[scikit-learn] Fwd: inconsistency between libsvm and scikit-learn.svc results

[elgesto at gmail.com]

Can I update the libsvm version by myself?

2016-08-27 12:49 GMT+03:00 olologin <olologin at gmail.com>:

> On 08/27/2016 12:33 PM, elgesto at gmail.com wrote:
>
> I have a project that is based on SVM algorithm implemented by libsvm
> <https://www.csie.ntu.edu.tw/%7Ecjlin/libsvm/>. Recently I decided to try
> several other classification algorithm, this is where scikit-learn
> <http://scikit-learn.org/> comes to the picture.
>
> The connection to the scikit was pretty straightforward, it supports
> libsvm format by load_svmlight_file routine. Ans it's svm implementation
> is based on the same libsvm.
>
> When everything was done, I decided to the check the consistence of the
> results by directly running libsvm and via scikit-learn, and the results
> were different. Among 18 measures in learning curves, 7 were different, and
> the difference is located at the small steps of the learning curve. The
> libsvm results seems much more stable, but scikit-learn results have some
> drastic fluctuation.
>
> The classifiers have exactly the same parameters of course. I tried to
> check the version of libsvm in scikit-learn implementation, but I din't
> find it, the only thing I found was libsvm.so file.
>
> Currently I am using libsvm 3.21 version, and scikit-learn 0.17.1 version.
>
> I wound appreciate any help in addressing this issue.
>
>
> size    libsvm                  scikit-learn
> 1       0.1336239435355727      0.1336239435355727
> 2       0.08699516468193455     0.08699516468193455
> 3       0.32928301642777424     0.2117238289550198      #different
> 4       0.2835688734876902      0.2835688734876902
> 5       0.27846766962743097     0.26651875338163966     #different
> 6       0.2853854654662907      0.18898048915599963     #different
> 7       0.28196058132165136     0.28196058132165136
> 8       0.31473956032575623     0.1958710201604552      #different
> 9       0.33588303670653136     0.2101641630182972      #different
> 10      0.4075242509025311      0.2997807499800962      #different
> 15      0.4391771087975972      0.4391771087975972
> 20      0.3837789445609818      0.2713167833345173      #different
> 25      0.4252154334940311      0.4252154334940311
> 30      0.4256407777477492      0.4256407777477492
> 35      0.45314944605858387     0.45314944605858387
> 40      0.4278633233755064      0.4278633233755064
> 45      0.46174762022239796     0.46174762022239796
> 50      0.45370452524846866     0.45370452524846866
>
>
>
>
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>
> This might be because current version of libsvm used in scikit is 3.10
> from 2011. With some patch imported from upstream.
>
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