Linear.Simplex.Util

Helper functions for performing the two-phase simplex method.

Documentation

isMax :: ObjectiveFunction -> Bool

Is the given ObjectiveFunction to be Maximized?

simplifySystem :: [PolyConstraint] -> [PolyConstraint]

Simplifies a system of PolyConstraints by first calling simplifyPolyConstraint, then reducing LEQ and GEQ with same LHS and RHS (and other similar situations) into EQ, and finally removing duplicate elements using nub.

dictionaryFormToTableau :: Dict -> Tableau

Converts a Dict to a Tableau using dictEntryToTableauEntry. FIXME: maybe remove this line. The basic variables will have a coefficient of 1 in the Tableau.

tableauInDictionaryForm :: Tableau -> Dict

Converts a Tableau to a Dict. We do this by isolating the basic variable on the LHS, ending up with all non basic variables and a SimplexNum constant on the RHS.

extractObjectiveValue :: Maybe Result -> Maybe SimplexNum

If this function is given Nothing, return Nothing. Otherwise, we lookup the Integer given in the first item of the pair in the map given in the second item of the pair. This is typically used to extract the value of the ObjectiveFunction after calling twoPhaseSimplex.

combineVarLitMapSums :: VarLitMapSum -> VarLitMapSum -> VarLitMapSum

Combines two 'VarLitMapSums together by summing values with matching keys

foldDictValue :: [DictValue] -> DictValue

foldVarLitMap :: [VarLitMap] -> VarLitMap

insertPivotObjectiveToDict :: PivotObjective -> Dict -> Dict

showT :: Show a => a -> Text

logMsg :: (MonadIO m, MonadLogger m) => LogLevel -> Text -> m ()

extractTableauValues :: Tableau -> Map Var SimplexNum

extractDictValues :: Dict -> Map Var SimplexNum