13c refinement and minimization
Dr. John Badger
jb at MSI.COM
Wed Jan 7 15:12:08 EST 1998
The premature termination of the X-PLOR powell minimizer is
a problem of which we are aware. This behaviour seems to occur
most often when the energy term includes x-ray or NMR data.
A workaround is to create a loop that breaks the minimization
cycles into a series of small minimizations.
! Parameters for minimization
evaluate ($min_steps = 200 )
evaluate ($min_stage = 10 )
evaluate ($min_count = 0)
while ($min_stage > $min_count ) loop finalmin
evaluate ($min_count = $min_count + 1)
nstep = $min_steps
nprint = 25
end loop finalmin
would do 2000 steps of minimization as 10 x 200 steps
You could also use this strategy to put your own stopping
criteria into the loop if 2000 steps seems like overkill.
Product Development Manager, Macromolecular Crystallography
More information about the X-plor