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https://issues.apache.org/jira/browse/MATH-650?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13102339#comment-13102339
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Alexis Robert commented on MATH-650:
------------------------------------
If you want some stats on Android :
commons-math svn r1153648 : FastMath.<clinit> -- 9213.562ms
commons-math-3.0-20110907.123252-61.jar : FastMath.<clinit> -- 3.937ms
commons-math-3.0-20110907.222813-62.jar : FastMath.<clinit> -- 0.214ms
These times are given by traceview, a profiling tool used on Android. I used a
Google Nexus One (1GHz ARMv7 cpu), running Android 2.3.4, with the tracebased
JIT enabled.
(by the way, you must also take the profiling tool overhead into account. When
it tells 9s, it's more like ~4-5s without the profiling tool enabled.)
> FastMath has static code which slows the first access to FastMath
> -----------------------------------------------------------------
>
> Key: MATH-650
> URL: https://issues.apache.org/jira/browse/MATH-650
> Project: Commons Math
> Issue Type: Improvement
> Affects Versions: Nightly Builds
> Environment: Android 2.3 (Dalvik VM with JIT)
> Reporter: Alexis Robert
> Priority: Minor
> Attachments: FastMathLoadCheck.java
>
>
> Working on an Android application using Orekit, I've discovered that a simple
> FastMath.floor() takes about 4 to 5 secs on a 1GHz Nexus One phone (only the
> first time it's called). I've launched the Android profiling tool (traceview)
> and the problem seems to be linked with the static portion of FastMath code
> named "// Initialize tables"
> The timing resulted in :
> - FastMath.slowexp (40.8%)
> - FastMath.expint (39.2%)
> \- FastMath.quadmult() (95.6% of expint)
> - FastMath.slowlog (18.2%)
> Hoping that would help
> Thanks!
> Alexis Robert
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