[mpich-discuss] F90FLAGS "-i4" statement for mpich2 configuration

[Steenhauer, Kate]

Hello,

My mpich2 was configured as follows

[eng923 at cops-021026 job]$ mpich2version
MPICH2 Version:         1.2.1p1
MPICH2 Release date:    Unknown, built on Mon Mar 29 14:37:13 BST 2010
MPICH2 Device:          ch3:nemesis
MPICH2 configure:       --prefix=/opt/mpich2
MPICH2 CC:      gcc  -O2
MPICH2 CXX:     c++  -O2
MPICH2 F77:     gfortran  -O2
MPICH2 F90:     f95  -O2

When I read the following (see below) in migrating from mpich1 to mpich2, is this possibly causding the problem in mpi_scatter? As I am using an Intel fortran compiler on a 64 bit linux platform? Would I need to reinstall and configure MPIch2 and where and how do I include the F90FLAGS "-i4" statement on a bash Shell?

D.4 Q: When I use the g95 Fortran compiler on a 64-bit
platform, some of the tests fail
A: The g95 compiler incorrectly defines the default Fortran integer as a 64-
bit integer while defining Fortran reals as 32-bit values (the Fortran standard
requires that INTEGER and REAL be the same size). This was apparently
done to allow a Fortran INTEGER to hold the value of a pointer, rather
than requiring the programmer to select an INTEGER of a suitable KIND.
To force the g95 compiler to correctly implement the Fortran standard, use
the -i4 flag. For example, set the environment variable F90FLAGS before
configuring MPICH2:
setenv F90FLAGS "-i4"
G95 users should note that there (at this writing) are two distributions of
g95 for 64-bit Linux platforms. One uses 32-bit integers and reals (and
conforms to the Fortran standard) and one uses 32-bit integers and 64-bit
reals. We recommend using the one that conforms to the standard (note
that the standard specifies the ratio of sizes, not the absolute sizes, so a
Fortran 95 compiler that used 64 bits for both INTEGER and REAL would
also conform to the Fortran standard. However, such a compiler would need
to use 128 bits for DOUBLE PRECISION quantities).

Thanks kate



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