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[MRG+1] MNT Use std math lib log1p instead of np.log1p in cython inner loops#11848

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qinhanmin2014 merged 1 commit intoscikit-learn:masterfrom
amueller:log1p
Aug 18, 2018
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[MRG+1] MNT Use std math lib log1p instead of np.log1p in cython inner loops#11848
qinhanmin2014 merged 1 commit intoscikit-learn:masterfrom
amueller:log1p

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@amueller amueller commented Aug 17, 2018

Reference Issues/PRs

Fixes performance regressions introduced in #11428 as discussed in #11476 (comment)

We should be using low level C functions in inner loops, not numpy functions.

@amueller amueller changed the title use std math lib log1p instead of numpy log1p in cython inner loops use std math lib log1p instead of np.log1p in cython inner loops Aug 17, 2018
@amueller amueller added this to the 0.20 milestone Aug 17, 2018
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amueller commented Aug 17, 2018 •
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FYI this if in the logistic function has pretty significant impact of the logistic regression runtime :-/ (or I'm hallucinating, not sure. scipy doesn't use the if right now it seems https://github.com/scipy/scipy/blob/master/scipy/special/_logit.c.src#L31 )

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LGTM, I can reproduce the regression. Sorry for the regression.

@qinhanmin2014 qinhanmin2014 changed the title use std math lib log1p instead of np.log1p in cython inner loops [MRG+1] MNT Use std math lib log1p instead of np.log1p in cython inner loops Aug 18, 2018
@qinhanmin2014 qinhanmin2014 merged commit 07e909a into scikit-learn:master Aug 18, 2018
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rth commented Aug 18, 2018

This failed in Appeveyor 32 bit on master, with,

ball_tree.obj : error LNK2019: unresolved external symbol _log1p referenced in function ___pyx_f_7sklearn_9neighbors_9ball_tree__log_kernel_norm
build\lib.win32-2.7\sklearn\neighbors\ball_tree.pyd : fatal error LNK1120: 1 unresolved externals

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qinhanmin2014 commented Aug 18, 2018 •
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This failed in Appeveyor 32 bit on master, with,

This is a rare accident. An error occurred in the PR (other jobs passed) so the failure is not detected. Possible solution might be simply revert the cython part of #11428

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qinhanmin2014 commented Aug 18, 2018

FYI I use log instead of log1p to pass the test on 32-bit Windows. See #11852

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