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https://issues.apache.org/jira/browse/MATH-650?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13100617#comment-13100617
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Luc Maisonobe commented on MATH-650:
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It's not that unlikely. At least it is a problem for me in several applications
and in this application too (disclaimer: Alexis works on this Android
application for me). The overhead is so large it really is becomes prohibitive
for me.
Concerning light-weight applications, I think the last changes Sebb introduced
are quite efficient. As far as I understand, only the tables that are used are
loaded. So if an application uses only the trigonometric functions, and not the
logarithm for example, it will load only these ones did I understood correctly ?
bq. I don't like having tables that huge in the source code just for the sake
of saving a few seconds.
Well, on my side, I don't like losing a few seconds just for the sake of
reducing source code size ;-) As usual our mileage does vary.
> 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
>
> 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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