[MATH-725] use initialized static final arrays, instead of initializing it in constructors

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Incomplete
• Affects Version/s: 2.2
• Fix Version/s: 3.0
• Assignee: Unassigned
• Reporter: Eldar Agalarov
• Created: 13/Dec/11 23:46
• Updated: 24/Mar/12 16:23
• Resolved: 14/Feb/12 00:32

Description

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.