| Copyright | (c) Justin Le 2018 |
|---|---|
| License | BSD3 |
| Maintainer | justin@jle.im |
| Stability | experimental |
| Portability | non-portable |
| Safe Haskell | None |
| Language | Haskell2010 |
Numeric.Backprop.Explicit
Contents
Description
Provides "explicit" versions of all of the functions in
Numeric.Backprop. Instead of relying on a Backprop instance, allows
you to manually provide zero, add, and one on a per-value basis.
It is recommended you use Numeric.Backprop or Numeric.Backprop.Num
instead, unless your type has no Num instance, or you else you want to
avoid defining orphan Backprop instances for external types. Can also
be useful if mixing and matching styles.
See Numeric.Backprop for fuller documentation on using these functions.
WARNING: API of this module can be considered only "semi-stable"; while the API of Numeric.Backprop and Numeric.Backprop.Num are kept consistent, some argument order changes might happen in this module to reflect changes in underlying implementation.
Since: 0.2.0.0
- data BVar s a
- data W
- class Backprop a where
- newtype ABP f a = ABP {
- runABP :: f a
- newtype NumBP a = NumBP {
- runNumBP :: a
- newtype ZeroFunc a = ZF {
- runZF :: a -> a
- zfNum :: Num a => ZeroFunc a
- zfNums :: (Every Num as, Known Length as) => Prod ZeroFunc as
- zeroFunc :: Backprop a => ZeroFunc a
- zeroFuncs :: (Every Backprop as, Known Length as) => Prod ZeroFunc as
- zfFunctor :: (Backprop a, Functor f) => ZeroFunc (f a)
- newtype AddFunc a = AF {
- runAF :: a -> a -> a
- afNum :: Num a => AddFunc a
- afNums :: (Every Num as, Known Length as) => Prod AddFunc as
- addFunc :: Backprop a => AddFunc a
- addFuncs :: (Every Backprop as, Known Length as) => Prod AddFunc as
- newtype OneFunc a = OF {
- runOF :: a -> a
- ofNum :: Num a => OneFunc a
- ofNums :: (Every Num as, Known Length as) => Prod OneFunc as
- oneFunc :: Backprop a => OneFunc a
- oneFuncs :: (Every Backprop as, Known Length as) => Prod OneFunc as
- ofFunctor :: (Backprop a, Functor f) => OneFunc (f a)
- backprop :: ZeroFunc a -> OneFunc b -> (forall s. Reifies s W => BVar s a -> BVar s b) -> a -> (b, a)
- evalBP :: (forall s. Reifies s W => BVar s a -> BVar s b) -> a -> b
- gradBP :: ZeroFunc a -> OneFunc b -> (forall s. Reifies s W => BVar s a -> BVar s b) -> a -> a
- backpropWith :: ZeroFunc a -> (forall s. Reifies s W => BVar s a -> BVar s b) -> a -> (b, b -> a)
- evalBP0 :: (forall s. Reifies s W => BVar s a) -> a
- backprop2 :: ZeroFunc a -> ZeroFunc b -> OneFunc c -> (forall s. Reifies s W => BVar s a -> BVar s b -> BVar s c) -> a -> b -> (c, (a, b))
- evalBP2 :: (forall s. Reifies s W => BVar s a -> BVar s b -> BVar s c) -> a -> b -> c
- gradBP2 :: ZeroFunc a -> ZeroFunc b -> OneFunc c -> (forall s. Reifies s W => BVar s a -> BVar s b -> BVar s c) -> a -> b -> (a, b)
- backpropWith2 :: ZeroFunc a -> ZeroFunc b -> (forall s. Reifies s W => BVar s a -> BVar s b -> BVar s c) -> a -> b -> (c, c -> (a, b))
- backpropN :: forall as b. Prod ZeroFunc as -> OneFunc b -> (forall s. Reifies s W => Prod (BVar s) as -> BVar s b) -> Tuple as -> (b, Tuple as)
- evalBPN :: forall as b. (forall s. Reifies s W => Prod (BVar s) as -> BVar s b) -> Tuple as -> b
- gradBPN :: Prod ZeroFunc as -> OneFunc b -> (forall s. Reifies s W => Prod (BVar s) as -> BVar s b) -> Tuple as -> Tuple as
- backpropWithN :: forall as b. Prod ZeroFunc as -> (forall s. Reifies s W => Prod (BVar s) as -> BVar s b) -> Tuple as -> (b, b -> Tuple as)
- class EveryC k c as => Every k (c :: k -> Constraint) (as :: [k])
- constVar :: a -> BVar s a
- auto :: a -> BVar s a
- coerceVar :: Coercible a b => BVar s a -> BVar s b
- viewVar :: forall a b s. Reifies s W => AddFunc a -> ZeroFunc b -> Lens' b a -> BVar s b -> BVar s a
- setVar :: forall a b s. Reifies s W => AddFunc a -> AddFunc b -> ZeroFunc a -> Lens' b a -> BVar s a -> BVar s b -> BVar s b
- overVar :: Reifies s W => AddFunc a -> AddFunc b -> ZeroFunc a -> ZeroFunc b -> Lens' b a -> (BVar s a -> BVar s a) -> BVar s b -> BVar s b
- sequenceVar :: forall t a s. (Reifies s W, Traversable t) => AddFunc a -> ZeroFunc a -> BVar s (t a) -> t (BVar s a)
- collectVar :: forall t a s. (Reifies s W, Foldable t, Functor t) => AddFunc a -> ZeroFunc a -> t (BVar s a) -> BVar s (t a)
- previewVar :: forall b a s. Reifies s W => AddFunc a -> ZeroFunc b -> Traversal' b a -> BVar s b -> Maybe (BVar s a)
- toListOfVar :: forall b a s. Reifies s W => AddFunc a -> ZeroFunc b -> Traversal' b a -> BVar s b -> [BVar s a]
- isoVar :: Reifies s W => AddFunc a -> (a -> b) -> (b -> a) -> BVar s a -> BVar s b
- isoVar2 :: Reifies s W => AddFunc a -> AddFunc b -> (a -> b -> c) -> (c -> (a, b)) -> BVar s a -> BVar s b -> BVar s c
- isoVar3 :: Reifies s W => AddFunc a -> AddFunc b -> AddFunc c -> (a -> b -> c -> d) -> (d -> (a, b, c)) -> BVar s a -> BVar s b -> BVar s c -> BVar s d
- isoVarN :: Reifies s W => Prod AddFunc as -> (Tuple as -> b) -> (b -> Tuple as) -> Prod (BVar s) as -> BVar s b
- liftOp :: forall as b s. Reifies s W => Prod AddFunc as -> Op as b -> Prod (BVar s) as -> BVar s b
- liftOp1 :: forall a b s. Reifies s W => AddFunc a -> Op '[a] b -> BVar s a -> BVar s b
- liftOp2 :: forall a b c s. Reifies s W => AddFunc a -> AddFunc b -> Op '[a, b] c -> BVar s a -> BVar s b -> BVar s c
- liftOp3 :: forall a b c d s. Reifies s W => AddFunc a -> AddFunc b -> AddFunc c -> Op '[a, b, c] d -> BVar s a -> BVar s b -> BVar s c -> BVar s d
- splitBV :: forall z f s as. (Generic (z f), Generic (z (BVar s)), BVGroup s as (Rep (z f)) (Rep (z (BVar s))), Reifies s W) => AddFunc (Rep (z f) ()) -> Prod AddFunc as -> ZeroFunc (z f) -> Prod ZeroFunc as -> BVar s (z f) -> z (BVar s)
- joinBV :: forall z f s as. (Generic (z f), Generic (z (BVar s)), BVGroup s as (Rep (z f)) (Rep (z (BVar s))), Reifies s W) => AddFunc (z f) -> Prod AddFunc as -> ZeroFunc (Rep (z f) ()) -> Prod ZeroFunc as -> z (BVar s) -> BVar s (z f)
- class BVGroup s as i o | o -> i, i -> as
- newtype Op as a = Op {}
- op0 :: a -> Op '[] a
- opConst :: (Every Num as, Known Length as) => a -> Op as a
- idOp :: Op '[a] a
- opConst' :: Every Num as => Length as -> a -> Op as a
- op1 :: (a -> (b, b -> a)) -> Op '[a] b
- op2 :: (a -> b -> (c, c -> (a, b))) -> Op '[a, b] c
- op3 :: (a -> b -> c -> (d, d -> (a, b, c))) -> Op '[a, b, c] d
- opCoerce :: Coercible a b => Op '[a] b
- opTup :: Op as (Tuple as)
- opIso :: (a -> b) -> (b -> a) -> Op '[a] b
- opIsoN :: (Tuple as -> b) -> (b -> Tuple as) -> Op as b
- opLens :: Num a => Lens' a b -> Op '[a] b
- noGrad1 :: (a -> b) -> Op '[a] b
- noGrad :: (Tuple as -> b) -> Op as b
- data Prod k (f :: k -> *) (a :: [k]) :: forall k. (k -> *) -> [k] -> * where
- pattern (:>) :: forall k (f :: k -> *) (a :: k) (b :: k). f a -> f b -> Prod k f ((:) k a ((:) k b ([] k)))
- only :: f a -> Prod k f ((:) k a ([] k))
- head' :: Prod k f ((:<) k a as) -> f a
- type Tuple = Prod * I
- pattern (::<) :: forall a (as :: [*]). a -> Tuple as -> Tuple ((:<) * a as)
- only_ :: a -> Tuple ((:) * a ([] *))
- newtype I a :: * -> * = I {
- getI :: a
- class Reifies k (s :: k) a | s -> a
Types
A is a value of type BVar s aa that can be "backpropagated".
Functions referring to BVars are tracked by the library and can be
automatically differentiated to get their gradients and results.
For simple numeric values, you can use its Num, Fractional, and
Floating instances to manipulate them as if they were the numbers they
represent.
If a contains items, the items can be accessed and extracted using
lenses. A can be used to access an Lens' b aa inside a b, using
^^. (viewVar):
(^.) :: a ->Lens'a b -> b (^^.) ::BVars a ->Lens'a b ->BVars b
There is also ^^? (previewVar), to use a Prism'
or Traversal' to extract a target that may or may not be present
(which can implement pattern matching), ^^..
(toListOfVar) to use a Traversal' to extract all
targets inside a BVar, and .~~ (setVar) to set and update values
inside a BVar.
If you have control over your data type definitions, you can also use
splitBV and joinBV to manipulate
data types by easily extracting fields out of a BVar of data types and
creating BVars of data types out of BVars of their fields. See
Numeric.Backprop for a tutorial on this use pattern.
For more complex operations, libraries can provide functions on BVars
using liftOp and related functions. This is how you
can create primitive functions that users can use to manipulate your
library's values. See
https://backprop.jle.im/08-equipping-your-library.html for a detailed
guide.
For example, the hmatrix library has a matrix-vector multiplication
function, #> :: L m n -> R n -> L m.
A library could instead provide a function #> :: , which the user can then use to manipulate their
BVar (L m n) -> BVar
(R n) -> BVar (R m)BVars of L m ns and R ns, etc.
See Numeric.Backprop and documentation for
liftOp for more information.
Instances
| BVGroup s ([] *) (K1 * i a) (K1 * i (BVar s a)) Source # | |
| Eq a => Eq (BVar s a) Source # | Compares the values inside the Since: 0.1.5.0 |
| (Floating a, Reifies Type s W) => Floating (BVar s a) Source # | |
| (Fractional a, Reifies Type s W) => Fractional (BVar s a) Source # | |
| (Num a, Reifies Type s W) => Num (BVar s a) Source # | |
| Ord a => Ord (BVar s a) Source # | Compares the values inside the Since: 0.1.5.0 |
| NFData a => NFData (BVar s a) Source # | This will force the value inside, as well. |
| (Backprop a, Reifies Type s W) => Backprop (BVar s a) Source # | Since: 0.2.2.0 |
class Backprop a where Source #
Class of values that can be backpropagated in general.
For instances of Num, these methods can be given by zeroNum,
addNum, and oneNum. There are also generic options given in
Numeric.Backprop.Class for functors, IsList instances, and Generic
instances.
instanceBackpropDoublewherezero=zeroNumadd=addNumone=oneNum
If you leave the body of an instance declaration blank, GHC Generics
will be used to derive instances if the type has a single constructor
and each field is an instance of Backprop.
To ensure that backpropagation works in a sound way, should obey the laws:
- identity
Also implies preservation of information, making an
illegal implementation for lists and vectors.zipWith (+)
This is only expected to be true up to potential "extra zeroes" in x
and y in the result.
- commutativity
- associativity
- idempotence
- unital
Note that not all values in the backpropagation process needs all of
these methods: Only the "final result" needs one, for example. These
are all grouped under one typeclass for convenience in defining
instances, and also to talk about sensible laws. For fine-grained
control, use the "explicit" versions of library functions (for example,
in Numeric.Backprop.Explicit) instead of Backprop based ones.
This typeclass replaces the reliance on Num of the previous API
(v0.1). Num is strictly more powerful than Backprop, and is
a stronger constraint on types than is necessary for proper
backpropagating. In particular, fromInteger is a problem for many
types, preventing useful backpropagation for lists, variable-length
vectors (like Data.Vector) and variable-size matrices from linear
algebra libraries like hmatrix and accelerate.
Since: 0.2.0.0
Methods
"Zero out" all components of a value. For scalar values, this
should just be . For vectors and matrices, this should
set all components to zero, the additive identity.const 0
Should be idempotent:
Should be as lazy as possible. This behavior is observed for all instances provided by this library.
See zeroNum for a pre-built definition for instances of Num and
zeroFunctor for a definition for instances of Functor. If left
blank, will automatically be genericZero, a pre-built definition
for instances of Generic whose fields are all themselves
instances of Backprop.
Add together two values of a type. To combine contributions of gradients, so should be information-preserving:
Should be as strict as possible. This behavior is observed for all instances provided by this library.
See addNum for a pre-built definition for instances of Num and
addIsList for a definition for instances of IsList. If left
blank, will automatically be genericAdd, a pre-built definition
for instances of Generic with one constructor whose fields are
all themselves instances of Backprop.
One all components of a value. For scalar values, this should
just be . For vectors and matrices, this should set all
components to one, the multiplicative identity.const 1
As the library uses it, the most important law is:
That is, is the gradient of the identity function with
respect to its input.one x
Ideally should be idempotent:
Should be as lazy as possible. This behavior is observed for all instances provided by this library.
See oneNum for a pre-built definition for instances of Num and
oneFunctor for a definition for instances of Functor. If left
blank, will automatically be genericOne, a pre-built definition
for instances of Generic whose fields are all themselves
instances of Backprop.
zero :: (Generic a, GZero (Rep a)) => a -> a Source #
"Zero out" all components of a value. For scalar values, this
should just be . For vectors and matrices, this should
set all components to zero, the additive identity.const 0
Should be idempotent:
Should be as lazy as possible. This behavior is observed for all instances provided by this library.
See zeroNum for a pre-built definition for instances of Num and
zeroFunctor for a definition for instances of Functor. If left
blank, will automatically be genericZero, a pre-built definition
for instances of Generic whose fields are all themselves
instances of Backprop.
add :: (Generic a, GAdd (Rep a)) => a -> a -> a Source #
Add together two values of a type. To combine contributions of gradients, so should be information-preserving:
Should be as strict as possible. This behavior is observed for all instances provided by this library.
See addNum for a pre-built definition for instances of Num and
addIsList for a definition for instances of IsList. If left
blank, will automatically be genericAdd, a pre-built definition
for instances of Generic with one constructor whose fields are
all themselves instances of Backprop.
one :: (Generic a, GOne (Rep a)) => a -> a Source #
One all components of a value. For scalar values, this should
just be . For vectors and matrices, this should set all
components to one, the multiplicative identity.const 1
As the library uses it, the most important law is:
That is, is the gradient of the identity function with
respect to its input.one x
Ideally should be idempotent:
Should be as lazy as possible. This behavior is observed for all instances provided by this library.
See oneNum for a pre-built definition for instances of Num and
oneFunctor for a definition for instances of Functor. If left
blank, will automatically be genericOne, a pre-built definition
for instances of Generic whose fields are all themselves
instances of Backprop.
Instances
| Backprop Double Source # | |
| Backprop Float Source # | |
| Backprop Int Source # | |
| Backprop Integer Source # | |
| Backprop Natural Source # | Since: 0.2.1.0 |
| Backprop Word Source # | Since: 0.2.2.0 |
| Backprop Word8 Source # | Since: 0.2.2.0 |
| Backprop Word16 Source # | Since: 0.2.2.0 |
| Backprop Word32 Source # | Since: 0.2.2.0 |
| Backprop Word64 Source # | Since: 0.2.2.0 |
| Backprop () Source # |
|
| Backprop Void Source # | |
| Backprop Expr Source # | Since: 0.2.4.0 |
| Backprop a => Backprop [a] Source # |
|
| Backprop a => Backprop (Maybe a) Source # |
|
| Integral a => Backprop (Ratio a) Source # | |
| RealFloat a => Backprop (Complex a) Source # | |
| Backprop a => Backprop (First a) Source # | Since: 0.2.2.0 |
| Backprop a => Backprop (Last a) Source # | Since: 0.2.2.0 |
| Backprop a => Backprop (Option a) Source # | Since: 0.2.2.0 |
| Backprop a => Backprop (NonEmpty a) Source # |
|
| Backprop a => Backprop (Identity a) Source # | |
| Backprop a => Backprop (Dual a) Source # | Since: 0.2.2.0 |
| Backprop a => Backprop (Sum a) Source # | Since: 0.2.2.0 |
| Backprop a => Backprop (Product a) Source # | Since: 0.2.2.0 |
| Backprop a => Backprop (First a) Source # | Since: 0.2.2.0 |
| Backprop a => Backprop (Last a) Source # | Since: 0.2.2.0 |
| Backprop a => Backprop (IntMap a) Source # |
|
| Backprop a => Backprop (Seq a) Source # |
|
| Backprop a => Backprop (I a) Source # | |
| (Unbox a, Backprop a) => Backprop (Vector a) Source # | |
| (Storable a, Backprop a) => Backprop (Vector a) Source # | |
| (Prim a, Backprop a) => Backprop (Vector a) Source # | |
| Backprop a => Backprop (Vector a) Source # | |
| Num a => Backprop (NumBP a) Source # | |
| Backprop a => Backprop (r -> a) Source # |
Since: 0.2.2.0 |
| Backprop (V1 * p) Source # | Since: 0.2.2.0 |
| Backprop (U1 * p) Source # | Since: 0.2.2.0 |
| (Backprop a, Backprop b) => Backprop (a, b) Source # |
|
| (Backprop a, Backprop b) => Backprop (Arg a b) Source # | Since: 0.2.2.0 |
| Backprop (Proxy * a) Source # | |
| (Backprop a, Ord k) => Backprop (Map k a) Source # |
|
| (Applicative f, Backprop a) => Backprop (ABP f a) Source # | |
| (Vector v a, Num a) => Backprop (NumVec v a) Source # | |
| (Backprop a, Reifies Type s W) => Backprop (BVar s a) Source # | Since: 0.2.2.0 |
| (Backprop a, Backprop b, Backprop c) => Backprop (a, b, c) Source # |
|
| (Backprop a, Applicative m) => Backprop (Kleisli m r a) Source # | Since: 0.2.2.0 |
| Backprop w => Backprop (Const * w a) Source # | Since: 0.2.2.0 |
| ListC ((<$>) * Constraint Backprop ((<$>) * * f as)) => Backprop (Prod * f as) Source # | |
| Backprop w => Backprop (C * w a) Source # | Since: 0.2.2.0 |
| Backprop (f a a) => Backprop (Join * f a) Source # | Since: 0.2.2.0 |
| MaybeC ((<$>) * Constraint Backprop ((<$>) * * f a)) => Backprop (Option * f a) Source # | |
| Backprop a => Backprop (K1 * i a p) Source # | Since: 0.2.2.0 |
| (Backprop (f p), Backprop (g p)) => Backprop ((:*:) * f g p) Source # | Since: 0.2.2.0 |
| (Backprop a, Backprop b, Backprop c, Backprop d) => Backprop (a, b, c, d) Source # |
|
| (Backprop (f a), Backprop (g a)) => Backprop (Product * f g a) Source # | Since: 0.2.2.0 |
| Backprop (p a b) => Backprop (Uncur * * p ((,) * * a b)) Source # | Since: 0.2.2.0 |
| (Backprop (f a), Backprop (g a)) => Backprop ((:&:) * f g a) Source # | Since: 0.2.2.0 |
| Backprop (f p) => Backprop (M1 * i c f p) Source # | Since: 0.2.2.0 |
| (Backprop a, Backprop b, Backprop c, Backprop d, Backprop e) => Backprop (a, b, c, d, e) Source # |
|
| Backprop (f (g a)) => Backprop (Compose * * f g a) Source # | Since: 0.2.2.0 |
| Backprop (f (g a)) => Backprop ((:.:) * * f g a) Source # | Since: 0.2.2.0 |
| Backprop (p a b) => Backprop (Flip * * p b a) Source # | Since: 0.2.2.0 |
| Backprop (p ((,) * * a b)) => Backprop (Cur * * p a b) Source # | Since: 0.2.2.0 |
| Backprop (p a b c) => Backprop (Uncur3 * * * p ((,,) * * * a b c)) Source # | Since: 0.2.2.0 |
| Backprop (c (f a)) => Backprop (LL * * c a f) Source # | Since: 0.2.2.0 |
| Backprop (c (f a)) => Backprop (RR * * c f a) Source # | Since: 0.2.2.0 |
| (Backprop (f a), Backprop (g b)) => Backprop ((:*:) * * f g ((,) * * a b)) Source # | Since: 0.2.2.0 |
| Backprop (f (g h) a) => Backprop (Comp1 * * * f g h a) Source # | Since: 0.2.2.0 |
| Backprop (p ((,,) * * * a b c)) => Backprop (Cur3 * * * p a b c) Source # | Since: 0.2.2.0 |
| Backprop (t (Flip * * f b) a) => Backprop (Conj * * * t f a b) Source # | Since: 0.2.2.0 |
A newtype wrapper over an f a for that gives
a free Applicative fBackprop instance (as well as Num etc. instances).
Useful for performing backpropagation over functions that require some
monadic context (like IO) to perform.
Since: 0.2.1.0
Instances
| Monad f => Monad (ABP f) Source # | |
| Functor f => Functor (ABP f) Source # | |
| Applicative f => Applicative (ABP f) Source # | |
| Foldable f => Foldable (ABP f) Source # | |
| Traversable f => Traversable (ABP f) Source # | |
| Alternative f => Alternative (ABP f) Source # | |
| MonadPlus f => MonadPlus (ABP f) Source # | |
| Eq (f a) => Eq (ABP f a) Source # | |
| (Applicative f, Floating a) => Floating (ABP f a) Source # | |
| (Applicative f, Fractional a) => Fractional (ABP f a) Source # | |
| (Data (f a), Typeable * a, Typeable (* -> *) f) => Data (ABP f a) Source # | |
| (Applicative f, Num a) => Num (ABP f a) Source # | |
| Ord (f a) => Ord (ABP f a) Source # | |
| Read (f a) => Read (ABP f a) Source # | |
| Show (f a) => Show (ABP f a) Source # | |
| Generic (ABP f a) Source # | |
| NFData (f a) => NFData (ABP f a) Source # | |
| (Applicative f, Backprop a) => Backprop (ABP f a) Source # | |
| type Rep (ABP f a) Source # | |
A newtype wrapper over an instance of Num that gives a free
Backprop instance.
Useful for things like DerivingVia, or for avoiding orphan instances.
Since: 0.2.1.0
Instances
| Monad NumBP Source # | |
| Functor NumBP Source # | |
| Applicative NumBP Source # | |
| Foldable NumBP Source # | |
| Traversable NumBP Source # | |
| Eq a => Eq (NumBP a) Source # | |
| Floating a => Floating (NumBP a) Source # | |
| Fractional a => Fractional (NumBP a) Source # | |
| Data a => Data (NumBP a) Source # | |
| Num a => Num (NumBP a) Source # | |
| Ord a => Ord (NumBP a) Source # | |
| Read a => Read (NumBP a) Source # | |
| Show a => Show (NumBP a) Source # | |
| Generic (NumBP a) Source # | |
| NFData a => NFData (NumBP a) Source # | |
| Num a => Backprop (NumBP a) Source # | |
| type Rep (NumBP a) Source # | |
Explicit zero, add, and one
"Zero out" all components of a value. For scalar values, this should
just be . For vectors and matrices, this should set all
components to zero, the additive identity.const 0
Should be idempotent: Applying the function twice is the same as applying it just once.
Each type should ideally only have one ZeroFunc. This coherence
constraint is given by the typeclass Backprop.
Since: 0.2.0.0
Add together two values of a type. To combine contributions of gradients, so should ideally be information-preserving.
See laws for Backprop for the laws this should be expected to
preserve. Namely, it should be commutative and associative, with an
identity for a valid ZeroFunc.
Each type should ideally only have one AddFunc. This coherence
constraint is given by the typeclass Backprop.
Since: 0.2.0.0
One all components of a value. For scalar values, this should
just be . For vectors and matrices, this should set all
components to one, the multiplicative identity.const 1
Should be idempotent: Applying the function twice is the same as applying it just once.
Each type should ideally only have one OneFunc. This coherence
constraint is given by the typeclass Backprop.
Since: 0.2.0.0
Running
backprop :: ZeroFunc a -> OneFunc b -> (forall s. Reifies s W => BVar s a -> BVar s b) -> a -> (b, a) Source #
gradBP :: ZeroFunc a -> OneFunc b -> (forall s. Reifies s W => BVar s a -> BVar s b) -> a -> a Source #
backpropWith :: ZeroFunc a -> (forall s. Reifies s W => BVar s a -> BVar s b) -> a -> (b, b -> a) Source #
backpropWith, but with explicit zero.
Note that argument order changed in v0.2.4.
Multiple inputs
backprop2 :: ZeroFunc a -> ZeroFunc b -> OneFunc c -> (forall s. Reifies s W => BVar s a -> BVar s b -> BVar s c) -> a -> b -> (c, (a, b)) Source #
gradBP2 :: ZeroFunc a -> ZeroFunc b -> OneFunc c -> (forall s. Reifies s W => BVar s a -> BVar s b -> BVar s c) -> a -> b -> (a, b) Source #
backpropWith2 :: ZeroFunc a -> ZeroFunc b -> (forall s. Reifies s W => BVar s a -> BVar s b -> BVar s c) -> a -> b -> (c, c -> (a, b)) Source #
backpropN :: forall as b. Prod ZeroFunc as -> OneFunc b -> (forall s. Reifies s W => Prod (BVar s) as -> BVar s b) -> Tuple as -> (b, Tuple as) Source #
evalBPN :: forall as b. (forall s. Reifies s W => Prod (BVar s) as -> BVar s b) -> Tuple as -> b Source #
evalBP generalized to multiple inputs of different types. See
documentation for backpropN for more details.
gradBPN :: Prod ZeroFunc as -> OneFunc b -> (forall s. Reifies s W => Prod (BVar s) as -> BVar s b) -> Tuple as -> Tuple as Source #
backpropWithN :: forall as b. Prod ZeroFunc as -> (forall s. Reifies s W => Prod (BVar s) as -> BVar s b) -> Tuple as -> (b, b -> Tuple as) Source #
backpropWithN, but with explicit zero and one.
Note that argument order changed in v0.2.4.
Since: 0.2.0.0
class EveryC k c as => Every k (c :: k -> Constraint) (as :: [k]) #
Minimal complete definition
Manipulating BVar
constVar :: a -> BVar s a Source #
Lift a value into a BVar representing a constant value.
This value will not be considered an input, and its gradients will not be backpropagated.
coerceVar :: Coercible a b => BVar s a -> BVar s b Source #
Coerce a BVar contents. Useful for things like newtype wrappers.
Since: 0.1.5.2
viewVar :: forall a b s. Reifies s W => AddFunc a -> ZeroFunc b -> Lens' b a -> BVar s b -> BVar s a Source #
setVar :: forall a b s. Reifies s W => AddFunc a -> AddFunc b -> ZeroFunc a -> Lens' b a -> BVar s a -> BVar s b -> BVar s b Source #
overVar :: Reifies s W => AddFunc a -> AddFunc b -> ZeroFunc a -> ZeroFunc b -> Lens' b a -> (BVar s a -> BVar s a) -> BVar s b -> BVar s b Source #
sequenceVar :: forall t a s. (Reifies s W, Traversable t) => AddFunc a -> ZeroFunc a -> BVar s (t a) -> t (BVar s a) Source #
sequenceVar, but with explicit add and zero.
collectVar :: forall t a s. (Reifies s W, Foldable t, Functor t) => AddFunc a -> ZeroFunc a -> t (BVar s a) -> BVar s (t a) Source #
collectVar, but with explicit add and zero.
previewVar :: forall b a s. Reifies s W => AddFunc a -> ZeroFunc b -> Traversal' b a -> BVar s b -> Maybe (BVar s a) Source #
previewVar, but with explicit add and zero.
toListOfVar :: forall b a s. Reifies s W => AddFunc a -> ZeroFunc b -> Traversal' b a -> BVar s b -> [BVar s a] Source #
toListOfVar, but with explicit add and zero.
With Isomorphisms
isoVar2 :: Reifies s W => AddFunc a -> AddFunc b -> (a -> b -> c) -> (c -> (a, b)) -> BVar s a -> BVar s b -> BVar s c Source #
isoVar3 :: Reifies s W => AddFunc a -> AddFunc b -> AddFunc c -> (a -> b -> c -> d) -> (d -> (a, b, c)) -> BVar s a -> BVar s b -> BVar s c -> BVar s d Source #
isoVarN :: Reifies s W => Prod AddFunc as -> (Tuple as -> b) -> (b -> Tuple as) -> Prod (BVar s) as -> BVar s b Source #
With Ops
liftOp :: forall as b s. Reifies s W => Prod AddFunc as -> Op as b -> Prod (BVar s) as -> BVar s b Source #
liftOp2 :: forall a b c s. Reifies s W => AddFunc a -> AddFunc b -> Op '[a, b] c -> BVar s a -> BVar s b -> BVar s c Source #
liftOp3 :: forall a b c d s. Reifies s W => AddFunc a -> AddFunc b -> AddFunc c -> Op '[a, b, c] d -> BVar s a -> BVar s b -> BVar s c -> BVar s d Source #
Generics
class BVGroup s as i o | o -> i, i -> as Source #
Helper class for generically "splitting" and "joining" BVars into
constructors. See splitBV and
joinBV.
See Numeric.Backprop for a tutorial on how to use this.
Instances should be available for types made with one constructor whose
fields are all instances of Backprop, with a Generic instance.
Since: 0.2.2.0
Minimal complete definition
gsplitBV, gjoinBV
Instances
| BVGroup s as i o => BVGroup s as (M1 * p c i) (M1 * p c o) Source # | |
| BVGroup s ([] *) (U1 *) (U1 *) Source # | |
| BVGroup s ([] *) (V1 *) (V1 *) Source # | |
| BVGroup s ([] *) (K1 * i a) (K1 * i (BVar s a)) Source # | |
| (Reifies Type s W, BVGroup s as i1 o1, BVGroup s bs i2 o2, (~) [*] cs ((++) * as bs), Known [*] (Length *) as) => BVGroup s ((:) * (i1 ()) ((:) * (i2 ()) cs)) ((:+:) * i1 i2) ((:+:) * o1 o2) Source # | This instance is possible but it is not clear when it would be useful |
| (Reifies Type s W, BVGroup s as i1 o1, BVGroup s bs i2 o2, (~) [*] cs ((++) * as bs), Known [*] (Length *) as) => BVGroup s ((:) * (i1 ()) ((:) * (i2 ()) cs)) ((:*:) * i1 i2) ((:*:) * o1 o2) Source # | |
Op
An describes a differentiable function from Op as aas to a.
For example, a value of type
Op '[Int, Bool] Double
is a function from an Int and a Bool, returning a Double. It can
be differentiated to give a gradient of an Int and a Bool if given
a total derivative for the Double. If we call Bool \(2\), then,
mathematically, it is akin to a:
\[ f : \mathbb{Z} \times 2 \rightarrow \mathbb{R} \]
See runOp, gradOp, and gradOpWith for examples on how to run it,
and Op for instructions on creating it.
It is simpler to not use this type constructor directly, and instead use
the op2, op1, op2, and op3 helper smart constructors.
See Numeric.Backprop.Op for a mini-tutorial on using Prod and
Tuple.
To use an Op with the backprop library, see liftOp, liftOp1,
liftOp2, and liftOp3.
Constructors
| Op | Construct an See the module documentation for Numeric.Backprop.Op for more
details on the function that this constructor and |
Fields
| |
Instances
| (Known [*] (Length *) as, Every * Floating as, Every * Fractional as, Every * Num as, Floating a) => Floating (Op as a) Source # | |
| (Known [*] (Length *) as, Every * Fractional as, Every * Num as, Fractional a) => Fractional (Op as a) Source # | |
| (Known [*] (Length *) as, Every * Num as, Num a) => Num (Op as a) Source # | |
Creation
opConst :: (Every Num as, Known Length as) => a -> Op as a Source #
An Op that ignores all of its inputs and returns a given constant
value.
>>>gradOp' (opConst 10) (1 ::< 2 ::< 3 ::< Ø)(10, 0 ::< 0 ::< 0 ::< Ø)
opConst' :: Every Num as => Length as -> a -> Op as a Source #
A version of opConst taking explicit Length, indicating the
number of inputs and their types.
Requiring an explicit Length is mostly useful for rare "extremely
polymorphic" situations, where GHC can't infer the type and length of
the the expected input tuple. If you ever actually explicitly write
down as as a list of types, you should be able to just use
opConst.
Giving gradients directly
op1 :: (a -> (b, b -> a)) -> Op '[a] b Source #
Create an Op of a function taking one input, by giving its explicit
derivative. The function should return a tuple containing the result of
the function, and also a function taking the derivative of the result
and return the derivative of the input.
If we have
\[ \eqalign{ f &: \mathbb{R} \rightarrow \mathbb{R}\cr y &= f(x)\cr z &= g(y) } \]
Then the derivative \( \frac{dz}{dx} \), it would be:
\[ \frac{dz}{dx} = \frac{dz}{dy} \frac{dy}{dx} \]
If our Op represents \(f\), then the second item in the resulting
tuple should be a function that takes \(\frac{dz}{dy}\) and returns
\(\frac{dz}{dx}\).
As an example, here is an Op that squares its input:
square :: Num a =>Op'[a] a square =op1$ \x -> (x*x, \d -> 2 * d * x )
Remember that, generally, end users shouldn't directly construct Ops;
they should be provided by libraries or generated automatically.
op2 :: (a -> b -> (c, c -> (a, b))) -> Op '[a, b] c Source #
Create an Op of a function taking two inputs, by giving its explicit
gradient. The function should return a tuple containing the result of
the function, and also a function taking the derivative of the result
and return the derivative of the input.
If we have
\[ \eqalign{ f &: \mathbb{R}^2 \rightarrow \mathbb{R}\cr z &= f(x, y)\cr k &= g(z) } \]
Then the gradient \( \left< \frac{\partial k}{\partial x}, \frac{\partial k}{\partial y} \right> \) would be:
\[ \left< \frac{\partial k}{\partial x}, \frac{\partial k}{\partial y} \right> = \left< \frac{dk}{dz} \frac{\partial z}{dx}, \frac{dk}{dz} \frac{\partial z}{dy} \right> \]
If our Op represents \(f\), then the second item in the resulting
tuple should be a function that takes \(\frac{dk}{dz}\) and returns
\( \left< \frac{\partial k}{dx}, \frac{\partial k}{dx} \right> \).
As an example, here is an Op that multiplies its inputs:
mul :: Num a =>Op'[a, a] a mul =op2'$ \x y -> (x*y, \d -> (d*y, x*d) )
Remember that, generally, end users shouldn't directly construct Ops;
they should be provided by libraries or generated automatically.
From Isomorphisms
opTup :: Op as (Tuple as) Source #
An Op that takes as and returns exactly the input tuple.
>>>gradOp' opTup (1 ::< 2 ::< 3 ::< Ø)(1 ::< 2 ::< 3 ::< Ø, 1 ::< 1 ::< 1 ::< Ø)
opIsoN :: (Tuple as -> b) -> (b -> Tuple as) -> Op as b Source #
An Op that runs the input value through an isomorphism between
a tuple of values and a value. See opIso for caveats.
In Numeric.Backprop.Op since version 0.1.2.0, but only exported from Numeric.Backprop since version 0.1.3.0.
Since: 0.1.2.0
No gradients
noGrad1 :: (a -> b) -> Op '[a] b Source #
Create an Op with no gradient. Can be evaluated with evalOp, but
will throw a runtime exception when asked for the gradient.
Can be used with BVar with liftOp1, and evalBP will work fine.
gradBP and backprop will also work fine if the result is never used
in the final answer, but will throw a runtime exception if the final
answer depends on the result of this operation.
Useful if your only API is exposed through backprop. Just be sure to tell your users that this will explode when finding the gradient if the result is used in the final result.
Since: 0.1.3.0
noGrad :: (Tuple as -> b) -> Op as b Source #
Create an Op with no gradient. Can be evaluated with evalOp, but
will throw a runtime exception when asked for the gradient.
Can be used with BVar with liftOp, and evalBP will work fine.
gradBP and backprop will also work fine if the result is never used
in the final answer, but will throw a runtime exception if the final
answer depends on the result of this operation.
Useful if your only API is exposed through backprop. Just be sure to tell your users that this will explode when finding the gradient if the result is used in the final result.
Since: 0.1.3.0
Utility
Inductive tuples/heterogeneous lists
data Prod k (f :: k -> *) (a :: [k]) :: forall k. (k -> *) -> [k] -> * where #
Instances
| Witness ØC ØC (Prod k f (Ø k)) | |
| Functor1 k [k] (Prod k) | |
| Foldable1 k [k] (Prod k) | |
| Traversable1 k [k] (Prod k) | |
| IxFunctor1 k [k] (Index k) (Prod k) | |
| IxFoldable1 k [k] (Index k) (Prod k) | |
| IxTraversable1 k [k] (Index k) (Prod k) | |
| TestEquality k f => TestEquality [k] (Prod k f) | |
| BoolEquality k f => BoolEquality [k] (Prod k f) | |
| Eq1 k f => Eq1 [k] (Prod k f) | |
| Ord1 k f => Ord1 [k] (Prod k f) | |
| Show1 k f => Show1 [k] (Prod k f) | |
| Read1 k f => Read1 [k] (Prod k f) | |
| (Known [k] (Length k) as, Every k (Known k f) as) => Known [k] (Prod k f) as | |
| (Witness p q (f a2), Witness s t (Prod a1 f as)) => Witness (p, s) (q, t) (Prod a1 f ((:<) a1 a2 as)) | |
| ListC ((<$>) * Constraint Eq ((<$>) k * f as)) => Eq (Prod k f as) | |
| (ListC ((<$>) * Constraint Eq ((<$>) k * f as)), ListC ((<$>) * Constraint Ord ((<$>) k * f as))) => Ord (Prod k f as) | |
| ListC ((<$>) * Constraint Show ((<$>) k * f as)) => Show (Prod k f as) | |
| ListC ((<$>) * Constraint Backprop ((<$>) * * f as)) => Backprop (Prod * f as) Source # | |
| type WitnessC ØC ØC (Prod k f (Ø k)) | |
| type KnownC [k] (Prod k f) as | |
| type WitnessC (p, s) (q, t) (Prod a1 f ((:<) a1 a2 as)) | |
pattern (:>) :: forall k (f :: k -> *) (a :: k) (b :: k). f a -> f b -> Prod k f ((:) k a ((:) k b ([] k))) infix 6 #
Construct a two element Prod. Since the precedence of (:>) is higher than (:<), we can conveniently write lists like:
>>>a :< b :> c
Which is identical to:
>>>a :< b :< c :< Ø
pattern (::<) :: forall a (as :: [*]). a -> Tuple as -> Tuple ((:<) * a as) infixr 5 #
Cons onto a Tuple.
Misc
class Reifies k (s :: k) a | s -> a #
Minimal complete definition
Instances
| KnownNat n => Reifies Nat n Integer | |
| KnownSymbol n => Reifies Symbol n String | |
| Reifies * Z Int | |
| Reifies * n Int => Reifies * (D n) Int | |
| Reifies * n Int => Reifies * (SD n) Int | |
| Reifies * n Int => Reifies * (PD n) Int | |
| (B * b0, B * b1, B * b2, B * b3, B * b4, B * b5, B * b6, B * b7, (~) * w0 (W b0 b1 b2 b3), (~) * w1 (W b4 b5 b6 b7)) => Reifies * (Stable w0 w1 a) a | |