[gmx-developers] different energies with different compilers in implicit solvent

[Servaas Michielssens]

Hi,

I noticed a problem with the implicit solvent model but I am not
sure if it is related to the compiler issues that were
previously discussed on the list. I get different energies with
different compilers. I  use a git version I pulled yesterday.
I get an energy that looks correct with (-299.814087kj/mol):
gcc version 4.3.2 (on ubuntu)
icc Version 11.1 (SUSE)
But different energies with(-583.496033kj/mol):
gcc version 3.4.6 (SUSE)
gcc version 4.1.2 (SUSE)
With all of them I compile using single precision and without any MPI options (./configure --without-x).
If needed you can always send me an email to provide you with my input files, I failed to attach them in a mail to the list. 
It should be noted that in vacuum I get the same energies with all compilers.

These are the warnings
I get with gcc version 3.4.6  (no warnings with icc compiler, or gcc version 4.3.2)
checkpoint.c: In function ‘read_checkpoint_simulation_part’:
checkpoint.c:1932: warning: implicit declaration of function ‘upstring’
statutil.c: In function ‘parse_common_args’:
statutil.c:254: warning: ‘i’ may be used uninitialized in this function
statutil.c:255: warning: ‘select’ may be used uninitialized in this function
genborn.c: In function ‘table_log’:
genborn.c:183: warning: dereferencing type-punned pointer will break
strict-aliasing rules
pppm.c: In function ‘convolution’:
pppm.c:389: warning: dereferencing type-punned pointer will break
strict-aliasing rules
pme.c: In function ‘solve_pme’:
pme.c:1015: warning: dereferencing type-punned pointer will break
strict-aliasing rules

kind
regards,

servaas