From: Etienne ENGLER
Subject: Re: Gibbs with Linux RH 7.0
Date: Wed, 17 Jan 2001 10:43:47 +0100


An experimental solution to gibbs MPI/Linux :

1) To enable MPI

gib.f : lines 312-317

Replace
c --- for now, Aug 1997, disable MPI_gibbs, since it fails the
c dynamically modified windows test .... dac
c
write(6,*) 'MPI version of gibbs is currently disabled.'
call mexit(6,1)
c

with
c --- for now, Aug 1997, disable MPI_gibbs, since it fails the
c dynamically modified windows test .... dac
c
c write(6,*) 'MPI version of gibbs is currently disabled.'
c call mexit(6,1)
c


2) To avoid a locking (wait for other process reply)

gibb.f : lines 2372-2376

Replace
C If IFRC>0 then IMES was > 0 on call. In this case only wanted
C derivates, so return now.
C
IF (IFRC.GT.0) RETURN
C

with
C If IFRC>0 then IMES was > 0 on call. In this case only wanted
C derivates, so return now.
C
IF (IFRC.GT.0) then
#ifdef MPI
if (ICORC.eq.1) call cor_mpi_wait(epert,itcumx)
#endif
RETURN
endif
C


3) Add this routine (in machinedep.f for example) :

#ifdef MPI
subroutine cor_mpi_wait(epert,itcumx)
c
IMPLICIT DOUBLE PRECISION (A-H,O-Z)
# include "mpif.h"
DOUBLE PRECISION E58, E59, E60
COMMON/JMTE/E58, E59, E60
DIMENSION EPERT(*)
c
DO 10 ITERA=1,ITCUMX
ITER = ITERA
DO 20 IFRE = 1,2
IFR = IFRE
c
e58 = 0.
e59 = 0.
call mpi_reduce(EPERT(58),e58,1,
+ MPI_DOUBLE_PRECISION,MPI_SUM,0,MPI_COMM_WORLD,ierr)
call mpi_reduce(EPERT(59),e59,1,
+ MPI_DOUBLE_PRECISION,MPI_SUM,0,MPI_COMM_WORLD,ierr)
EPERT(58) = e58
EPERT(59) = e59
c
IF (ITER.EQ.1 .AND. IFR.EQ.1) THEN
e60 = 0.
call mpi_reduce(EPERT(60),e60,1,
+ MPI_DOUBLE_PRECISION,MPI_SUM,0,MPI_COMM_WORLD,ierr)
EPERT(60) = e60
END IF
20 continue
10 continue
c
end
#endif


Etienne Engler
MSM - UMR7551
ULP Strasbourg