Friendly reminder, because I think it has fallen off the TODO-list. The new atomese formula support is likely to be a lot faster than using (GroundedPredicateNode "scm:foo-formula") See https://github.com/opencog/atomspace/blob/master/examples/atomspace/formulas.scm for a working example; I copy part of it below to give a flavor of it:
; Create a SimpleTruthValue with a non-trivial formula:
; It will be the TV := (1-sA*sB, cA*cB) where sA and sB are strenghts
; and cA, cB are confidence values. The PredicateFormulaLink assembles
; two floating-point values, and create a SimpleTruthValue out of them.
;
(cog-evaluate!
(PredicateFormula
(Minus
(Number 1)
(Times (StrengthOf (Concept "A")) (StrengthOf (Concept "B"))))
(Times (ConfidenceOf (Concept "A")) (ConfidenceOf (Concept "B")))))
; The values do not need to be formulas; they can be hard-coded numbers.
(cog-evaluate!
(PredicateFormula (Number 0.7) (Number 0.314)))
; The below computes a truth value, and attaches it to the
; EvaluationLink. Let's demo this in three parts: first define it,
; then evaluate it, then look at it.
;
(define my-ev-link
(Evaluation
(PredicateFormula (Number 0.7) (Number 0.314))
(List
(Concept "A")
(Concept "B"))))
; Evaluate ...
(cog-evaluate! my-ev-link)
; Print.
(display my-ev-link)
; More typically, one wishes to have a formula in the abstract,
; with variables in it, so that one can apply it in any one of
; a number of different situations. In the below, the variables
; are automatically reduced with the Atoms in the ListLink, and
; then the formula is evaluated to obtain a TruthValue.
(cog-evaluate!
(Evaluation
; Compute TV = (1-sA*sB, cA*cB)
(PredicateFormula
(Minus
(Number 1)
(Times
(StrengthOf (Variable "$X"))
(StrengthOf (Variable "$Y"))))
(Times
(ConfidenceOf (Variable "$X"))
(ConfidenceOf (Variable "$Y"))))
(List
(Concept "A")
(Concept "B"))))
and so on. The example gives even more details that make it even more PLN-useful.
Friendly reminder, because I think it has fallen off the TODO-list. The new atomese formula support is likely to be a lot faster than using
(GroundedPredicateNode "scm:foo-formula")See https://github.com/opencog/atomspace/blob/master/examples/atomspace/formulas.scm for a working example; I copy part of it below to give a flavor of it:and so on. The example gives even more details that make it even more PLN-useful.