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https://issues.apache.org/jira/browse/MATH-650?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13102262#comment-13102262
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Luc Maisonobe edited comment on MATH-650 at 9/11/11 11:14 AM:
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{quote}
We are not dealing with a "few seconds" of absolute running time: For each of
the 3 runs (single call, one hundred and one million calls), we gain no more
than about 45 milliseconds!
{quote}
On which type of computer do you get these figures ? The initial problem was
raised for low end devices. In fact, in the application we are speaking of, I
get a loading time that is very very long (tens of seconds, almost one minute,
not milliseconds). However, it is impossible for me to separate the time which
is due to FastMath from the time which is due to other initialization parts.
The initial benchmarks showed that FastMath was the major bottleneck.
was (Author: luc):
{quote}
We are not dealing with a "few seconds" of absolute running time: For each of
the 3 runs (single call, one hundred and one million calls), we gain no more
than about 45 milliseconds!
{quote}
On which type of computer do you get these figures ? The initial problem was
raised for low end devices. In fact, in the application we are speaking of, I
get a loading time that is very very long (tens of seconds, almost one minute,
not milliseconds). However, it is impossible for me to separate the time that
is due to FastMath from the time taht is due to other initialization parts. The
initial benchmarks showed that FastMath was the major bottleneck.
> 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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