Mailing-List: contact issues-help@commons.apache.org; run by ezmlm
Precedence: bulk
Reply-To: issues@commons.apache.org
Date: Wed, 14 Sep 2011 14:04:10 +0000 (UTC)
From: "Gilles (JIRA)" <jira@apache.org>
To: issues@commons.apache.org
Message-ID: 
 <1092259473.26688.1316009050178.JavaMail.tomcat@hel.zones.apache.org>
In-Reply-To: 
 <1529202690.9151.1314191969099.JavaMail.tomcat@hel.zones.apache.org>
Subject: [jira] [Commented] (MATH-650) FastMath has static code which slows
 the first access to FastMath
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit


    [ https://issues.apache.org/jira/browse/MATH-650?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13104507#comment-13104507 ] 

Gilles commented on MATH-650:
-----------------------------

Side note: The name {{USE_PRECOMPUTED_TABLES}} is misleading; it should be something like {{COMPUTE_TABLES}} in order to correspond to its usage.


> 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

--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira