emmy.autodiff — org.mentat/emmy 0.32.0

deep-primal clj/s

(deep-primal v)

Version of [[tape-primal]] that will descend recursively into any perturbation instance returned by [[tape-primal]] or emmy.dual/primal until encountering a non-perturbation.

Given a non-perturbation, acts as identity.

inner-tag clj/s

(inner-tag & tags)

Given any number of tags, returns the tag most recently bound via [[with-active-tag]] (i.e., the tag connected with the innermost call to [[with-active-tag]]).

If none of the tags are bound, returns (apply max tags).

lift-1 clj/s

(lift-1 f)

(lift-1 f df:dx)

Given:

• some unary function f
• a function df:dx that computes the derivative of f with respect to its single argument

Returns a new unary function that operates on both the original type of f, [[TapeCell]] and [[emmy.dual/Dual]] instances.

If called without df:dx, df:dx defaults to (f :dfdx); this will return the derivative registered to a generic function defined with emmy.util.def/defgeneric.

NOTE: df:dx has to ALREADY be able to handle [[TapeCell]] and [[emmy.dual/Dual]] instances. The best way to accomplish this is by building df:dx out of already-lifted functions, and declaring them by forward reference if you need to.

lift-2 clj/s

(lift-2 f)

(lift-2 f df:dx df:dy)

Given:

• some binary function f
• a function df:dx that computes the derivative of f with respect to its single argument
• a function df:dy, similar to df:dx for the second arg

Returns a new binary function that operates on both the original type of f, [[TapeCell]] and [[emmy.dual/Dual]] instances.

NOTE: df:dx and df:dy have to ALREADY be able to handle [[TapeCell]] and [[emmy.dual/Dual]] instances. The best way to accomplish this is by building df:dx and df:dy out of already-lifted functions, and declaring them by forward reference if you need to.

lift-n clj/s

(lift-n f df:dx df:dx1 df:dx2)

Given:

• some function f that can handle 0, 1 or 2 arguments
• df:dx, a fn that returns the derivative wrt the single arg in the unary case
• df:dx1 and df:dx2, fns that return the derivative with respect to the first and second args in the binary case

Returns a new any-arity function that operates on both the original type of f, [[TapeCell]] and [[emmy.dual/Dual]] instances.

NOTE: The n-ary case of f is populated by nested calls to the binary case. That means that this is NOT an appropriate lifting method for an n-ary function that isn't built out of associative binary calls. If you need this ability, please file an issue at the emmy issue tracker.

primal-of clj/s

(primal-of v)

(primal-of v tag)

More permissive version of emmy.tape/tape-primal that returns v when passed a non-perturbation.

tag+perturbation clj/s

(tag+perturbation & dxs)

Given any number of dxs, returns a pair of the form

[<tag> <tape-or-dual-number>]

containing the tag and instance of [[emmy.dual/Dual]] or [[TapeCell]] associated with the inner-most call to [[with-active-tag]] in the current call stack.

If none of dxs has an active tag, returns nil.

tag-of clj/s

(tag-of x)

More permissive version of emmy.tape/tape-tag that returns nil when passed a non-perturbation.