From a32853e60029fa7f08d4d713ee613ee03196fbef Mon Sep 17 00:00:00 2001
From: sanine <sanine.not@pm.me>
Date: Mon, 30 Oct 2023 01:18:23 -0500
Subject: add mut_genome_contract

---
 src/genome/genome.js | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

(limited to 'src/genome/genome.js')

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, 
-- 
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