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https://issues.apache.org/jira/browse/MATH-521?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12997696#comment-12997696
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Luc Maisonobe commented on MATH-521:
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Do you want to remove the guess method or to have default values just when the
guess fails ? We should add tests for such failures. I think one way to make it
fail would be for example to supply a constant sample with 0 values only for y,
or a set of points with only one value for x and random values for y.
I think for the frequency part, 0 is probably not a good choice and would lead
to numerical problems. Perhaps a value like 2PI/l where l is the range in X
would be better, it would start considering the sample covers exactly one
period.
The javadoc is for sure not perfect but is readable in a browser, which is the
main intend. The output is here:
[http://commons.apache.org/math/api-2.1/org/apache/commons/math/optimization/fitting/HarmonicCoefficientsGuesser.html].
Putting this in the user guide would be a nice addition.
> Changes in "HarmonicCoefficientsGuesser"
> ----------------------------------------
>
> Key: MATH-521
> URL: https://issues.apache.org/jira/browse/MATH-521
> Project: Commons Math
> Issue Type: Improvement
> Reporter: Gilles
> Assignee: Gilles
> Priority: Minor
> Labels: api-change, documentation
> Fix For: 3.0
>
>
> (1) The "guess" method throws "OptimizationException" when the algorithm
> fails to determine valid values for amplitude and angular frequency.
> There are no test showing how such a situation can occur.
> Moreover, since this procedure is used to provide an initial guess to an
> optimizer, it is better to pick any values for those parameters (e.g. zero)
> and let the optimizer proceed from that initial point.
> (2) The class javadoc seems very thorough in explaining the algorithm, but is
> quite unreadable in the source code, making it fairly useless for checking
> how the code complies with the comments. I think that this explanation should
> go in the user guide (and leave a mostly "plain text" outline of the
> algorithm, referring to the guide for details). [Does the format of the user
> guide allow such tricky (ASCII "art") constructs?]
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