AMBER Archive (2008)

Subject: AMBER: simulated annealing

From: Holly Freedman (freedman_at_phys.ualberta.ca)
Date: Thu Feb 21 2008 - 13:31:48 CST

Dear AMBER,
I am trying to do annealing after have heated my system to 700K. The input file I am using is pasted
below. My problem is that the system is cooling much faster than the input file seems to be asking it
to: After only 1400 steps the temperature is down to 325. I would very much appreciate it if
someone could explain to me why - do have a wrong parameter in the input file? Also is it
necessary for me to cool the system as slowly as I am trying to?
Thanks,
Holly

simulated annealing
 &cntrl
  imin = 0, irest = 1, ntx=5,
  ntc=2, ntf=2, ntr = 1,
  ntpr=20, ntwx=100,
  ntb = 0, cut = 50.0, rgbmax=50.0,
  igb = 1, saltcon=0.05,
  nstlim = 32000,
  dt = 0.001,
  ntt = 3, gamma_ln=5.0,
  nmropt=1, restraint_wt = 50,
  restraintmask=
  ':1-872_at_CA',
 /
 &wt type='TEMP0', istep1=0,istep2=2000,
   value1=700.0, value2=650.0
 /
 &wt type='TEMP0', istep1=2001,istep2=4000,
   value1=650.0, value2=650.0
 /
 &wt type='TEMP0', istep1=4001,istep2=6000,
   value1=650.0, value2=600.0
 /
 &wt type='TEMP0', istep1=6001,istep2=8000,
   value1=600.0, value2=600.0
 /
 &wt type='TEMP0', istep1=8001,istep2=10000,
   value1=600.0, value2=550.0
 /
 &wt type='TEMP0', istep1=10001,istep2=12000,
   value1=550.0, value2=550.0
 /
 &wt type='TEMP0', istep1=12001,istep2=14000,
   value1=550.0, value2=500.0
 /
 &wt type='TEMP0', istep1=14001,istep2=16000,
   value1=500.0, value2=500.0
 /
 &wt type='TEMP0', istep1=16001,istep2=18000,
   value1=500.0, value2=450.0
 /
 &wt type='TEMP0', istep1=18001,istep2=20000,
   value1=450.0, value2=450.0
 /
 &wt type='TEMP0', istep1=20001,istep2=22000,
   value1=450.0, value2=400.0
 /
 &wt type='TEMP0', istep1=22001,istep2=24000,
   value1=400.0, value2=400.0
 /
 &wt type='TEMP0', istep1=24001,istep2=26000,
   value1=400.0, value2=350.0
 /
 &wt type='TEMP0', istep1=26001,istep2=28000,
   value1=350.0, value2=350.0
 /
 &wt type='TEMP0', istep1=28001,istep2=30000,
   value1=350.0, value2=300.0
 /
 &wt type='TEMP0', istep1=30001,istep2=32000,
   value1=300.0, value2=300.0
 /
 &wt type='END'
 /
  

--
Department of Physics, University of Alberta
Edmonton CANADA

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