[gmx-users] Problem to run more than 2 NPT REMD replicas - 4

[David van der Spoel]

pascal.baillod at epfl.ch wrote:
> Hello David,
> 
> Thank you very much for your answer. I checked my repl_ex.c file, line 142 is
> exactly as what you sent me below, with a "<". I also tried inverting the ref_p
> order in my .mdp files, so that 
> 
>           temp   ref_p
> md0.mdp   300    1.0
> md1.mdp   302    1.0
> md2.mdp   304    0.5
> 
> After generating the respective .tpr files and starting replica exchange, I
> still get the same error message (which this time is what we expect it should
> be). Here is my job file, in case that could help:
> 
> wipe
> lamboot hostfile
>  
> mpirun -np 3 /Software/usr/gromacs-3.3.0/icc9.0_lam7.1.1/bin/mdrun_mpi -multi
> -np 3 -s md.tpr -replex 2000 -reseed -1

Very weird indeed. Could you (with the original tpr files) try without 
the -multi flag?
Also, did you succeed with identical pressures?

It could be a compiler problem, the Intel compiler warns all the time 
that comparisons between floating point numbers are not exact.

> 
> Thank you very much!
> 
> Pascal
> 
> 
> 
> 
> 
>>It seems that your pressure*increases* with increasing temperature.
>>Check line 141 in src/kernel/repl_ex.c
>>it should read:
>>
>>    if ((i > 0) && (re->pres[re->ind[i]] < re->pres[re->ind[i-1]]))
>>      gmx_fatal(FARGS,"The reference pressure decreases with increasing
>>
>>temperature");
>>
>>Check whether you have < or >
>>
> 
> *******************************************************************************
> Pascal Baillod (PhD student) 
> *******************************************************************************
> Swiss Federal Institute of Technology EPFL	        Tel: +41-(0)21-693-0322
> Institute of Chemical Sciences and Engineering ,	Fax: +41-(0)21-693-0320
> Laboratory of Computational Chemistry and Biochemistry	pascal.baillod at epfl.ch
> Room BCH 4121, Avenue Forel,	                        http://lcbcpc21.epfl.ch
> CH-1015 Lausanne	
> *******************************************************************************
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-- 
David.
________________________________________________________________________
David van der Spoel, PhD, Assoc. Prof., Molecular Biophysics group,
Dept. of Cell and Molecular Biology, Uppsala University.
Husargatan 3, Box 596,  	75124 Uppsala, Sweden
phone:	46 18 471 4205		fax: 46 18 511 755
spoel at xray.bmc.uu.se	spoel at gromacs.org   http://xray.bmc.uu.se/~spoel
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