2 files changed, 41 insertions, 0 deletions
diff --git a/src/genome/genome.js b/src/genome/genome.js
index 7688b32..d35b68c 100644
--- a/src/genome/genome.js
+++ b/src/genome/genome.js
@@ -104,3 +104,19 @@ export function mut_genome_expand(
     n_input, n_internal+1, n_output, new_genome,
   ];
 }
+
+
+export function mut_genome_insert(
+  [n_input, n_internal, n_output, genome], 
+  weight_max, 
+  r1, r2, r3
+) {
+  const source = Math.floor((n_input + n_internal) * r1);
+  const sink   = Math.floor((n_internal + n_output) * r2) + n_input;
+  const weight = weight_max * ((2*r3)-1);
+
+  return [
+    n_input, n_internal, n_output,
+    [...genome, [source, sink, weight]],
+  ];
+}
diff --git a/src/genome/genome.test.js b/src/genome/genome.test.js
index 11b2d31..d7dbe72 100644
--- a/src/genome/genome.test.js
+++ b/src/genome/genome.test.js
@@ -7,6 +7,7 @@ import {
   mut_gene_sink,
   mut_gene_weight,
   mut_genome_expand,
+  mut_genome_insert,
 } from './genome';
 
 
@@ -161,3 +162,27 @@ test('expand genome', () => {
     ],
   ]);
 });
+
+
+test('insert new genes', () => {
+  const n_input = 1;
+  const n_internal = 2;
+  const n_output = 1;
+  const weight_max = 4;
+
+  expect(mut_genome_insert([
+    n_input, n_internal, n_output,
+    []
+  ], weight_max, 0, 0.5, 0)).toEqual([
+    n_input, n_internal, n_output,
+    [[0, 2, -4]]
+  ]);
+
+  expect(mut_genome_insert([
+    n_input, n_internal, n_output,
+    [[0, 2, -4]]
+  ], weight_max, 0.99, 0, 1)).toEqual([
+    n_input, n_internal, n_output,
+    [[0, 2, -4], [2, 1, 4]]
+  ]);
+});