What does DEFAULTS['kind']['iterations'] refer to in loom/loom/config.py?

[ajaysaini725]

It seems as if extra_passes in DEFAULTS refers to the number of Gibbs passes through the parameters. If this is the case, then what does the DEFAULTS['kind']['iterations'] parameter refer to?
Source: https://github.com/posterior/loom/blob/master/loom/config.py#L35

[fritzo]

Loom has three kernels:

• a "cat" kernel that reassigns objects via subsample-annealed Gibbs sampling,
• a "hyper" kernel that samples hyperparameters for features and the Pitman-Yor clustering prior, and
• a "kind" kernel that samples kind structure (aka view structure, aka partitioning of features).

The "cat" kernel is controlled by extra_passes, which determines the subsample annealing schedule. While loom is running subsample annealing, objects are added-to and removed-from the latent state. Whenever the set of assigned objects is completely "fresh", loom considers this to be a full minibatch and runs the "hyper" and "kind" kernels, and finally marks these objects as "dirty"; they must all be removed before the next minibatch.

Within each minibatch, the two kernels are controlled by DEFAULTS['kernels']['hyper'] and DEFAULTS['kernels']['kind']. So for example the "kind" kernel is run for DEFAULTS['kernels']['kind']['iters'] during each minibatch. (The kind kernel is a very cheap single-threaded kernel).