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https://issues.apache.org/jira/browse/MATH-621?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13099276#comment-13099276
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Dr. Dietmar Wolz commented on MATH-621:
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{quote}
I have written a lot of symmetric matrix code, and it ALWAYS outperforms any
Java library I can find, simply because I use the proper 1D array form of
storage.
{quote}
A previous version of the code (attached as version 0.4) directly uses 1D
arrays instead of Matrices and is definitely faster. But here in CM the focus
is to produce
code which is easily understandable. This way we have a chance to understand
and improve the algorithm itself. If performance of the optimization algo is
important
(which in many applications is not the case because "interesting" cost
functions are normally expensive to evaluate) then you could call the C-version
of
BOBYQA via JNI which gives you a performance boost of factor 6-10. This is
possible still using the CM interfaces and when the cost function
is implemented in Java.
> BOBYQA is missing in optimization
> ---------------------------------
>
> Key: MATH-621
> URL: https://issues.apache.org/jira/browse/MATH-621
> Project: Commons Math
> Issue Type: New Feature
> Affects Versions: 3.0
> Reporter: Dr. Dietmar Wolz
> Fix For: 3.0
>
> Attachments: BOBYQA.math.patch, BOBYQA.v02.math.patch,
> BOBYQAOptimizer.java.patch, BOBYQAOptimizer0.4.zip, bobyqa.zip,
> bobyqa_convert.pl, bobyqaoptimizer0.4.zip, bobyqav0.3.zip
>
> Original Estimate: 8h
> Remaining Estimate: 8h
>
> During experiments with space flight trajectory optimizations I recently
> observed, that the direct optimization algorithm BOBYQA
> http://plato.asu.edu/ftp/other_software/bobyqa.zip
> from Mike Powell is significantly better than the simple Powell algorithm
> already in commons.math. It uses significantly lower function calls and is
> more reliable for high dimensional problems. You can replace CMA-ES in many
> more application cases by BOBYQA than by the simple Powell optimizer.
> I would like to contribute a Java port of the algorithm.
> I maintained the structure of the original FORTRAN code, so the
> code is fast but not very nice.
> License status: Michael Powell has sent the agreement via snail mail
> - it hasn't arrived yet.
> Progress: The attached patch relative to the trunk contains both the
> optimizer and the related unit tests - which are all green now.
> Performance:
> Performance difference (number of function evaluations)
> PowellOptimizer / BOBYQA for different test functions (taken from
> the unit test of BOBYQA, dimension=13 for most of the
> tests.
> Rosen = 9350 / 1283
> MinusElli = 118 / 59
> Elli = 223 / 58
> ElliRotated = 8626 / 1379
> Cigar = 353 / 60
> TwoAxes = 223 / 66
> CigTab = 362 / 60
> Sphere = 223 / 58
> Tablet = 223 / 58
> DiffPow = 421 / 928
> SsDiffPow = 614 / 219
> Ackley = 757 / 97
> Rastrigin = 340 / 64
> The number for DiffPow should be dicussed with Michael Powell,
> I will send him the details.
> Open Problems:
> Some checkstyle violations because of the original Fortran source:
> - Original method comments were copied - doesn't follow javadoc standard
> - Multiple variable declarations in one line as in the original source
> - Problems related to "goto" conversions:
> "gotos" not convertible in loops were transated into a finite automata
> (switch statement)
> "no default in switch"
> "fall through from previos case in switch"
> which usually are bad style make no sense here.
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