fm

Author: rasheedja

src/Linear/Constraint/Linear/Util.hs

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+-- |
+-- Module: Linear.Constraint.Linear.Util
+-- Description: Utility functions for linear constraints
+-- Copyright: (c) Junaid Rasheed, 2024
+-- License: BSD-3
+-- Maintainer: Junaid Rasheed <jrasheed178@gmail.com>
+-- Stability: experimental
+module Linear.Constraint.Linear.Util where
+
+import qualified Data.Set as Set
+import Linear.Constraint.Linear.Types (LinearEquation (..))
+import Linear.Expr.Types (ExprVarsOnly)
+import Linear.Expr.Util
+  ( exprVarsOnlyMaxVar
+  , exprVarsOnlyVars
+  , substVarExprVarsOnly
+  )
+import Linear.Var.Types (Var)
+
+-- | Get the variables in a linear equation
+linearEquationVars :: LinearEquation -> Set.Set Var
+linearEquationVars (LinearEquation lhs _) = exprVarsOnlyVars lhs
+
+findHighestVar :: LinearEquation -> Var
+findHighestVar (LinearEquation lhs _) = exprVarsOnlyMaxVar lhs
+
+substVarWith ::
+  Var -> ExprVarsOnly -> LinearEquation -> LinearEquation
+substVarWith var expr (LinearEquation lhs rhs) = LinearEquation (substVarExprVarsOnly var expr lhs) rhs