add some better comments

1 files changed, 15 insertions, 7 deletions

diff --git a/src/mind/topology.js b/src/mind/topology.js
index 7e58718..5d4d52c 100644
--- a/src/mind/topology.js
+++ b/src/mind/topology.js
@@ -106,27 +106,34 @@ function edge_ends(n, edge) {
 // recursively get the value of a node from the input nodes,
 // optionally caching the computed values
 function get_value(n, index, input, prev, cache) {
+	// check if value is cached
 	if (cache !== undefined && cache[index]) {
 		return cache[index];
 	}
+	// check if value is input
 	if (is_input(n, index)) {
 		return input[index];
 	}
-	const adj = n.adjacency[index];
-	const incident = incident_edges(n, adj);	
-	const weight = incident.map(x => n.weight[x]);
-	const sources = incident
+
+	const adj = n.adjacency[index];                // get adjacency list
+	const incident = incident_edges(n, adj);	   // get incident edges
+	const weight = incident.map(x => n.weight[x]); // edge weights
+	const sources = incident                       // get ancestor nodes
 		.map(x => edge_ends(n, x).source);
 	
-	const values = sources
-		.map(x => x === index ? prev[x - n.input_count] : get_value(n, x, input, prev, cache));
+	const values = sources            // get the value of each ancestor
+		.map(x => x === index         // if the ancestor is this node
+			? prev[x - n.input_count] // then the value is the previous value
+			: get_value(n, x, input, prev, cache)); // else recurse
 	
-	const sum = values
+	const sum = values // compute the weighted sum of the values
 		.reduce((acc, x, i) => acc + (weight[i] * x), 0);
 
+	// compute result
 	const value = Math.tanh(sum);
 
 	// !!! impure caching !!!
+	// cache result
 	if (cache !== undefined) {
 		cache[index] = value;
 	}
@@ -142,6 +149,7 @@ function network_compute(n, input, state) {
 	if (input.length !== n.input_count) {
 		throw new Error("incorrect number of input elements");
 	}
+	// validate state
 	const hidden_count = n.adjacency.length - n.input_count - n.output_count;
 	if (state.length !== hidden_count) {
 		throw new Error("incorrect number of state elements");