start_w

Note: Only applicable in the A-learning and the Actor-Critic mechanisms.

Specifies the initial value for w-values (conditioned reinforcement for a stimulus element).

The parameter start_w can be set to certain values for certain particular stimulus elements. It can also be specified as a single value, in which case the same initial value is used for all stimulus elements.

Syntax

start_w = e1: v1, e2: v2, ..., en: vn, default: d
start_w = v1

where v1,v2,...,vn are scalar expressions.

Description

start_w = e1: v1, e2: v2, ..., en->bn: vn, default: d sets the initial value for

• w(e1) to v1,

• w(e2) to v2, …,

• w(en) to vn,

and the initial value for all other w-values to d.

• The specification is independent of the list order:

  start_w = e1:v1, e2:v2, default:d

  is the same as

  start_w = e2:v2, default:d, e1:v1.

• default need not be specified if all stimulus elements are present in the list. For example,

  stimulus_elements = e1, e2
  start_w = e1:v1, e2:v2
  

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start_w = v1 sets the initial value for all w-values to v1.

• start_w = v1 is the same as start_w = default: v1.

Dependencies

• The property stimulus_elements must be specified before start_w.

• Each stimulus element used in the specification of start_w must be present in the parameter stimulus_elements.

• Applicable only in the A-learning and Actor-Critic mechanisms.

Examples

@variables x = 1
start_w = element1: x, element2: x+1, default:x+2

sets the initial value for w(element1) to 1 and for w(element2) to 2, and for the remaining stimulus elements to 3.

start_w = element1: 0.5, default:0

sets the initial value for w(element1) to 0.5, and for the remaining stimulus elements to 3.

start_w = 0.1

sets the initial value for all w-values to 0.1.