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https://issues.apache.org/jira/browse/MATH-215?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Bernhard Grünewaldt updated MATH-215:
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Attachment: FastHadamardTransformerTest.java.diff
Implements suggestions of Luc Maisonobe - 27/Dec/08 08:51 AM
{quote}
The transform only uses two columns at a time from the matrix, wouldn't it be
possible to simply use two single dimension arrays only ?
I also think the check for n being a power of two can be done without the pow
and log functions by comparing n and Integer.highestOneBit.
{quote}
https://issues.apache.org/jira/browse/MATH-215?focusedCommentId=12659353#action_12659353
> Fast Hadamard Transform
> -----------------------
>
> Key: MATH-215
> URL: https://issues.apache.org/jira/browse/MATH-215
> Project: Commons Math
> Issue Type: New Feature
> Affects Versions: 1.0, 1.1, 1.2
> Reporter: Daniel Kuan
> Fix For: 2.1
>
> Attachments: FastHadamardTransformer.java.diff,
> FastHadamardTransformerTest.java.diff
>
>
> To date, the mathematical transforms package of Commons Maths,
> org.apache.commons.math.transform, only contains implementations for the
> Fourier, Sine, and Cosine transforms.
> This issue serves to propose and track the creation of an implementation for
> the Hadamard transform.
> Definition of the hadamard transform:
> http://en.wikipedia.org/wiki/Hadamard_transform#Definition
> Unfortunately, Mathworld does not provide a very detailed definition.
> http://mathworld.wolfram.com/HadamardTransform.html
> An elegant algorithm for the fast hadamard transform can be found here:
> http://www.archive.chipcenter.com/dsp/DSP000517F1.html
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