[RNG-148] UnitSphereSampler does not check for infinite length dimension

• Type: Bug
• Status: Closed
• Priority: Trivial
• Resolution: Not A Problem
• Affects Version/s: 1.3
• Component/s: sampling
• Assignee: Unassigned
• Reporter: Alex Herbert
• Created: 30/Jun/21 08:26
• Updated: 13/Sep/21 10:41
• Resolved: 02/Aug/21 11:16

Description

The UnitSphereSampler does not check the vector to be normalised has infinite length.

A check is already made for zero length (see RNG-55) since the underlying Gaussian sampler can return zero values. A check should also be made for infinite length. The normalisation is only valid if the sum is a finite positive value.

The code can be fixed by changing:

if (sum == 0) {
    // Zero-norm vector is discarded.
    return sample();
}

to:

if (sum == 0 || sum == Double.POSITIVE_INFINITY) {
    // Invalid vector is discarded.
    return sample();
}

Issue Links

• is related to: RNG-55 UnitSphereSampler
• relates to: RNG-154 Avoid infinite samples in the normalised Gaussian samplers