apache/mahout — pull request #6 by dlyubimov (2014-05-31 00:49:13+00:00)
Title: Mahout 1566 Regular ALS factorizer with convergence test

Few things happened here :

(1) default CacheHint for implicit optimizer checkpoint is changed to NONE (used to be: MEMORY-ONLY).
(2) bug fixes in the AB' physical operator found.
(3) added implicit drm -> inCore conversion which allows ALS iteration in its simplest form to look simply like

while (!stop && i < maxIterations) {

drmV = drmAt %*% drmU %*% solve(drmU.t %*% drmU)
drmU = drmA %*% drmV %*% solve(drmV.t %*% drmV)

...
i += 1
...
}