[jira] Issue Comment Edited: (MATH-376) One-time initialization in "DirectSearchOptimizer"

["Gilles (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/MATH-376?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12879287#action_12879287 ] 

Gilles edited comment on MATH-376 at 6/16/10 8:36 AM:
------------------------------------------------------

Sorry, I should have read the documentation :-}. It would have me rephrased this issue as follows.
Considering the algorithm operation, is it a serious problem that the automatic default is used as initial simplex?
In the affirmative, instead of providing a default (as in the above excerpt) the code should throw an "IllegalStateException", signaling that "setStartConfiguration" must be called.
The alternative would be to extend the check:
{code}
if (startConfiguration == null
    ||  startConfiguration.length != startPoint.length) {
    // Re-initialize the default simplex with the appropriate number of vertices.
    // ...
}
{code}
Because it is confusing (and IMO doesn't make much sense) to allow one default run but not more.


      was (Author: erans):
    Sorry, I should have read the documentation :-}. It would have me rephrased this issue as follows.
Considering the algorithm operation, is it a serious problem that the automatic default is used as initial simplex?
In the affirmative, instead of providing a default (as in the above excerpt) the code should throw an "IllegalStateException", signaling that "setStartConfiguration" must be called.
The alternative would be to extend the check:
{code}
if (startConfiguration == null
    ||  (startConfiguration.length != startPoint.length) {
    // Re-initialize the default simplex with the appropriate number of vertices.
    // ...
}
{code}
Because it is confusing (and IMO doesn't make much sense) to allow one default run but not more.

  
> One-time initialization in "DirectSearchOptimizer"
> --------------------------------------------------
>
>                 Key: MATH-376
>                 URL: https://issues.apache.org/jira/browse/MATH-376
>             Project: Commons Math
>          Issue Type: Bug
>            Reporter: Gilles
>            Priority: Minor
>
> In class  "DirectSearchOptimizer" (in package "optimization.direct"), the "optimize" method contains this code (at line 270):
> {code}
> if (startConfiguration == null) {
>     // no initial configuration has been set up for simplex
>     // build a default one from a unit hypercube
>     final double[] unit = new double[startPoint.length];
>     Arrays.fill(unit, 1.0);
>     setStartConfiguration(unit);
> }
> {code}
> I think that this has the consequence that it is impossible to call "optimize" a second time, where one would like to solve a problem with a different dimension.

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.