Simplify - with at-j (#9)

* Simplify - with at-j

* Fix format

Author: blegat

src/reverse_mode.jl

@@ -147,11 +147,11 @@ function _forward_eval(
                 @inbounds ix1 = children_arr[child1]
                 @inbounds ix2 = children_arr[child1+1]
                 for j in _eachindex(f.sizes, k)
-                    tmp_sub = _getindex(f.forward_storage, f.sizes, ix1, j)
-                    tmp_sub -= _getindex(f.forward_storage, f.sizes, ix2, j)
-                    _setindex!(f.partials_storage, one(T), f.sizes, ix1, j)
-                    _setindex!(f.partials_storage, -one(T), f.sizes, ix2, j)
-                    _setindex!(f.forward_storage, tmp_sub, f.sizes, k, j)
+                    tmp_sub = @j f.forward_storage[ix1]
+                    tmp_sub -= @j f.forward_storage[ix2]
+                    @j f.partials_storage[ix1] = one(T)
+                    @j f.partials_storage[ix2] = -one(T)
+                    @j f.forward_storage[k] = tmp_sub
                 end
             elseif node.index == 3 # :*
                 tmp_prod = one(T)

src/sizes.jl

@@ -61,10 +61,25 @@ macro j(expr)
         lhs, rhs = expr.args
         @assert Meta.isexpr(lhs, :ref)
         @assert length(expr.args) == 2
-        return Expr(:call, :_setindex!, esc(lhs.args[1]), esc(rhs), esc(:(f.sizes)), esc(lhs.args[2]), esc(:j))
+        return Expr(
+            :call,
+            :_setindex!,
+            esc(lhs.args[1]),
+            esc(rhs),
+            esc(:(f.sizes)),
+            esc(lhs.args[2]),
+            esc(:j),
+        )
     elseif Meta.isexpr(expr, :ref) && length(expr.args) == 2
         arr, idx = expr.args
-        return Expr(:call, :_getindex, esc(arr), esc(:(f.sizes)), esc(idx), esc(:j))
+        return Expr(
+            :call,
+            :_getindex,
+            esc(arr),
+            esc(:(f.sizes)),
+            esc(idx),
+            esc(:j),
+        )
     else
         error("Unsupported expression `$expr`")
     end