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From "Sebb (JIRA)" <j...@apache.org>
Subject [jira] [Issue Comment Edited] (MATH-650) FastMath has static code which slows the first access to FastMath
Date Sun, 11 Sep 2011 16:50:08 GMT

    [ https://issues.apache.org/jira/browse/MATH-650?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13102300#comment-13102300
] 

Sebb edited comment on MATH-650 at 9/11/11 4:48 PM:
----------------------------------------------------

Very simple test to demonstrate effect of IOD and calculate.

Requires that FastMath.USE_PRECOMPUTED_TABLES be set to package-protected and non-final.
Should be set back to final before release.

      was (Author: sebb@apache.org):
    Very simple test to demonstrate effect of IOD and calculate.

Requires that FastMath.USE_PRECOMPUTED_TABLES be set to package-protected and non-final.

Should be set back to final before release.
  
> 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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