[gmx-users] grompp error with new format of angletypes

[Justin A. Lemkul]

Hyunjin Kim wrote:
> Dear,
> 
> When I generated bond parameters as following and ran "grompp", then I had
> an error messages "No default Angle types"
> 
> 
> [ angletypes ]
> ; i     j       k       func    th0     cth     ub0     cub
> OST     CST     OST     5       180.0000        25104.0 0.0     0.0
> CS      SS      FE      5       100.6   418.4   0.0     0.0
> ..................
> 
> 
> When "func" number was chosen to "1" and removed "ub0" and "cub" terms,
> the error did not occurred. Does anyone know how to use the above angle
> types in the parameter file without any error, please let me know. I

The error comes from the fact that you're defining an angletype that does not 
exist.  You shouldn't be hacking ffbonded.itp to try to solve this problem, you 
should be making sure that your topology calls angletypes that are actually 
present in the force field.  If they're not, either define them manually or use 
a different force field that is suited to your application.  Hacking the 
ffbonded.itp file is a great way to invalidate a force field.

> appreciate that in advance. Can this problem be related to the version of
> gromacs? I am sure that gromacs I have here is 4.0. or higher, but it
> might not be 4.5. or higher.
> 

Based on the fact that this snippet appears to be from the CHARMM force field, 
you're probably using 4.5 or higher.  If you don't know, you can find out by 
issuing any command with the -h argument and reading the information printed, 
among which the "VERSION" string should be prominent.  After you know what 
you're using, refer to the appropriate manual and any information therein about 
how to properly use the force field you want.

-Justin

> Thanks.
> 
> Hyunjin.
> 
> 
> 

-- 
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Justin A. Lemkul
Ph.D. Candidate
ICTAS Doctoral Scholar
MILES-IGERT Trainee
Department of Biochemistry
Virginia Tech
Blacksburg, VA
jalemkul[at]vt.edu | (540) 231-9080
http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin

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