Support all output types in reverse-mode

.dir-locals.el

@@ -5,5 +5,10 @@
      (cider-clojure-cli-aliases . ":test:cljs:nextjournal/clerk:dev")
 
      ;; Custom indentation:
-     (eval . (put-clojure-indent 'sci-macro :defn))
-     (eval . (put-clojure-indent 'careful-def 1)))))
+     (eval . (progn
+               ;; the require here avoids projectile errors:
+               ;;   "Symbol’s function definition is void: put-clojure-indent"
+               (require 'clojure-mode)
+               (require 'cider)
+               (put-clojure-indent 'sci-macro :defn)
+               (put-clojure-indent 'careful-def 1))))))

CHANGELOG.md

@@ -2,6 +2,16 @@
 
 ## [unreleased]
 
+- PR:
+
+  - all lifted function machinery and impls moves to `emmy.autodiff`
+  - `emmy.differential` moves to `emmy.dual`
+  - deletes perturbed?
+  - iperturbed impl for functions moves to `emmy.function`
+  - adds extract-id, makes reverse-mode work with lots of output types
+  - new `mode` arg for `extract-tangent`
+  - single `derivative` moves to `emmy.dual`
+
 - #156:
 
   - Makes forward- and reverse-mode automatic differentiation compatible with

src/emmy/abstract/function.cljc

@@ -12,7 +12,8 @@
   (:refer-clojure :exclude [name])
   (:require #?(:clj [clojure.pprint :as pprint])
             [emmy.abstract.number :as an]
-            [emmy.differential :as d]
+            [emmy.autodiff :as ad]
+            [emmy.dual :as dual]
             [emmy.function :as f]
             [emmy.generic :as g]
             [emmy.matrix :as m]
@@ -260,17 +261,15 @@
     - the `tag` of the innermost active derivative call
 
   And returns a folding function (designed for use
-  with [[emmy.structure/fold-chain]]) that
-
-  generates a new [[emmy.differential/Dual]] by applying the chain rule and
-  summing the partial derivatives for each perturbed argument in the input
-  structure."
+  with [[emmy.structure/fold-chain]]) that generates a new [[emmy.dual/Dual]] by
+  applying the chain rule and summing the partial derivatives for each perturbed
+  argument in the input structure."
   [f primal-s tag]
   (fn
     ([] 0)
-    ([tangent] (d/bundle-element (apply f primal-s) tangent tag))
+    ([tangent] (dual/bundle-element (apply f primal-s) tangent tag))
     ([tangent [x path _]]
-     (let [dx (d/tangent x tag)]
+     (let [dx (dual/tangent x tag)]
        (if (g/numeric-zero? dx)
          tangent
          (let [partial (literal-partial f path)]
@@ -309,7 +308,7 @@
 
   and generates the proper return value for `((D f) xs)`.
 
-  In forward-mode AD this is a new [[emmy.differential/Dual]] generated by
+  In forward-mode AD this is a new [[emmy.dual/Dual]] generated by
   applying the chain rule and summing the partial derivatives for each perturbed
   argument in the input structure.
 
@@ -318,9 +317,9 @@
   that input."
   [f s tag dx]
   (let [fold-fn  (cond (tape/tape? dx) reverse-mode-fold
-                       (d/dual? dx)    forward-mode-fold
+                       (dual/dual? dx) forward-mode-fold
                        :else           (u/illegal "No tape or differential inputs."))
-        primal-s (s/mapr (fn [x] (tape/primal-of x tag)) s)]
+        primal-s (s/mapr (fn [x] (ad/primal-of x tag)) s)]
     (s/fold-chain (fold-fn f primal-s tag) s)))
 
 (defn- check-argument-type
@@ -355,7 +354,7 @@
     (if-let [[tag dx] (s/fold-chain
                        (fn
                          ([] [])
-                         ([acc]     (apply tape/tag+perturbation acc))
+                         ([acc]     (apply ad/tag+perturbation acc))
                          ([acc [d]] (conj acc d)))
                        s)]
       (literal-derivative f s tag dx)

src/emmy/abstract/number.cljc

@@ -219,12 +219,12 @@
   (memoize g/simplify))
 
 (defn ^:no-doc simplify-numerical-expression
-  "This function will only simplify instances of [[expression/Literal]]; if `x` is
-  of that type, [[simplify-numerical-expression]] acts as a memoized version
-  of [[generic/simplify]]. Else, acts as identity.
+  "This function will only simplify instances of [[emmy.expression/Literal]]; if
+  `x` is of that type, [[simplify-numerical-expression]] acts as a memoized
+  version of [[generic/simplify]]. Else, acts as identity.
 
-  This trick is used in [[emmy.calculus.manifold]] to memoize
-  simplification _only_ for non-[[differential/Differential]] types."
+  This trick is used in [[emmy.calculus.manifold]] to memoize simplification
+  _only_ for non-perturbed types."
   [x]
   (if (literal-number? x)
     (memoized-simplify x)