Commit 80d78438 authored Apr 08, 2019 by Hans-Peter Deifel

wta: Guard against too many transitions

When the user requests more transitions than the maximal number for the given
automaton, the current generator runs into an endless loop trying to find new
unused transitions. We now detect this case early and throw an error.

parent dbd78cf8

src/random-wta/Generator.hs

+5 −0

Original line number	Diff line number	Diff line
		@@ -112,6 +112,11 @@ genTransitions' numTransitions = do
		let n = numStates wtaSpec
		m = IndexedTransition.maxIndex wtaSpec

		-- FIXME Handle this case better. A nicer error output or something along this
		-- line.
		when (fromIntegral numTransitions >= m) $ do
		error $ "genTransitions: More transitions than possible requested"

		transitions <- lift $ map (IndexedTransition.fromIndex wtaSpec) <$> uniqueTransitions numTransitions m
		weightedTransitions <- (traverse.traverse.traverse) (const genMonoidValue) transitions

src/random-wta/IndexedTransition.hs

+3 −0

Original line number	Diff line number	Diff line
		{-# LANGUAGE ScopedTypeVariables #-}
		{-# LANGUAGE DerivingStrategies #-}
		{-# LANGUAGE GeneralizedNewtypeDeriving #-}

		module IndexedTransition (IndexedTransition(..), maxIndex, fromIndex) where

		@@ -10,6 +12,7 @@ import Data.Tuple
		import Types

		newtype IndexedTransition = Index Integer
		deriving newtype (Num, Eq, Ord)
		deriving (Show)

		maxIndex :: WTASpec m -> IndexedTransition