Hi all,

The new addUnknownAtoms function is very timely as it's exactly what I
need.  I did notice a problem with it, however.  In the middle of the
calculation, the program stop, claiming that it was missing an atom.  I
found that by decreasing the timestep, and increasing the number of steps,
I could work around this problem.

I also copied some code from tutorial/tidbits/sidechainbuild.inp that
should take care of the changing mass problem in addUnknownAtoms, though
I haven't tested it yet.  Patch including both changes is attached.

One question - I think it would be useful to see the output of the
minimization in addUnknownAtoms, but when I turn on the normal output, I
get a huge number of %atom warnings about atoms being too close together.
Is there a way to shut the %atom warnings off, but preserve the rest of
the minimization output?

-Greg Zornetzer
[email protected]
-------------- next part --------------
--- python/protocol.py.orig     2005-12-14 14:13:52.000000000 -0600
+++ python/protocol.py  2005-12-14 14:22:41.000000000 -0600
@@ -686,6 +686,7 @@
     xplor.command(r"""

 vector do (fbeta=10) (not known)    {*Friction coefficient for MD heatbath.*}
+vector do (q=mass)   (all)      {* Save the real masses for later *}
 vector do (mass=100) (not known)            {*Uniform heavy masses to speed*}
 vector do (fbeta=0) (known)    {*Friction coefficient for MD heatbath.*}
 vector do (mass=0)  (known)              {*Uniform heavy masses to speed*}
@@ -732,8 +733,8 @@

     evaluate ($kbon = 0.00005  )                 {* Bonds.                 *}
     evaluate ($kang = 0.00005  )                 {* Angles.                *}
-    evaluate ($timestep = 0.04)
-    evaluate ($nstep = 100)
+    evaluate ($timestep = 0.004)
+    evaluate ($nstep = 1000)

     !constraints 
     !   interaction (all) (all) 
@@ -789,7 +790,7 @@
         weights bond $kbon angl $kang impr $kimp vdw 0.002 elec 0 end 
     end
     dynamics  verlet
-          nstep=500   timestep=$timestep   iasvel=current   
+          nstep=5000   timestep=$timestep   iasvel=current   
           tcoupling=true tbath=$init_t  nprint=50  iprfrq=0 
     end            
     constraints 
@@ -799,7 +800,7 @@
         weights bond $kbon angl $kang impr $kimp vdw 0.005 elec 0 end 
     end
     dynamics  verlet
-          nstep=500   timestep=$timestep   iasvel=current   
+          nstep=5000   timestep=$timestep   iasvel=current   
           tcoupling=true tbath=$init_t  nprint=50  iprfrq=0 
     end            
     constraints 
@@ -809,7 +810,7 @@
         weights bond $kbon angl $kang impr $kimp vdw 0.01 elec 0 end 
     end
     dynamics  verlet
-          nstep=500   timestep=$timestep   iasvel=current   
+          nstep=5000   timestep=$timestep   iasvel=current   
           tcoupling=true tbath=$init_t  nprint=50  iprfrq=0 
     end            
     constraints 
@@ -819,7 +820,7 @@
         weights bond $kbon angl $kang impr $kimp vdw 0.5 elec 0 end 
     end
     dynamics  verlet
-          nstep=500   timestep=$timestep   iasvel=current   
+          nstep=5000   timestep=$timestep   iasvel=current   
           tcoupling=true tbath=$init_t  nprint=50  iprfrq=0 
     end            

@@ -844,8 +845,12 @@
   drop=100
   nprint=1
   tolg=1e-5
-  nstep=10000
-end""")
+  nstep=10000  
+end
+
+vector do (mass=q) (all) {* Return the masses to sane values *}
+
+""")
     xplor.command("set mess=%s print=OUTPUT echo=%s end"%(old_mess,old_echo))
     return

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