1 {-# LANGUAGE MultiParamTypeClasses, GADTs, FlexibleContexts, FlexibleInstances, TypeFamilies #-}
2 -----------------------------------------------------------------------------
4 -- Module : GArrowPortShape
6 -- License : public domain
8 -- Maintainer : Adam Megacz <megacz@acm.org>
9 -- Stability : experimental
11 -- | We cannot, at run time, query to find out the input and output
12 -- port types of a GArrowSkeleton since Haskell erases types during
13 -- compilation. Using Data.Typeable is problematic here because
14 -- GAS_comp and GAS_loop{l,r} have an existential type.
16 -- In spite of this, we can determine the "shape" of the ports --
17 -- which ports are of unit type, and which ports must be tensors. A
18 -- GArrowPortShape is a GArrowSkeleton along with this
19 -- information for certain nodes (the inference mechanism below adds
22 module GArrowPortShape (GArrowPortShape(..), PortShape(..))
24 import Prelude hiding ( id, (.), lookup )
25 import Control.Category
26 import GHC.HetMet.GArrow
29 import Control.Monad.State
32 -- | Please keep in mind that the "shapes" computed below are simply the
33 -- least-complicated shapes that could possibly work. Just because a
34 -- GArrowPortShape has an input port of shape (x,y)
35 -- doesn't mean it couldn't later be used in a context where its input
36 -- port had shape ((a,b),y)! However, you can be assured that it
37 -- won't be used in a context where the input port has shape ().
39 data PortShape a = PortUnit
40 | PortTensor (PortShape a) (PortShape a)
43 data GArrowPortShape m s a b =
51 (GArrowSkeleton (GArrowPortShape m s) a b)
54 -- implementation below; none of this is exported
57 type UPort = PortShape UVar
59 instance Unifiable UPort where
60 unify' (PortTensor x1 y1) (PortTensor x2 y2) = mergeU (unify x1 x2) (unify y1 y2)
61 unify' _ _ = error "impossible"
63 project (PortFree v) = Just v
65 occurrences (PortFree v) = [v]
66 occurrences (PortTensor x y) = occurrences x ++ occurrences y
67 occurrences PortUnit = []
70 type DetectM a = State ((Unifier UPort),[UVar]) a
72 shapes :: GArrowPortShape m UVar a b -> (UPort,UPort)
73 shapes (GASPortPassthrough x y _) = (x,y)
74 shapes (GASPortShapeWrapper x y _) = (x,y)
76 unifyM :: UPort -> UPort -> DetectM ()
77 unifyM p1 p2 = do { (u,vars) <- get
78 ; put (mergeU u $ unify p1 p2 , vars)
81 freshM :: DetectM UVar
82 freshM = do { (u,(v:vars)) <- get
87 -- recursive version of getU
88 getU' :: Unifier UPort -> UPort -> PortShape ()
89 getU' u (PortTensor x y) = PortTensor (getU' u x) (getU' u y)
90 getU' _ PortUnit = PortUnit
91 getU' u x@(PortFree v) = case Unify.getU u v of
92 Nothing -> PortFree () -- or x
95 resolveG :: Unifier UPort -> (GArrowPortShape m UVar a b) -> GArrowPortShape m () a b
96 resolveG u (GASPortPassthrough x y m) = GASPortPassthrough (getU' u x) (getU' u y) m
97 resolveG u (GASPortShapeWrapper x y g) = GASPortShapeWrapper (getU' u x) (getU' u y) (resolveG' g)
99 resolveG' :: GArrowSkeleton (GArrowPortShape m UVar) a b ->
100 GArrowSkeleton (GArrowPortShape m ()) a b
101 resolveG' (GAS_id ) = GAS_id
102 resolveG' (GAS_comp f g) = GAS_comp (resolveG' f) (resolveG' g)
103 resolveG' (GAS_first f) = GAS_first (resolveG' f)
104 resolveG' (GAS_second f) = GAS_second (resolveG' f)
105 resolveG' GAS_cancell = GAS_cancell
106 resolveG' GAS_cancelr = GAS_cancelr
107 resolveG' GAS_uncancell = GAS_uncancell
108 resolveG' GAS_uncancelr = GAS_uncancelr
109 resolveG' GAS_drop = GAS_drop
110 resolveG' (GAS_const i) = GAS_const i
111 resolveG' GAS_copy = GAS_copy
112 resolveG' GAS_merge = GAS_merge
113 resolveG' GAS_swap = GAS_swap
114 resolveG' GAS_assoc = GAS_assoc
115 resolveG' GAS_unassoc = GAS_unassoc
116 resolveG' (GAS_loopl f) = GAS_loopl (resolveG' f)
117 resolveG' (GAS_loopr f) = GAS_loopr (resolveG' f)
118 resolveG' (GAS_misc g ) = GAS_misc $ resolveG u g
120 runM :: DetectM (GArrowPortShape m UVar a b) -> GArrowPortShape m () a b
121 runM f = let s = (emptyUnifier,uvarSupply)
123 (u,_) = execState f s
126 detect :: GArrowSkeleton m a b -> DetectM (GArrowPortShape m UVar a b)
127 detect (GAS_id ) = do { x <- freshM ; return $ GASPortShapeWrapper (PortFree x) (PortFree x) GAS_id }
128 detect (GAS_comp g f) = do { f' <- detect f
130 ; unifyM (snd $ shapes f') (fst $ shapes g')
131 ; return $ GASPortShapeWrapper (fst $ shapes f') (snd $ shapes g') (GAS_comp (GAS_misc g') (GAS_misc f'))
133 detect (GAS_first f) = do { x <- freshM
135 ; return $ GASPortShapeWrapper
136 (PortTensor (fst $ shapes f') (PortFree x))
137 (PortTensor (snd $ shapes f') (PortFree x))
138 (GAS_first (GAS_misc f'))
140 detect (GAS_second f) = do { x <- freshM
142 ; return $ GASPortShapeWrapper
143 (PortTensor (PortFree x) (fst $ shapes f'))
144 (PortTensor (PortFree x) (snd $ shapes f'))
145 (GAS_second (GAS_misc f'))
147 detect GAS_cancell = do { x <- freshM; return$GASPortShapeWrapper (PortTensor PortUnit (PortFree x)) (PortFree x) GAS_cancell }
148 detect GAS_cancelr = do { x <- freshM; return$GASPortShapeWrapper (PortTensor (PortFree x) PortUnit) (PortFree x) GAS_cancelr }
149 detect GAS_uncancell = do { x <- freshM; return$GASPortShapeWrapper (PortFree x) (PortTensor PortUnit (PortFree x)) GAS_uncancell }
150 detect GAS_uncancelr = do { x <- freshM; return$GASPortShapeWrapper (PortFree x) (PortTensor (PortFree x) PortUnit) GAS_uncancelr }
151 detect GAS_drop = do { x <- freshM; return$GASPortShapeWrapper (PortFree x) PortUnit GAS_drop }
152 detect GAS_copy = do { x <- freshM
153 ; return $ GASPortShapeWrapper (PortFree x) (PortTensor (PortFree x) (PortFree x)) GAS_copy }
154 detect GAS_swap = do { x <- freshM
156 ; let x' = PortFree x
157 ; let y' = PortFree y
158 ; return $ GASPortShapeWrapper (PortTensor x' y') (PortTensor y' x') GAS_swap
160 detect GAS_assoc = do { x <- freshM; y <- freshM; z <- freshM
161 ; let x' = PortFree x
162 ; let y' = PortFree y
163 ; let z' = PortFree z
164 ; return $ GASPortShapeWrapper
165 (PortTensor (PortTensor x' y') z')
166 (PortTensor x' (PortTensor y' z'))
169 detect GAS_unassoc = do { x <- freshM; y <- freshM; z <- freshM
170 ; let x' = PortFree x
171 ; let y' = PortFree y
172 ; let z' = PortFree z
173 ; return $ GASPortShapeWrapper
174 (PortTensor x' (PortTensor y' z'))
175 (PortTensor (PortTensor x' y') z')
178 detect (GAS_const i) = do { x <- freshM; return $ GASPortShapeWrapper PortUnit (PortFree x) (GAS_const i) }
179 detect GAS_merge = do { x <- freshM
180 ; return $ GASPortShapeWrapper (PortTensor (PortFree x) (PortFree x)) (PortFree x) GAS_merge }
181 detect (GAS_loopl f) = error "not implemented"
182 detect (GAS_loopr f) = error "not implemented"
184 detect (GAS_misc f) = error "not implemented"