wip

Author: rasheedja

simplex-method.cabal

@@ -45,7 +45,6 @@ library
       Linear.SlackForm.Types
       Linear.SlackForm.Util
       Linear.System.Linear.Types
-      Linear.System.Linear.Util
       Linear.System.Simple.Types
       Linear.System.Simple.Util
       Linear.System.Types

src/Linear/Constraint/Linear/Util.hs

@@ -0,0 +1,17 @@
+-- |
+-- Module: Linear.Constraint.Linear.Util
+-- Description: Utility functions for linear constraints
+-- Copyright: (c) Junaid Rasheed, 2020-2024
+-- License: BSD-3
+-- Maintainer: Junaid Rasheed <jrasheed178@gmail.com>
+-- Stability: experimental
+module Linear.Constraint.Linear.Util where
+
+import Linear.Constraint.Linear.Types (LinearEquation (..))
+import Linear.Expr.Util ( exprVarsOnlyVars )
+import Linear.Var.Types ( Var )
+import qualified Data.Set as Set
+
+-- | Get the variables in a linear equation
+linearEquationVars :: LinearEquation -> Set.Set Var
+linearEquationVars (LinearEquation lhs _) = exprVarsOnlyVars lhs

src/Linear/SlackForm/Types.hs

@@ -7,18 +7,24 @@
 -- Stability: experimental
 module Linear.SlackForm.Types where
 
+import qualified Data.Set as Set
 import GHC.Generics (Generic)
-import Linear.Expr.Types (Expr)
+import Linear.Expr.Types (ExprVarsOnly)
 import Linear.System.Linear.Types (LinearSystem)
+import Linear.System.Simple.Types
 import Linear.Var.Types (SimplexNum, Var)
 
 -- Expr == SimplexNum
 data SlackForm = SlackForm
-  { maxObjective :: Expr -- TODO: should be ExprVarsOnly
+  { maxObjective :: ExprVarsOnly -- TODO: should be ExprVarsOnly
   , constraints :: LinearSystem
-  , vars :: [Var] -- all vars are non-negative
+  , vars :: Set.Set Var -- all vars are non-negative
   }
   deriving (Show, Eq, Read, Generic)
 
 class CanBeSlackForm a where
-  toSlackForm :: a -> SlackForm
+  -- TODO: CanBeExprVarsOnly
+  toSlackForm :: a -> ExprVarsOnly -> SlackForm
+
+instance CanBeSlackForm LinearSystem where
+  toSlackForm ls obj = SlackForm obj ls Set.empty