View source for Minimizing a structure using OPTIM and CHARMM

To optimize a geometry you need an input.crd file, as well as odata:

1. ''input.crd'' -- file with coordinates in CHARMM'S CARD format

2. ''odata'' -- file with OPTIM keywords specifying method of minimization, convergence criterion, etc. e.g.:
  
   BFGSMIN 1.0D-6
   BFGSSTEPS 10000
   UPDATES 1000
   MAXERISE 1.0D-4
   ENDHESS (optional, if you want to know the log product of positive Hessian eigenvalues)
   CHARMMTYPE toph19_eef1_perm.inp param19_eef1_perm.inp
   CHARMM
   ... the usual charmm stuff, but making sure that input.crd is the file from which the coordinates are read in, for example:
   OPEN UNIT 20 NAME input.crd READ CARD
   ...