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https://issues.apache.org/jira/browse/MATH-650?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13206195#comment-13206195
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Sebb commented on MATH-650:
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bq. I would lean on the binary side, for "safety" reasons: unwanted
modifications are less likely to occur.
Now that the arrays are cloned, I don't see how modifications can occur at run
time.
Source modifications are of course easier. But if that's a concern, let's store
all the code as resources!
bq. reading a presumably longer table, and parsing a presumably larger number
of octets for each double would result in a longer loading time
Why should the literal case need parsing? The compiler already parsed the
source when the class was compiled.
I don't see why the literal case should use more octets either.
I agree it would be nice to know the source of the "conventional wisdom" -
maybe the assumptions it was based on no longer hold.
> 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
> Fix For: 3.0
>
> Attachments: FastMathLoadCheck.java, LucTestPerformance.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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