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Gilles commented on MATH-650: ----------------------------- {{FastMathLoadCheck}} (revision 1180294): {noformat} Using exp(100); how=compute times result 42677576 2.688117e+43 5338 2.688117e+43 1831 2.688117e+43 1759 2.688117e+43 Using exp(100); how=resources times result 12930977 2.688117e+43 4650 2.688117e+43 2322 2.688117e+43 2496 2.688117e+43 Using exp(100); how=array times result 12281292 2.688117e+43 4824 2.688117e+43 1807 2.688117e+43 1877 2.688117e+43 Using max(0,0); how=compute times result 3293 0.000000e+00 1110 0.000000e+00 375 0.000000e+00 376 0.000000e+00 Using max(0,0); how=resources times result 2680 0.000000e+00 713 0.000000e+00 382 0.000000e+00 367 0.000000e+00 Using max(0,0); how=array times result 3065 0.000000e+00 520 0.000000e+00 370 0.000000e+00 376 0.000000e+00 {noformat} > 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, 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 -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira