart_103.out thread = 0 reading input/restart_000.out thread = 1 reading input/restart_010.out thread = 10 reading input/restart_094.out the code appears running , gets stuck on above output. when running top, cannot cpu usage. idea why not working expected?
you should use private integer variable unit number , set different value each thread. using same file unit differently different threads recipe trouble. quite surprised not crash.
Comments
Post a Comment