Portability GHC only experimental ekmett@gmail.com

Description

Mixed-Mode Automatic Differentiation.

Each combinator exported from this module chooses an appropriate AD mode.

Synopsis

grad :: (Traversable f, Num a) => (forall s. Mode s => f (AD s a) -> AD s a) -> f a -> f aSource

The grad function calculates the gradient of a non-scalar-to-scalar function with Reverse AD in a single pass.

grad' :: (Traversable f, Num a) => (forall s. Mode s => f (AD s a) -> AD s a) -> f a -> (a, f a)Source

The grad' function calculates the result and gradient of a non-scalar-to-scalar function with Reverse AD in a single pass.

gradWith :: (Traversable f, Num a) => (a -> a -> b) -> (forall s. Mode s => f (AD s a) -> AD s a) -> f a -> f bSource

grad g f function calculates the gradient of a non-scalar-to-scalar function f with reverse-mode AD in a single pass. The gradient is combined element-wise with the argument using the function g.

gradWith' :: (Traversable f, Num a) => (a -> a -> b) -> (forall s. Mode s => f (AD s a) -> AD s a) -> f a -> (a, f b)Source

grad' g f calculates the result and gradient of a non-scalar-to-scalar function f with Reverse AD in a single pass the gradient is combined element-wise with the argument using the function g.

# Jacobians

jacobian :: (Traversable f, Traversable g, Num a) => (forall s. Mode s => f (AD s a) -> g (AD s a)) -> f a -> g (f a)Source

Calculate the Jacobian of a non-scalar-to-non-scalar function, automatically choosing between forward and reverse mode AD based on the number of inputs and outputs.

jacobian' :: (Traversable f, Traversable g, Num a) => (forall s. Mode s => f (AD s a) -> g (AD s a)) -> f a -> g (a, f a)Source

Calculate both the answer and Jacobian of a non-scalar-to-non-scalar function, automatically choosing between forward- and reverse- mode AD based on the relative, number of inputs and outputs.

jacobianWith :: (Traversable f, Traversable g, Num a) => (a -> a -> b) -> (forall s. Mode s => f (AD s a) -> g (AD s a)) -> f a -> g (f b)Source

jacobianWith g f calculates the Jacobian of a non-scalar-to-non-scalar function, automatically choosing between forward and reverse mode AD based on the number of inputs and outputs.

The resulting Jacobian matrix is then recombined element-wise with the input using g.

jacobianWith' :: (Traversable f, Traversable g, Num a) => (a -> a -> b) -> (forall s. Mode s => f (AD s a) -> g (AD s a)) -> f a -> g (a, f b)Source

jacobianWith' g f calculates the answer and Jacobian of a non-scalar-to-non-scalar function, automatically choosing between forward and reverse mode AD based on the number of inputs and outputs.

The resulting Jacobian matrix is then recombined element-wise with the input using g.

# Derivatives (Forward)

diff :: Num a => (forall s. Mode s => AD s a -> AD s a) -> a -> aSource

The diff function calculates the first derivative of a scalar-to-scalar function by forward-mode AD

diff sin == cos

diffF :: (Functor f, Num a) => (forall s. Mode s => AD s a -> f (AD s a)) -> a -> f aSource

The diffF function calculates the first derivative of scalar-to-nonscalar function by Forward AD

diff' :: Num a => (forall s. Mode s => AD s a -> AD s a) -> a -> (a, a)Source

The d'UU function calculates the result and first derivative of scalar-to-scalar function by Forward AD

d' sin == sin &&& cos
d' f = f &&& d f

diffF' :: (Functor f, Num a) => (forall s. Mode s => AD s a -> f (AD s a)) -> a -> f (a, a)Source

The diffF' function calculates the result and first derivative of a scalar-to-non-scalar function by Forward AD

# Derivatives (Tower)

diffs :: Num a => (forall s. Mode s => AD s a -> AD s a) -> a -> [a]Source

diffsF :: (Functor f, Num a) => (forall s. Mode s => AD s a -> f (AD s a)) -> a -> f [a]Source

diffs0 :: Num a => (forall s. Mode s => AD s a -> AD s a) -> a -> [a]Source

diffs0F :: (Functor f, Num a) => (forall s. Mode s => AD s a -> f (AD s a)) -> a -> f [a]Source

# Directional Derivatives (Forward)

du :: (Functor f, Num a) => (forall s. Mode s => f (AD s a) -> AD s a) -> f (a, a) -> aSource

du' :: (Functor f, Num a) => (forall s. Mode s => f (AD s a) -> AD s a) -> f (a, a) -> (a, a)Source

duF :: (Functor f, Functor g, Num a) => (forall s. Mode s => f (AD s a) -> g (AD s a)) -> f (a, a) -> g aSource

duF' :: (Functor f, Functor g, Num a) => (forall s. Mode s => f (AD s a) -> g (AD s a)) -> f (a, a) -> g (a, a)Source

# Taylor Series (Tower)

taylor :: Fractional a => (forall s. Mode s => AD s a -> AD s a) -> a -> a -> [a]Source

taylor0 :: Fractional a => (forall s. Mode s => AD s a -> AD s a) -> a -> a -> [a]Source

maclaurin :: Fractional a => (forall s. Mode s => AD s a -> AD s a) -> a -> [a]Source

maclaurin0 :: Fractional a => (forall s. Mode s => AD s a -> AD s a) -> a -> [a]Source

diffM :: (Monad m, Num a) => (forall s. Mode s => AD s a -> m (AD s a)) -> a -> m aSource

The dUM function calculates the first derivative of scalar-to-scalar monadic function by Forward AD

diffM' :: (Monad m, Num a) => (forall s. Mode s => AD s a -> m (AD s a)) -> a -> m (a, a)Source

The d'UM function calculates the result and first derivative of a scalar-to-scalar monadic function by Forward AD

gradM :: (Traversable f, Monad m, Num a) => (forall s. Mode s => f (AD s a) -> m (AD s a)) -> f a -> m (f a)Source

gradM' :: (Traversable f, Monad m, Num a) => (forall s. Mode s => f (AD s a) -> m (AD s a)) -> f a -> m (a, f a)Source

gradWithM :: (Traversable f, Monad m, Num a) => (a -> a -> b) -> (forall s. Mode s => f (AD s a) -> m (AD s a)) -> f a -> m (f b)Source

gradWithM' :: (Traversable f, Monad m, Num a) => (a -> a -> b) -> (forall s. Mode s => f (AD s a) -> m (AD s a)) -> f a -> m (a, f b)Source

# Exposed Types

AD serves as a common wrapper for different Mode instances, exposing a traditional numerical tower. Universal quantification is used to limit the actions in user code to machinery that will return the same answers under all AD modes, allowing us to use modes interchangeably as both the type level "brand" and dictionary, providing a common API.

Constructors

Instances

class Lifted t => Mode t whereSource

Methods

lift :: Num a => a -> t aSource

Embed a constant

(<+>) :: Num a => t a -> t a -> t aSource

Vector sum

(*^) :: Num a => a -> t a -> t aSource

Scalar-vector multiplication

(^*) :: Num a => t a -> a -> t aSource

Vector-scalar multiplication

(^/) :: Fractional a => t a -> a -> t aSource

Scalar division

zero :: Num a => t aSource

'zero' = 'lift' 0

Instances

 Mode Id Lifted Forward => Mode Forward Lifted Reverse => Mode Reverse Lifted Tower => Mode Tower Mode f => Mode (AD f)