From 438a362b5ac786aac70d18adea0c5c23a80981a7 Mon Sep 17 00:00:00 2001
From: Tao Wang <fsxbhyy@gmail.com>
Date: Sat, 30 Sep 2023 01:14:55 -0400
Subject: [PATCH] minor change

---
 src/computational_graph/operation.jl | 33 ++++++++++++++++++++++++----
 1 file changed, 29 insertions(+), 4 deletions(-)

diff --git a/src/computational_graph/operation.jl b/src/computational_graph/operation.jl
index 307cc93e..bd6de437 100644
--- a/src/computational_graph/operation.jl
+++ b/src/computational_graph/operation.jl
@@ -47,8 +47,8 @@ end
     
     Given a  graph G and an id of graph g, calculate the derivative d G / d g by forward propagation algorithm.
 # Arguments:
-- `diag::Graph{F,W}`:  Graph to be differentiated
-- `ID::Int`: ID of the graph that is  
+- `diag::Graph{F,W}`:  Graph G to be differentiated
+- `ID::Int`: ID of the graph g  
 """
 function forwardAD(diag::Graph{F,W}, ID::Int) where {F,W}
     # use a dictionary to host the dual diagram of a diagram for a given hash number
@@ -111,6 +111,14 @@ function forwardAD(diag::Graph{F,W}, ID::Int) where {F,W}
     return dual[rootid]
 end
 
+"""
+    function all_parent(diag::Graph{F,W}) where {F,W}
+    
+    Given a  graph, find all parents node of each node, and return them in a dictionary.
+# Arguments:
+- `diag::Graph{F,W}`:  Target graph
+"""
+
 function all_parent(diag::Graph{F,W}) where {F,W}
     result = Dict{Int,Vector{Graph{F,W}}}()
     for d in PostOrderDFS(diag)
@@ -129,13 +137,22 @@ function all_parent(diag::Graph{F,W}) where {F,W}
     return result
 end
 
+"""
+function node_derivative(g1::Graph{F,W}, g2::Graph{F,W}) where {F,W} 
+    
+    Return the local derivative d g1/ dg2 at node g1. The local derivative only considers the subgraph of node g1, and ignores g2 that appears in deeper layers.
+    Example: For g1 = G *g2, and G = g3*g2,  return d g1/ dg2 = G = g3*g2 instead of 2 g2*g3. 
+# Arguments:
+- `diag::Graph{F,W}`:  Target graph
+"""
+
 function node_derivative(g1::Graph{F,W}, g2::Graph{F,W}) where {F,W} #return d g1/ d g2 
     if isleaf(g1)
         return nothing
     elseif g1.operator == Sum
         sum_factor = 0.0
         exist = false #track if g2 exist in g1 subgraphs.
-        for i in 1:length(g1.subgraphs)
+        for i in eachindex(g1.subgraphs)
             if g1.subgraphs[i].id == g2.id
                 exist = true
                 sum_factor += g1.subgraph_factors[i]
@@ -152,7 +169,7 @@ function node_derivative(g1::Graph{F,W}, g2::Graph{F,W}) where {F,W} #return d g
         subgraphfactors = []
         factor = nothing
         first_time = true #Track if its the first time we find g2 in g1 subgraph.
-        for i in 1:length(g1.subgraphs)
+        for i in eachindex(g1.subgraphs)
             if g1.subgraphs[i].id == g2.id
                 if first_time # We should remove the first g2 in g1
                     first_time = false
@@ -284,6 +301,14 @@ function build_all_leaf_derivative(diag::Graph{F,W}, max_order::Int) where {F,W}
     return result
 end
 
+# function build_all_variable_derivative(diag::Graph{F,W}, max_order::Int, variable_number::Int) where {F,W}
+#     leaf_derivative, leafmap = build_all_leaf_derivative(diag, max_order)
+#     for (id, idx) in leafmap
+#         for order in max_order
+#             for 
+#         end
+#     end
+# end
 
 
 function forwardAD_root(diags::AbstractVector{G}) where {G<:Graph}