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== Parameters ==<br />
<br />
; steps=''integer'': (default: 100)<br />
; level=''integer'': (default: 0)<br />
; flat=''integer'': (default: 100)<br />
; angdev=''real'': (default: 10.0)<br />
; vdwupdate=''integer'': (default: 100)<br />
<br />
== Description ==<br />
<br />
This command performs conjugate gradient minimization of the current<br />
structure with the following parameters:<br />
<br />
steps maximal number of minimization steps (target function<br />
evaluations)<br />
level maximal residue index difference for restraints<br />
that are included into the target function<br />
flat the minimization is stopped if the target function<br />
did not decrease by at least 1% in the given number<br />
of steps<br />
angdev maximal change of a dihedral angle (in degrees)<br />
between two updates of the van der Waals pair list<br />
vdwupdate maximal number of minimization steps between two<br />
updates of the van der Waals pair list<br />
<br />
If the information level is normal or higher, one line of information<br />
will be printed out as in the following example from the macro<br />
'''vtfmin''':<br />
<br />
Minimization (standard strategy):<br />
lev upper lower vdw angle target funct. |grad| #up #f stop<br />
# act # act # act # act begin end end<br />
0 115 13 0 0 313 26 84 9 282.65 0.13 1.8E-2 0 150 maxit<br />
1 271 47 0 0 925 73 84 5 163.09 3.79 0.16 34 150 maxit<br />
2 299 51 0 0 1067 81 84 5 24.71 3.79 0.11 18 150 maxit<br />
3 381 57 0 0 1240 92 84 8 694.27 4.22 0.27 20 116 flat<br />
4 431 74 0 0 1335 90 84 10 21.83 4.47 0.16 9 130 flat<br />
<br />
The first column gives the minimization level. Then, there are four<br />
times two columns giving the total number of restraints and the number<br />
of "active" restraints for the upper limit restraints, the lower<br />
limit restraints, the intrinsic van der Waals lower limit restraints,<br />
and the angle restraints, respectively. "Active" restraints are those<br />
that yield non-vanishing (but often small) contributions to the target<br />
function. The next columns give the value of the target function at<br />
the beginning and at the end of the minimization step, the norm of the<br />
gradient of the target function at the end of the minimization step,<br />
the number of updates of the van der Waals contact list, the number<br />
of target function evaluations, and a stop code.<br />
<br />
The following stop codes may occur:<br />
<br />
gradtl The squared norm of the gradient of the target<br />
function is smaller than the value of the parameter<br />
GSQTOL in the subroutine CGMIN.<br />
maxit The maximal number of target function evaluations,<br />
given by the parameter '''steps''', has been exceeded.<br />
linmin The maximal number of target function evaluations<br />
during the one-dimensional line minimization was<br />
exceeded without decreasing the target function.<br />
nostep The step size during line minimization became too small.<br />
uphill The direction of a conjugate gradient minimization<br />
step was uphill.<br />
const Several conjugate gradient steps did not succeed in<br />
decreasing the target function.<br />
flat The target function was minimized by less than 1%<br />
during the preceding ''flat'' minimization steps.<br />
stuck Several attempts to restart the conjugate minimizer<br />
after an update of the steric interaction pair list<br />
failed.<br />
<br />
Normal stop criteria are '''gradtl''', '''maxit''', and '''flat'''. Others should<br />
occur only rarely.<br />
<br />
== See also ==<br />
<br />
* [[vtfmin]]</div>Admin