# AMBER Archive (2009)Subject: Re: [AMBER] Ewald error estimated

From: Qinghua Liao (fantasticqhl_at_yahoo.com)
Date: Fri Sep 25 2009 - 02:48:14 CDT

Hi,

I think the "Ewald error estimate:  0.1017E-03" is normal, the error here means fluctuation, it is not an error. My understanding is that it is a standard to evaluate our systems. Your failure of heating from 100K to 150K maybe had nothing to do this, maybe it is some other problems!

Is that right? other  amber users?

Good luck!

Qinghua

________________________________
From: xuemeiwang1103 <xuemeiwang1103_at_163.com>
To: amber <amber_at_ambermd.org>
Sent: Friday, September 25, 2009 11:01:02 AM
Subject: [AMBER] Ewald error estimated

Dear Amber users:
I am prepare  to heat my protein system with PME method ,but there are problems puzzeld me .I want to konw the meaning of "Ewald error estimate:  0.1017E-03",is there something wrong with my initial structure ?when I run the heat.in ,I ignored the error ,but when I heat my system from 100K to 150k,it doesn't work. Althongh I have searched this error from mailintg list and got some information ,I still can't solve my problem ,Could someone give me one advice ?
Thank you !
My heat1.in
&cntrl
imin=0,irest=0,ntx=1,
nstlim=10000,dt=0.0002,
ntc=2,ntf=2,
ntt=0,
tempi=0.0,temp0=50.0,
ntb=1,cut=10,
ntr=0,
ntpr=1000,ntwx=500,ntwr=1000
/

the heat1.out

NSTEP =        0  TIME(PS) =      4.000  TEMP(K) =  218.43  PRESS =    0.0
Etot  =  -268864.0058  EKtot  =    36383.3139  EPtot      =  -305247.3197
BOND  =      420.3368  ANGLE  =      1694.9482  DIHED      =      4973.1812
1-4 NB =      1964.1169  1-4 EEL =    23707.1377  VDWAALS    =    50413.9674
EELEC  =  -388421..0080  EHBOND  =        0.0000  RESTRAINT  =        0.0000
Ewald error estimate:  0.1285E-03
------------------------------------------------------------------------------
........
R M S  F L U C T U A T I O N S

NSTEP =    10000  TIME(PS) =      2.000  TEMP(K) =    79.78  PRESS =    0.0
Etot  =    12949.1821  EKtot  =    13288.5211  EPtot      =      815.8535
BOND  =        8.3802  ANGLE  =        5.2773  DIHED      =        27.5222
1-4 NB =        23.9692  1-4 EEL =        32.0087  VDWAALS    =      2521.8048
EELEC  =      2862..4715  EHBOND  =        0.0000  RESTRAINT  =        0.0000
|E(PBS) =      375.2882
Ewald error estimate:  0.3655E-04

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