RE: Re: DLOAD subroutine not working on parallel mode Yahoo / Sent

From the manual (Execution->Parallel Execution->About parallel execution->Use with user subroutines):

User subroutines can be used when running jobs in parallel. In a distributed run, the entire model is decomposed into separate domains (partitions). Each domain is serviced by a separate MPI process. Abaqus provides well-defined synchronization points at which it is possible to exchange information across all MPI ranks, using the MPI communications facilities. All native MPI calls are supported, in both Fortran and C++. In addition, for cases of hybrid execution, user subroutines and any subroutines called by them must be thread safe. This precludes the use of common blocks, data statements, and save statements. To work around these limitations and for guidelines and techniques, see Ensuring thread safety<file:///C:/Program%20Files/Dassault%20Systemes/SIMULIA2018doc/English/SIMACAESUBRefMap/simasub-c-getthreadid.htm>.

Bottom line:  COMMON blocks can’t be used when running in parallel...

Regards,

Dave Lindeman
Staff Scientist
Corporate Research Systems Laboratory
3M Center 235-3G-08
St. Paul, MN 55144
651-733-6383

From: [email protected] <[email protected]>
Sent: Thursday, May 02, 2019 8:59 AM
To: [email protected]
Subject: [EXTERNAL] Re: [Abaqus] DLOAD subroutine not working on parallel mode Yahoo / Sent



I do not fully understand how the parallel execution works, but perhaps
you can read the data first into a common block and then access it from
there. However, I am nut sure how common blocks work in parallel
fortran.

There are auxilliary routines that can find out on which processor you
are - so if you do this only on one processor, the reading problem
should be circumvented.

You could also try to run in loop-parallelization although this might
be less efficient.

On 02 May 2019 10:23:54 +0000
"[email protected] [Abaqus]" <[email protected]> wrote:

> Dear All,
>
>
> I have written a DLOAD subroutine which will read Pressure on a surface from an external file and run a direct implicit transient analysis. The pressure on the surface elements will be read from respective files for each time step. I have checked this on my computer in serial mode for 100 elements and 5 time steps and it works fine.This is the same in parallel mode too. However, when I increase the number of elements in the file to 1000 and put it on parallel the simulations does not work. It compiles fine and starts running but it only reads a few elements and halts. There are no error messages and the status shows running but it is not actually. The same is the situation when I put it on cluster with 16 CPUs. I am not able to understand what the problem could be. It has something got to reading these files in parallel and checking the element number and mapping the pressure for each time step.
>
>
> I would really appreciate if someone could please help me or guide me regarding this.
>
>
> My DLOAD sub routine is below.
>
>
> SUBROUTINE DLOAD(P,KSTEP,KINC,TIME,NOEL,NPT,LAYER,KSPT,COORDS,
> 1 JLTYP,SNAME)
> C
> INCLUDE 'ABA_PARAM.INC'
> C
> DIMENSION TIME(2),COORDS(3)
> CHARACTER*80 SNAME
> PARAMETER (PLOAD1=1000)
> CHARACTER PRES*80
> INTEGER :: SUCCESS
> INTEGER :: K, L, M, ELNO, T, F, I, NN ! K is for the element number,L is word P and M is for pressure value
> REAL :: PLOAD
> CHARACTER (len=100) :: pname
> CHARACTER (len=30) :: loadfile
>
>
> DO I=1,5 ! NUMBER OF INCREMENTS
> IF (KINC.EQ.I) THEN
> WRITE (loadfile,'("output",I0,".inp")') I
> pname="C:\Users\lakshmp1\L1000\"//loadfile
> PRINT *,pname
> NN=100+I
> OPEN(UNIT=NN, FILE=pname, ACCESS='SEQUENTIAL', ACTION='READ')
> T=1
> DO T=1,1 ! skips the first line which is named as *DLOAD
> READ(NN,*)
> END DO
> DO
> READ(UNIT=NN, FMT='(A)', IOSTAT=SUCCESS, END=9)PRES
> IF (SUCCESS.NE.0) EXIT
>
>
> K=6
> DO WHILE (PRES(K:K) .NE. ',')
> K=K+1
> END DO
>
>
> READ(PRES(6:K-1), *) ELNO ! this variable stores the element number
> PRINT *, ELNO
>
> L=K+1
> DO WHILE (PRES(L:L) .NE. ',')
> L=L+1
> END DO
>
>
>
> M=L+1
> DO WHILE (PRES(M:M) .NE. ' ')
> M=M+1
> END DO
>
>
>
> READ(PRES(L+1:M-1), *) PLOAD ! this variable stores the pressure on that element
> PRINT *, PLOAD
> IF(NOEL.EQ.ELNO) THEN
> P=PLOAD
> PRINT *, 'PLOAD written'
> END IF
>
> END DO
> 9 CLOSE(NN)
> END IF
> END DO
> RETURN
> END
>
>
>
>
>
> Thank You.
>
>
> Arun

--
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Institut für Werkstoffe
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