[AMBER] Center of mass restraints work on pmemd.MPI, but not on the GPU

From: mmaestre <mmaestre.gate.sinica.edu.tw>
Date: Thu, 26 Feb 2015 12:19:51 +0800 (CST)

Dear Amber users/developers

A while ago I posted the message I am reproducing below. I haven't received any comments on my problem, and I still am not able to solve it by myself. I've noticed, though, that the message does not appear as a new thread, but as a reply to an unrelated thread. This is probably my fault, as I probably started it by replying to the unrelated thread and editing the message. Thus, I am hoping that that's the reason for the absence of replies, and that someone might give me a hand ;)
I am now re-posting the message, using a completely new thread.

Thanks a lot, and sorry if this was unnecessary, but I'd be really interested in getting this to run!

Manuel

Here is my original message:


Der Amber users,

I've been dealing lately with a protein-dna complex, in which I want to compare the dna behavior in the presence and absence of an experimentally determined (via FRET) distance restraint.
Since, since last month, COM restraints are available in pmemd.cuda, I decided to give them a try.
My results are not really encouraging...
When using the following control file:

&cntrl
 imin=0,irest=0,ntx=7,ioutfm=1,nmropt=1
 ntb=2,pres0=1.0,ntp=1,barostat=2
 taup=2.0,
 ntr=1,ntc=2,ntf=2,
 tempi=300.0,temp0=300.0,ntt=3,ig=-1,gamma_ln=5
 nstlim=1000000,dt=0.002,
 ntpr=10000,ntwx=10000,ntwr=100000
 cut=8
/
&wt type='DUMPFREQ', istep1=2 /
&wt type='REST', istep1=0,istep2=1000000,value1=0.1,
           value2=1, /
&wt type='END' /
DISANG=res.RST
DUMPAVE=bent_res_immo_min5.rst
LISTIN=POUT
LISTOUT=POUT
END

With the following restraint file:
&rst iat= -1,-1, r1= 49.8, r2= 50.8, r3=55.76, r4=56.76, rk2=1, rk3=0.1, ir6=1, ialtd=0, igr1=1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63, igr2=579,580,581,582,583,584,585,586,587,588,589,590,591,592,593,594,595,596,597,598,599,600,601,602,603,604,605,606,607,608,609,610,611,612,613,614,615,616,617,618,619,620,621,622,623,624,625,626,627,628,629,630,631,632,633,634,635,636,637 /

I consistently get ~20 setps, after which the following error appears:
Error: an illegal memory access was encountered launching kernel kClearForces
cudaFree GpuBuffer::Deallocate failed an illegal memory access was encountered

I've tried it on GTX780 and on K20 cards, with the same results.

If I run the same simulation on CPUs, or if I modify the restraint file to present an atom based restraint, instead of a center of mass based one (i.e. i delete igr1 and igr2, and substitute iat= -1,-1, for iat= 1,579) and run it on either of the GPUs, the simulation can be run successfully.

I am not sure if my input files are bad, or if there might be any bugs on the COM implementation, but just thought it might be useful to post it here, and get some comments.

Thank you very much,
Manuel

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Received on Wed Feb 25 2015 - 20:30:03 PST
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