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https://issues.apache.org/jira/browse/MATH-621?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13087408#comment-13087408
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Gilles commented on MATH-621:
-----------------------------
I tried to replace a loop with a matrix operation: The computation of the first
"sum" in "case 90" (line 564). Although the new and old computations differ by
less than 1e-15, they induce failures:
{noformat}
Failed tests:
testAckley(org.apache.commons.math.optimization.direct.BOBYQAOptimizerTest):
expected:<0.0> but was:<1.0731970423449866E-8>
Tests in error:
testDiffPow(org.apache.commons.math.optimization.direct.BOBYQAOptimizerTest):
illegal state: maximal count (12,000) exceeded: evaluations
{noformat}
The first is possibly (?) acceptable due to numerical errors but the second
seems more problematic.
Anyways, it looks like these kinds of code transformation should not be
attempted at this point.
> 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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