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From "Alexis Robert (JIRA)" <j...@apache.org>
Subject [jira] [Created] (MATH-650) FastMath has static code which slows the first access to FastMath
Date Wed, 24 Aug 2011 13:19:29 GMT
FastMath has static code which slows the first access to FastMath
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                 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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