On Oct 1, 2003, at 10:02 AM, Olivier Paradis-Beland wrote:
> So, I enter the following command : [ ]$ mpif77 pi.f
> and lam gives me that error message :
>
> FORTRAN 77 Compiler 7.5a, Copyright (c) 1987-2002, Absoft Corp.
> pi.o: In function `main':
> pi.o(.text+0x59): undefined reference to `MPI_INIT'
> pi.o(.text+0x8a): undefined reference to `MPI_COMM_RANK'
> pi.o(.text+0xb6): undefined reference to `MPI_COMM_SIZE'
> pi.o(.text+0x325): undefined reference to `MPI_BCAST'
> pi.o(.text+0x4b9): undefined reference to `MPI_REDUCE'
> pi.o(.text+0x5ba): undefined reference to `MPI_FINALIZE'
> collect2: ld returned 1 exit status
This looks like a problem with linking in the Fortran library - the
linker is not able to find the expected symbols. All of the symbols
listed above are valid MPI symbols, so they really should be there. I
would suspect that LAM and the Fortran compiler are using different
name mangling schemes, resulting in LAM proving a symbol link
__mpi_init and Absoft mangled the symbol to MPI_INIT.
Did you compile LAM to use the Absoft Fortran compiler? As you used
mpif77 to compile your code, I'm assuming so. However, it is possible
to override which compiler LAM uses with the LAMF77 environment
variable. Mixing Fortran compilers is generally a bad idea - if LAM is
built with gcc (for example), then LAM applications should really be
built with gcc and not Absoft's compiler.
One other possible problem is Absoft-specific. The default mode of
Absoft's compiler is to be case-sensitive (so MPI_INIT and MPI_Init are
different symbols). Most Fortran compilers are not, so Absoft provides
a flag to be case insensitive. In doing so, the compiler changes its
name mangling scheme. I think the version of LAM you are using was
compiled with the special case-insensitive flag but your user
application was not. Hence, the missing symbols. I would check with
whomever compiled your installation of LAM - you need to use the same
flags to mpif77 that they provided for compiling the Fortran interface.
Hope this helps,
Brian
--
Brian Barrett
LAM/MPI developer and all around nice guy
Have a LAM/MPI day: http://www.lam-mpi.org/
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