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			= minimize =

	== Parameters ==		== Parameters ==

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== Parameters ==

; steps=''integer'': (default: 100)
; level=''integer'': (default: 0)
; flat=''integer'': (default: 100)
; angdev=''real'': (default: 10.0)
; vdwupdate=''integer'': (default: 100)

== Description ==

This command performs conjugate gradient minimization of the current
structure with the following parameters:

steps maximal number of minimization steps (target function
evaluations)
level maximal residue index difference for restraints
that are included into the target function
flat the minimization is stopped if the target function
did not decrease by at least 1% in the given number
of steps
angdev maximal change of a dihedral angle (in degrees)
between two updates of the van der Waals pair list
vdwupdate maximal number of minimization steps between two
updates of the van der Waals pair list

If the information level is normal or higher, one line of information
will be printed out as in the following example from the macro
'''vtfmin''':

Minimization (standard strategy):
lev upper lower vdw angle target funct. |grad| #up #f stop
# act # act # act # act begin end end
0 115 13 0 0 313 26 84 9 282.65 0.13 1.8E-2 0 150 maxit
1 271 47 0 0 925 73 84 5 163.09 3.79 0.16 34 150 maxit
2 299 51 0 0 1067 81 84 5 24.71 3.79 0.11 18 150 maxit
3 381 57 0 0 1240 92 84 8 694.27 4.22 0.27 20 116 flat
4 431 74 0 0 1335 90 84 10 21.83 4.47 0.16 9 130 flat

The first column gives the minimization level. Then, there are four
times two columns giving the total number of restraints and the number
of "active" restraints for the upper limit restraints, the lower
limit restraints, the intrinsic van der Waals lower limit restraints,
and the angle restraints, respectively. "Active" restraints are those
that yield non-vanishing (but often small) contributions to the target
function. The next columns give the value of the target function at
the beginning and at the end of the minimization step, the norm of the
gradient of the target function at the end of the minimization step,
the number of updates of the van der Waals contact list, the number
of target function evaluations, and a stop code.

The following stop codes may occur:

gradtl The squared norm of the gradient of the target
function is smaller than the value of the parameter
GSQTOL in the subroutine CGMIN.
maxit The maximal number of target function evaluations,
given by the parameter '''steps''', has been exceeded.
linmin The maximal number of target function evaluations
during the one-dimensional line minimization was
exceeded without decreasing the target function.
nostep The step size during line minimization became too small.
uphill The direction of a conjugate gradient minimization
step was uphill.
const Several conjugate gradient steps did not succeed in
decreasing the target function.
flat The target function was minimized by less than 1%
during the preceding ''flat'' minimization steps.
stuck Several attempts to restart the conjugate minimizer
after an update of the steric interaction pair list
failed.

Normal stop criteria are '''gradtl''', '''maxit''', and '''flat'''. Others should
occur only rarely.

== See also ==

* [[vtfmin]]

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