[gmx-users] parallel question!!!

[PeiQuan Chen]

Dear gmx-users：

>Hm... you are getting a LAM error message, but you said you compiled  
>with mpich?

>"LAM" is never mentioned in Gromacs, so somewhere you must have  
>compiled something with LAM or used a lam command - perhaps FFTW?

>Cheers,

>Erik
Thank you for your help!Erik!
Yes I have compiled somthing with LAM or used a lam command of FFTW!
I have solved the problem after I have recompiled the FFTW!
But another problem accur:

I want to test the mdrun(with mpich-iccr),but I find a strange phenomenon:
I use the two -np nodes to test how fast the parallel caculation.so I use the tutor/water to test:

Method 1:
grompp -np 1 -f water.mdp -p water.top -c spc216.gro -o water.tpr
mpirun -echo -np 1 /home/pqchen/gromacs/i686-pc-linux-gnu/bin/mdrun -s water.tpr -o water.trr -c water_out.gro -v -g water.log  

Method 2
grompp -np 8 -f water.mdp -p water.top -c spc216.gro -o water.tpr
mpirun -echo -np 8 /home/pqchen/gromacs/i686-pc-linux-gnu/bin/mdrun -s water.tpr -o water.trr -c water_out.gro -v -g water.log

But the Method 2 consumes more time to caculate.Can anybody tell me why??Can anybody help me??

Thank you in advance!

Sincerely yours
---- 
PeiQuan Chen
________________________________________________________________________
PeiQuan Chen 	Department of Chemistry, Nankai University
WeiJin Road 94, TianJin, 300071, P.R.China
phone:	(86)2223506728		Mobile Phone: (+86)13920675030
gromacs at 163.com	
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