On Wed, 2007-08-29 at 11:36 -0400, Terry D. Dontje wrote:
> To run the code I usually do "mpirun -np 6 a.out 10" on a 2 core 
> system.  It'll print out the following and then hang:
> Target duration (seconds):         10.000000
> # of messages sent in that time:      589207
> Microseconds per message:             16.972
> 


I know almost nothing about FORTRAN but the stack dump told me
it got NULL pointer reference when accessing the "me" variable
in the do .. while loop. How can this happen?

[ollie@exponential ~]$ mpirun -np 2 a.out 100
[exponential:22145] *** Process received signal ***
[exponential:22145] Signal: Segmentation fault (11)
[exponential:22145] Signal code: Address not mapped (1)
[exponential:22145] Failing at address: (nil)
[exponential:22145] [ 0] [0xb7f2a440]
[exponential:22145] [ 1] a.out(MAIN__+0x54a) [0x804909e]
[exponential:22145] [ 2] a.out(main+0x27) [0x8049127]
[exponential:22145] [ 3] /lib/libc.so.6(__libc_start_main+0xe0)
[0x4e75ef70]
[exponential:22145] [ 4] a.out [0x8048aa1]
[exponential:22145] *** End of error message ***

            call MPI_Send(keep_going,1,MPI_LOGICAL,me+1,1,
     $           MPI_COMM_WORLD,ier)
 804909e:       8b 45 d4                mov    0xffffffd4(%ebp),%eax
 80490a1:       83 c0 01                add    $0x1,%eax

It is compiled with g77/g90.

Ollie


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