44 lines
1.6 KiB
Racket
44 lines
1.6 KiB
Racket
#lang typed/racket
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;;; dds/bn
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;;; This module provides some quick definitions for running Boolean
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;;; networks. A Boolean network is a set of Boolean variables which
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;;; are updated according to their corresponding update functions.
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;;; The variables to be updated at each step are given by the mode.
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(provide Variable State UpdateFunc Network
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update make-state make-bn)
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(define-type Variable Symbol)
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;;; A state of a Boolean network is a mapping from the variables of the
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;;; network to their Boolean values.
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(define-type State (HashTable Variable Boolean))
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;;; An update function is a Boolean function computing a Boolean value
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;;; from the given state.
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(define-type UpdateFunc (-> State Boolean))
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;;; A Boolean network is a mapping from its variables to its update
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;;; functions.
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(define-type Network (HashTable Variable UpdateFunc))
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;;; Given a state s updates all the variables from xs. This
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;;; corresponds to a parallel mode.
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(define (update [bn : Network] ; the Boolean network
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[s : State] ; the state to operate on
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[xs : (Listof Variable)]) ; the variables to update
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(let ([new-s : State (hash-copy s)])
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(for ([x xs])
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(let ([f (hash-ref bn x)])
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(hash-set! new-s x (f s))))
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new-s))
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;;; A version of make-hash restricted to creating Boolean states.
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(define (make-state [mappings : (Listof (Pairof Variable Boolean))])
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(make-hash mappings))
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;;; A version of make-hash restricted to creating Boolean networks.
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(define (make-bn [funcs : (Listof (Pairof Variable UpdateFunc))])
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(make-hash funcs))
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