From 2bcc462368bce221a754fcbf6a90fd5cada5fa1e Mon Sep 17 00:00:00 2001
From: Francis Russell <francis@unchartedbackwaters.co.uk>
Date: Tue, 13 Nov 2012 19:27:05 +0000
Subject: [PATCH] Add function to determine theoretical bandwidth of
 expressions.

---
 OFC/SecondLevel.hs | 76 +++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 75 insertions(+), 1 deletion(-)

diff --git a/OFC/SecondLevel.hs b/OFC/SecondLevel.hs
index 97cc475..cde2b8f 100644
--- a/OFC/SecondLevel.hs
+++ b/OFC/SecondLevel.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE GADTs, EmptyDataDecls, StandaloneDeriving #-}
+{-# LANGUAGE FlexibleInstances, GADTs, EmptyDataDecls, StandaloneDeriving #-}
 
 module OFC.SecondLevel 
   ( SymbolTable
@@ -374,3 +374,77 @@ buildPositionOperator ofl ofl2 (TopLevel.Power a b) = (buildPositionOperator ofl
 buildPositionOperator _ _ (TopLevel.IndexedIdentifier name indices) = OpIndexedScalarIdentifier name indices
 buildPositionOperator _ _ (TopLevel.PositionComponent index) = OpTerminal $ PositionComponent index
 buildPositionOperator _ _ e = error $ "Unhandled expression: " ++ prettyPrint e
+
+-- Frequency fixup
+
+data Bandwidth =
+  GMaxMultiple Integer |
+  Infinite
+  deriving (Eq, Show)
+
+instance Ord Bandwidth where
+  compare (GMaxMultiple a) (GMaxMultiple b) = compare a b
+  compare (GMaxMultiple _) Infinite = LT
+  compare Infinite (GMaxMultiple _) = GT
+  compare Infinite Infinite = EQ
+
+instance Num Bandwidth where
+  (+) Infinite _ = Infinite
+  (+) _ Infinite = Infinite
+  (+) (GMaxMultiple a) (GMaxMultiple b) = GMaxMultiple $ a + b
+  (-) _ _ = error "Unimplemented: Bandwidth subtraction"
+  (*) _ _ = error "Unimplemented: Bandwidth multiplication"
+  abs _ = error "Unimplemnted: Bandwidth abs"
+  signum _ = error "Unimplemnted: Bandwidth signum"
+  fromInteger _ = error "Unimplemented: Bandwidth fromInteger"
+
+theoreticalFrequency :: OFL2 -> Expression e -> Bandwidth
+theoreticalFrequency ofl2 (IndexedPsincIdentifier ident _) = case getValueType ofl2 ident of
+  PositionT (Psinc i) -> GMaxMultiple i
+  _ -> error $ "Expected identifier " ++ ident ++ " to be a Psinc field."
+theoreticalFrequency _ (IndexedScalarIdentifier _ _) = GMaxMultiple 0
+theoreticalFrequency ofl2 (ToMomentum e) = theoreticalFrequency ofl2 e
+theoreticalFrequency ofl2 (ToPosition e) = theoreticalFrequency ofl2 e
+theoreticalFrequency ofl2 (Upsample e) = theoreticalFrequency ofl2 e
+theoreticalFrequency ofl2 (Downsample e) = theoreticalFrequency ofl2 e
+theoreticalFrequency _ (Integrate _) = GMaxMultiple 0
+theoreticalFrequency _ (AnalyticPosition _) = Infinite
+theoreticalFrequency _ (AnalyticMomentum _) = Infinite
+theoreticalFrequency ofl2 (AnalyticToPsinc e _) = theoreticalFrequency ofl2 e
+theoreticalFrequency ofl2 (Sum e _) = theoreticalFrequency ofl2 e
+theoreticalFrequency ofl2 (Add e1 e2) = max (theoreticalFrequency ofl2 e1) (theoreticalFrequency ofl2 e2)
+theoreticalFrequency ofl2 (Sub e1 e2) = max (theoreticalFrequency ofl2 e1) (theoreticalFrequency ofl2 e2)
+theoreticalFrequency ofl2 (Neg e) = theoreticalFrequency ofl2 e
+theoreticalFrequency ofl2 (MulScalar e _) = theoreticalFrequency ofl2 e
+theoreticalFrequency ofl2 (DivScalar e _) = theoreticalFrequency ofl2 e
+theoreticalFrequency ofl2 (PsincProduct a b) = (theoreticalFrequency ofl2 a) + (theoreticalFrequency ofl2 b)
+theoreticalFrequency ofl2 (PsincReciprocalProduct a b) = min (theoreticalFrequency ofl2 a) (theoreticalFrequency ofl2 b)
+theoreticalFrequency _ (ConstInteger _) = GMaxMultiple 0
+theoreticalFrequency _ (ConstReal _) = GMaxMultiple 0
+theoreticalFrequency _ (ConstComplex _) = GMaxMultiple 0
+theoreticalFrequency ofl2 (Power a b) = case (theoreticalFrequency ofl2 a, theoreticalFrequency ofl2 b) of
+  (GMaxMultiple 0, GMaxMultiple 0) -> GMaxMultiple 0
+  _ -> error "Expected power operator to be between scalars."
+
+-- fixScalarExpression :: OFL2 -> Expression ScalarE -> Expression ScalarE
+-- fixScalarExpression _ e@(IndexedScalarIdentifier _ _) = e
+-- fixScalarExpression ofl2 (Integrate f) = Integrate $ fixIntegrand ofl2 f
+-- fixScalarExpression ofl2 (Power a b) = Power (fixScalarExpression ofl2 a) (fixScalarExpression ofl2 b)
+-- fixScalarExpression ofl2 (Sum e index) = Sum (fixScalarExpression ofl2 e) index
+-- fixScalarExpression ofl2 (Add a b) = Add (fixScalarExpression ofl2 a) (fixScalarExpression ofl2 b)
+-- fixScalarExpression ofl2 (Sub a b) = Add (fixScalarExpression ofl2 a) (fixScalarExpression ofl2 b)
+-- fixScalarExpression ofl2 (Neg e) = Neg (fixScalarExpression ofl2 e)
+-- fixScalarExpression ofl2 (MulScalar a b) = Add (fixScalarExpression ofl2 a) (fixScalarExpression ofl2 b)
+-- fixScalarExpression ofl2 (DivScalar a b) = Add (fixScalarExpression ofl2 a) (fixScalarExpression ofl2 b)
+-- fixScalarExpression _ e@(ConstInteger _) = e
+-- fixScalarExpression _ e@(ConstReal _) = e
+-- fixScalarExpression _ e@(ConstComplex _) = e
+-- 
+-- fixIntegrand :: OFL2 -> Expression PsincE -> Expression PsincE
+-- fixIntegrand _ _ = error "Unimplemented"
+-- 
+-- fixPositionExpression :: OFL2 -> Expression PsincE -> Expression PsincE
+-- fixPositionExpression _ _  = error "Unimplemented"
+-- 
+-- fixMomentumExpression :: OFL2 -> Expression PsincReciprocalE -> Expression PsincReciprocalE
+-- fixMomentumExpression _ _  = error "Unimplemented"
-- 
2.47.3