Leabra Implementation Reference - Computational Explorations in Cognitive Neuroscience - page 453

C.6 Process-Level Variables

In addition to having parameters in the specification objects listed above, which are associated with state variable
objects in the network, the process objects contain some important variables, as described here.

EpochProcess epoch process-level specifications:

Variable Description
order Order to present events within the epoch in: SEQUENTIAL, PERMUTED (de-
fault), and RANDOM.
wt update Determines weight update mode. Leabra always uses either ON LINE (default)
for learning, or TEST for just presenting events but not learning.

LeabraTrialProcess trial process-level specifications:

Variable Description
phase order Number and order of phases to present.
phase no Current phase number.
phase Type of phase, minus or plus.
trial init How to initialize network state at start of trial. INIT STATE (default) initializes
activation state, but you must use DECAY STATE to retain context information
across trials for networks with context layers.
no plus stats Don't do stats or logging in the plus phase — true by default.
no plus test Don't run the plus phase when testing — true by default.

LeabraSettleProcess settle process-level specifications:

Variable Default Description

min cycles 60

Minimum number of cycles to settle for — this may need to be set larger for larger
networks that take longer to settle. Also, settling is typically cut off sooner by the
LeabraMaxDa statistic described below.

LeabraMaxDa Maximum delta-activation statistic, used to cut off settling after network has reached a stable state:

Variable Default Description

Type of activation change measure to use: can either use da (DA ONLY) or
I Net (INET ONLY) or both (INET DA — the default), where I Net is used
while there is no activity in the layer, and after that point da is used.

da type

1 How to scale the inet measure to be like da.

inet scale

lay avg thr .01

For INET DA, threshold for layer average activation to switch to da from Inet.

The absolute value of activation change (either da or Inet) — use this to set a
stopping criterion.

da