+--------------------------------------------------------------------+
| |
| $ANNEAL |
| |
+--------------------------------------------------------------------+
MEANING: Sets starting diagonal Omega values to facilitate EM search |
methods
CONTEXT: NM-TRAN Control Record
USAGE:
$ANNEAL number-list1:value1 number-list2:value2 ...
SAMPLE:
$ANNEAL 1-3,5:0.3 6,7:1.0
DISCUSSION:
Sets starting diagonal Omega values for purposes of simulated anneal-
ing by NONMEM subroutine CONSTRAINT.
In the above example, initial values of OMEGA(1,1), OMEGA(2,2),
OMEGA(3,3), and OMEGA(5,5) are set to 0.3, while initial OMEGA(6,6)
and OMEGA(7,7) are set to 1.0.
A number-list may contain a single integer, a range of integers (with
-), or a series of integers and ranges separated by comma. Required.
A value may be any numeric value. Optional; default is 0.
When $EST CONSTRAIN>=4, an algorithm in subroutine CONSTRAINT will
initially set the omegas to these values, and then shrink these OMEGA
values more and more with each iteration, and eventually shrinks the
OMEGA's to 0, the intended target value for that Omega. This is a
technique that may be used especially with SAEM, to provide an anneal-
ing method for moving thetas that have 0 omega values associated with
them. The default is the use of gradient methods, which are good for
problems starting near the solution, whereas the annealing method is
more suitable for problems starting far from the solution.
Subroutine CONSTRAINT obtains values entered via $ANNEAL record in the
array OMEGANNL. Any value that is set to 0 in $ANNEAL is given the
default value of .3.
This record is optional. If omitted, the starting values of Omega are
those specified in the $OMEGA record.
NONMEM's default CONSTRAINT.f90 is identical to Subroutine source/CON-
STRAINT.f90.
See INTRODUCTION TO NONMEM 7, $ANNEAL to facilitate EM search methods
REFERENCES: Guide Introduction_7
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