Information Technology Reference
In-Depth Information
C.2
Pseudocode
Outer loop: Iterate over events (trials) within an epoch. For each event:
1. Iterate over minus and plus phases of settling for each event.
(a) At start of settling, for all units:
i. Initialize all state variables (activation,
v_m
,etc).
ii. Apply external patterns (clamp input in minus, input & output in plus).
iii. Compute net input scaling terms (constants, computed here so network can be dynamically altered).
iv. Optimization: compute net input once from all static activations (e.g., hard-clamped external inputs).
(b) During each cycle of settling, for all non-clamped units:
i. Compute net input (
net
or
j
,and
g
i
if unit-based inhib) - sender-based optimization by ignoring inactives.
ii. Unless doing unit-based inhibition, compute kWTA inhibition, based on
g
i
(equation 3.2):
A. Sort units into two groups based on
gi
:top
k
and remaining
k +1
to
n
.
B. If basic kWTA, find
k
and
k +1th
highest, if average-based, compute average of
1
to
k
and
k +1
to
n
.
C. Set inhib conductance
g
i
between
k
and
k+1
for basic kWTA, or between averages for average-based.
iii. Compute point-neuron activation (incorporating netinput and inhibition).
(c) After settling, for all units:
i. Record final settling activations as either minus or plus phase (
act m
or
act p
).
2. After both phases, for all units & connections:
(a) Compute weight changes from plus-minus activations (error-driven) and plus-phase activations (Hebbian).
(b) Increment the weights according to computed changes.
C.3
Connection-Level Variables
We first describe the connection object, and then the specifications that control that object. Most object variables are
computed by the software, and should not be changed manually (they will just get overwritten) — only the specifica-
tions should be changed.
LeabraCon
connection object:
Variable
Description
The weight value (shows up in NetView as r.wt for receiving, s.wt for sending
wt
Accumulated change in weight value computed for current trial: this is usually
zero by the time NetView is updated
dwt
pdw
Previous dwt weight change value: this is what is visible in NetView.
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