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https://issues.apache.org/jira/browse/MATH-1305?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Gilles resolved MATH-1305.
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Resolution: Fixed
> Improve performance of nextBytes() method of BitsStreamGenerator and
> AbstractRandomGenerator
> ---------------------------------------------------------------------------------------------
>
> Key: MATH-1305
> URL: https://issues.apache.org/jira/browse/MATH-1305
> Project: Commons Math
> Issue Type: Improvement
> Affects Versions: 4.0, 3.5, 3.6
> Reporter: Rostislav Krasny
>
> I propose to use this code in {{BitsStreamGenerator}}
> {code:java}
> @Override
> public void nextBytes(byte[] bytes) {
> int index = 0;
> // multiple 4 part of length, i.e. length with two least
> significant bits unset
> int max = bytes.length & 0x7ffffffc;
> // start filling the byte array with tetrads of bytes
> while (index < max) {
> int random = next(32);
> bytes[index++] = (byte) random;
> bytes[index++] = (byte) (random >>> 8);
> bytes[index++] = (byte) (random >>> 16);
> bytes[index++] = (byte) (random >>> 24);
> }
> // fill the remains bytes
> if (index < bytes.length) {
> int random = next(32);
> while (true) {
> bytes[index++] = (byte) random;
> if (index < bytes.length) {
> random >>>= 8;
> } else {
> break;
> }
> }
> }
> }
> {code}
> I also propose to use the same code but with {{nextInt()}} calls instead of
> {{next(32)}} in the {{AbstractRandomGenerator}}. This implementation improves
> performance and fixes inconsistency bugs in those two classes discussed in
> the MATH-1300. It is also quite simple and well commented.
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