tensorflow-haskell/tensorflow-ops/src/TensorFlow/Ops.hs

297 lines
10 KiB
Haskell

-- Copyright 2016 TensorFlow authors.
--
-- Licensed under the Apache License, Version 2.0 (the "License");
-- you may not use this file except in compliance with the License.
-- You may obtain a copy of the License at
--
-- http://www.apache.org/licenses/LICENSE-2.0
--
-- Unless required by applicable law or agreed to in writing, software
-- distributed under the License is distributed on an "AS IS" BASIS,
-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-- See the License for the specific language governing permissions and
-- limitations under the License.
-- | This module contains definitions for some built-in TensorFlow operations.
--
-- Note that certain, "stateful" ops like 'variable' and 'assign' return a
-- 'Build' action (e.g., @Build (Tensor Ref a)@ instead of a pure value; the
-- returned 'Tensor's are always rendered in the current 'Build' context. This
-- approach helps us avoid problems with inlining or common subexpression
-- elimination, by writing
--
-- > do
-- > v <- variable []
-- > w <- assign v 3
-- > render $ w * w
--
-- instead of
--
-- > let
-- > v = variable []
-- > w = assign v 3
-- > in w * w
--
-- since the latter could be reasonably transformed by the compiler into (or
-- vice versa)
--
-- > let
-- > v = variable []
-- > w = assign v 3
-- > w' = assign v 3
-- > in w * w'
--
-- Ops should return a 'Build' action if their original 'OpDef' marks them as
-- stateful, or if they take any Refs as input. (This mirrors the rules that
-- TensorFlow uses to avoid common subexpression elimination.)
{-# LANGUAGE ConstraintKinds #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE OverloadedLists #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE UndecidableInstances #-}
{-# OPTIONS_GHC -fno-warn-orphans #-}
module TensorFlow.Ops
( CoreOps.add
, CoreOps.abs
, CoreOps.addN
, CoreOps.argMax
, assign
, CoreOps.broadcastGradientArgs
, CoreOps.cast
, CoreOps.concat
, constant
, expandDims
, initializedVariable
, zeroInitializedVariable
, CoreOps.fill
, CoreOps.matMul
, matTranspose
, CoreOps.mul
, CoreOps.neg
, CoreOps.pack
, placeholder
, CoreOps.range
, reducedShape
, CoreOps.relu
, CoreOps.reluGrad
, CoreOps.reshape
, restore
, restoreFromName
, save
, scalar
, shape
, CoreOps.sign
, CoreOps.size
, CoreOps.softmax
, CoreOps.softmaxCrossEntropyWithLogits
, CoreOps.sparseToDense
, CoreOps.sub
, CoreOps.sum
, CoreOps.topK
, CoreOps.transpose
, truncatedNormal
, variable
, vector
, zeros
, CoreOps.zerosLike
) where
import Data.ByteString (ByteString)
import Data.Complex (Complex)
import Data.Int (Int32, Int64)
import Prelude hiding (abs, sum, concat)
import Data.ProtoLens (def)
import Data.Text.Encoding (encodeUtf8)
import Lens.Family2 ((.~), (&))
import Text.Printf (printf)
import Proto.Tensorflow.Core.Framework.Tensor
( TensorProto
, dtype
, tensorShape
)
import qualified Proto.Tensorflow.Core.Framework.TensorShape
as TensorShape
import TensorFlow.Build
import TensorFlow.BuildOp
import TensorFlow.ControlFlow (group)
import TensorFlow.Output (unNodeName)
import TensorFlow.Tensor
import TensorFlow.Types
import qualified TensorFlow.GenOps.Core as CoreOps
import qualified Prelude (abs)
-- TODO: Look into hs-boot refactoring to allow mutually recursive imports.
-- | Must be defined as an orphan because of the dependency order between Ops
-- and Tensor.
--
-- The indirect constraint "v ~ Value" helps disambiguate types, for example in
-- "neg 1 :: Tensor Value Float", it helps find the type of the subexpression
-- "1".
instance ( TensorType a
, Num a
, v ~ Value
, OneOf '[ Double, Float, Int32, Int64
, Complex Float, Complex Double] a) => Num (Tensor v a) where
(+) = CoreOps.add
(*) = CoreOps.mul
(-) = CoreOps.sub
abs = CoreOps.abs
fromInteger = scalar . fromInteger
signum = CoreOps.sign
negate = CoreOps.neg
matTranspose :: forall a v . TensorType a
=> Tensor v a -> Tensor Value a
matTranspose = flip CoreOps.transpose (vector [1, 0 :: Int32])
-- | Create a new, uninitialized stateful Tensor of the given shape.
variable :: forall a . TensorType a => Shape -> Build (Tensor Ref a)
variable shape' = buildOp $ opDef "Variable"
& opAttr "shape" .~ shape'
& opAttr "dtype" .~ tensorType (undefined :: a)
placeholder :: forall a . TensorType a => Shape -> Build (Tensor Value a)
placeholder shape' =
buildOp $ opDef "Placeholder"
& opAttr "dtype" .~ tensorType (undefined :: a)
& opAttr "shape" .~ shape'
-- Assign returns the input ref.
assign :: forall a v . TensorType a
=> Tensor Ref a -> Tensor v a -> Build (Tensor Ref a)
assign = buildOp $ opDef "Assign"
& opAttr "T" .~ tensorType (undefined :: a)
& opAttr "use_locking" .~ True
-- | Creates a variable initialized to the given value.
-- Initialization happens next time session runs.
initializedVariable :: forall a . TensorType a
=> Tensor Value a -> Build (Tensor Ref a)
initializedVariable initializer = do
v <- variable [] -- The shape is not known initially.
(i :: Tensor Ref a) <-
buildOp (opDef "Assign"
& opAttr "T" .~ tensorType (undefined :: a)
& opAttr "use_locking" .~ True
& opAttr "validate_shape" .~ False
)
v initializer
addInitializer =<< group i
return v
-- | Creates a zero-initialized variable with the given shape.
zeroInitializedVariable
:: (TensorType a, Num a) =>
TensorFlow.Types.Shape -> Build (Tensor TensorFlow.Tensor.Ref a)
zeroInitializedVariable = initializedVariable . zeros
-- TODO: Support heterogeneous list of tensors.
save :: forall a v . TensorType a
=> ByteString -- ^ File path.
-> [Tensor v a] -- ^ Tensors to save.
-> Build ControlNode
save path xs = do
let toByteStringTensor = scalar . encodeUtf8 . unNodeName
names <- mapM (fmap toByteStringTensor . renderNodeName) xs
let types = replicate (length xs) (tensorType (undefined :: a))
let saveOp = buildOp $ opDef "Save"
& opAttr "T" .~ types
saveOp (scalar path) (CoreOps.pack names) xs
-- | Restore a tensor's value from a checkpoint file.
--
-- This version allows restoring from a checkpoint file that uses a different
-- tensor name than the variable.
restoreFromName :: forall a . TensorType a
=> ByteString -- ^ File path.
-> ByteString -- ^ Tensor name override.
-> Tensor Ref a -- ^ Tensor to restore.
-> Build ControlNode
restoreFromName path name x = do
let restoreOp = buildOp $ opDef "Restore"
& opAttr "dt" .~ tensorType (undefined :: a)
group =<< assign x (restoreOp (scalar path) (scalar name) :: Tensor Value a)
-- | Restore a tensor's value from a checkpoint file.
restore :: forall a . TensorType a
=> ByteString -- ^ File path.
-> Tensor Ref a -- ^ Tensor to restore.
-> Build ControlNode
restore path x = do
name <- encodeUtf8 . unNodeName <$> renderNodeName x
restoreFromName path name x
-- | Create a constant tensor.
--
-- The values should be in row major order, e.g.,
--
-- element 0: index (0, ..., 0)
-- element 1: index (0, ..., 1)
-- ...
constant :: forall a . TensorType a => Shape -> [a] -> Tensor Value a
constant (Shape shape') values
| invalidLength = error invalidLengthMsg
| otherwise = buildOp $ opDef "Const"
& opAttr "value" .~ typedNode
& opAttr "dtype" .~ nodeType
where
invalidLength = product shape' /= fromIntegral (length values)
invalidLengthMsg = printf "invalid tensor length: expected %d got %d"
(product shape')
(length values)
nodeType = tensorType (undefined :: a)
typedNode :: TensorProto
typedNode = def
& dtype .~ nodeType
& tensorShape.TensorShape.dim .~
[def & TensorShape.size .~ x | x <- shape']
& tensorVal .~ values
-- | Create a constant vector.
vector :: TensorType a => [a] -> Tensor Value a
vector xs = constant [fromIntegral $ length xs] xs
-- | Create a constant scalar.
scalar :: forall a . TensorType a => a -> Tensor Value a
scalar x = constant [] [x]
-- Random tensor from the unit normal distribution with bounded values.
truncatedNormal :: forall a v . TensorType a
=> Tensor v Int64 -- ^ Shape.
-> Build (Tensor Value a)
truncatedNormal = buildOp $ opDef "TruncatedNormal"
& opAttr "dtype" .~ tensorType (undefined :: a)
& opAttr "T" .~ tensorType (undefined :: Int64)
zeros :: forall a . (Num a, TensorType a) => Shape -> Tensor Value a
zeros (Shape shape') = CoreOps.fill (vector $ map fromIntegral shape') (scalar 0)
shape :: (TensorType t) => Tensor v1 t -> Tensor Value Int32
shape = CoreOps.shape
expandDims :: (TensorType t) => Tensor v1 t -> Tensor v2 Int32 -> Tensor Value t
expandDims = CoreOps.expandDims
-- | Helper function for reduction ops (translation of math_ops.reduced_shape).
reducedShape :: (OneOf '[ Int32, Int64 ] t1, OneOf '[ Int32, Int64 ] t2) =>
Tensor v1 t1 -> Tensor v2 t2 -> Tensor Value Int32
reducedShape inputShape axes =
let inputShape32 = toInt32 inputShape -- [2, 3, 5, 7]
axes32 = toInt32 axes -- [1, 2]
toInt32 x = CoreOps.cast x :: Tensor Value Int32
inputRank = CoreOps.size inputShape32 -- 4
axesMod = (axes32 + inputRank) `CoreOps.mod` inputRank
axesShape = shape axesMod -- [2]
in CoreOps.dynamicStitch -- [2, 1, 1, 7]
[CoreOps.range 0 inputRank 1, -- [0, 1, 2, 3]
axesMod] -- [1, 2]
[inputShape32, -- [2, 3, 5, 7]
CoreOps.fill axesShape 1] -- [1, 1]