Replaced the multiplcation with the disp structure, to a replacement with a mask.
My timings are varying at my computer, so results are within the very same timing.
But for reading the code, having two masks, is essential better.
Task #7807 (https://gna.org/task/index.php?7807): Speed-up of dispersion models for Clustered analysis.
Authored by: tlinnet 2014-06-11
Parent: [r23843]
Child: [r23845]
