Update docs to be compatible with ChainRules and document about using…

… ChainRulesCore

.github/workflows/CI.yml

@@ -81,7 +81,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: julia-actions/setup-julia@v1
         with:
-          version: '1'
+          version: '1.6'
       - run: |
           julia --project=docs -e '
             using Pkg

.gitignore

@@ -1,7 +1,11 @@
+*.pdf
+*.DS_Store
 *.jl.cov
 *.jl.*.cov
 *.jl.mem
-*.pdf
-*.DS_Store
 Manifest.toml
-docs/build/
+docs/build
+docs/site
+docs/src/assets/chainrules.css
+docs/src/assets/indigo.css
+.vscode/settings.json

docs/Project.toml

@@ -1,5 +1,7 @@
 [deps]
+DocThemeIndigo = "8bac0ac5-51bf-41f9-885e-2bf1ac2bec5f"
 Documenter = "e30172f5-a6a5-5a46-863b-614d45cd2de4"
+Nabla = "49c96f43-aa6d-5a04-a506-44c7070ebe78"
 
 [compat]
-Documenter = "~0.19"
+Documenter = "0.27"

docs/make.jl

@@ -1,25 +1,26 @@
-using Documenter, Nabla
+using Documenter
+using DocThemeIndigo
+using Nabla
 
+const indigo = DocThemeIndigo.install(Nabla)
 makedocs(
     modules=[Nabla],
-    format=:html,
+    format=Documenter.HTML(
+        prettyurls=false,
+        assets=[indigo],
+    ),
+    sitename="Nabla.jl",
+    authors="Invenia Labs",
     pages=[
         "Home" => "index.md",
         "API" => "pages/api.md",
         "Custom Sensitivities" => "pages/custom.md",
         "Details" => "pages/autodiff.md",
     ],
-    sitename="Nabla.jl",
-    authors="Invenia Labs",
-    assets=[
-        "assets/invenia.css",
-    ],
 )
 
+
 deploydocs(
     repo = "github.com/invenia/Nabla.jl.git",
-    julia = "1.0",
-    target = "build",
-    deps = nothing,
-    make = nothing,
-)
+    push_preview=true,
+)

docs/src/pages/custom.md

@@ -1,4 +1,19 @@
-# Custom Sensitivities
+# Custom Sensitivities 
+
+!!! note "Prefer to use ChainRulesCore to define custom sensitivities"
+    Nabla supports the use of [ChainRulesCore](http://www.juliadiff.org/ChainRulesCore.jl/stable/) to define custom sensitivities.
+    It is preferred to define the custom sensitivities using `ChainRulesCore.rrule` as they will work for many AD systems, not just Nabla.
+    **It is also much easier, than the Nabla specific way**.
+    These sensitivities can be added in your own package, or for Base/StdLib functions they can be added to [ChainRules.jl](https://github.com/JuliaDiff/ChainRules.jl/).
+    To define custom sensitivities using ChainRulesCore, define a `ChainRulesCore.rrule(f, args...; kwargs...)`.
+    See the [ChainRules project's documentation for more information](https://www.juliadiff.org/ChainRulesCore.jl/stable/).
+    **If you are defining your custom sensitivities using ChainRulesCore then you do not need to read this page**, and can consider it as documenting a legacy feature.
+
+    This page exists to describe how Nabla works, and how sensitivities can be directly defined for Nabla.
+    Defining sensitivities this way does not make them accessible to other AD systems, but does let you do things that directly depend on how Nabla works.
+    It allows for specific definitions of sensitivities that are only defined for Nabla (which might work differently to more generic definitions defined for all AD).
+
+# Legacy Method
 
 Part of the power of Nabla is its extensibility, specifically in the form of defining
 custom sensitivities for functions.