1 files changed, 19 insertions, 0 deletions
diff --git a/src/genome/genome.js b/src/genome/genome.js
index 16b5e4d..d2650b5 100644
--- a/src/genome/genome.js
+++ b/src/genome/genome.js
@@ -106,6 +106,25 @@ export function mut_genome_expand(
 }
 
 
+export function mut_genome_contract(
+  [n_input, n_internal, n_output, genome], r
+) {
+  const contract_idx = Math.floor(n_internal * r) + n_input;
+  const new_source = (source) => source >= contract_idx ? source-1 : source;
+  const new_sink   = (sink)   => sink > contract_idx ? sink-1 : sink;
+
+  const new_genome = genome.map(([source, sink, weight]) => [
+    new_source(source), 
+    new_sink(sink), 
+    weight,
+  ]);
+
+  return [
+    n_input, n_internal-1, n_output, new_genome
+  ];
+}
+
+
 export function mut_genome_insert(
   [n_input, n_internal, n_output, genome], 
   weight_max,