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https://issues.apache.org/jira/browse/MATH-725?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13199279#comment-13199279
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Gilles edited comment on MATH-725 at 2/2/12 10:22 PM:
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Those arrays cannot be "static" since their size depends on a parameter ("k")
passed to the constructor.
Please clarify what you proposed (or, better: provide a patch). Thanks.
was (Author: erans):
Those arrays cannot be "static" since their size depends on a parameter
("k") passed to the constructor.
> use initialized static final arrays, instead of initializing it in
> constructors
> -------------------------------------------------------------------------------
>
> Key: MATH-725
> URL: https://issues.apache.org/jira/browse/MATH-725
> Project: Commons Math
> Issue Type: Improvement
> Affects Versions: 2.2
> Reporter: Eldar Agalarov
> Priority: Minor
> Fix For: 3.0
>
> Original Estimate: 1h
> Remaining Estimate: 1h
>
> The Well PRNG's implementations have arrays iRm1, iRm2, iRm3, i1, i2, i3. All
> these arrays are unmodifiable, so we can replace this arrays initialization
> block
> final int w = 32;
> final int r = (k + w - 1) / w;
> this.v = new int[r];
> this.index = 0;
>
> // precompute indirection index tables. These tables are used for
> optimizing access
> // they allow saving computations like "(j + r - 2) % r" with costly
> modulo operations
> iRm1 = new int[r];
> iRm2 = new int[r];
> i1 = new int[r];
> i2 = new int[r];
> i3 = new int[r];
> for (int j = 0; j < r; ++j) {
> iRm1[j] = (j + r - 1) % r;
> iRm2[j] = (j + r - 2) % r;
> i1[j] = (j + m1) % r;
> i2[j] = (j + m2) % r;
> i3[j] = (j + m3) % r;
> }
> with inline initialized static final arrays.
> This is much better and faster implementation, freed from unnecessary costly
> calculations (such as %).
> Another solution: leave as is, but make all these arrays static.
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