refactor: is_valid -> get_size()

1 files changed, 10 insertions, 7 deletions

diff --git a/src/genome/genome.js b/src/genome/genome.js
index 3445fe9..71e18c1 100644
--- a/src/genome/genome.js
+++ b/src/genome/genome.js
@@ -9,7 +9,8 @@ export const mutation_type = Object.freeze({
 });

 

 

-function positive(x) {

+// clamp a number in the range [0, infinity)

+function nonneg(x) {

   if (x < 0) { 

     return 0; 

   } else {

@@ -18,6 +19,7 @@ function positive(x) {
 }

 

 

+// mutate a gene

 export function mutate(gene, type, value) {

   const [ source, sink, weight ] = gene;

 

@@ -27,14 +29,14 @@ export function mutate(gene, type, value) {
 

     case mutation_type.source:

       if (value <= 0.5) {

-        return [ positive(source-1), sink, weight ];

+        return [ nonneg(source-1), sink, weight ];

       } else {

         return [ source+1, sink, weight ];

       }

 

     case mutation_type.sink:

       if (value <= 0.5) {

-        return [ source, positive(sink-1), weight ];

+        return [ source, nonneg(sink-1), weight ];

       } else {

         return [ source, sink+1, weight ];

       }

@@ -49,7 +51,8 @@ export function mutate(gene, type, value) {
 }

 

 

-export function is_valid(num_input, num_output, genome) {

+// check if a given genome is valid and compute its size

+export function get_size(num_input, num_output, genome) {

   const [ max_index, max_weight ] = genome.reduce(

     ([max_index, max_weight ], [ source, sink, weight]) => [

       Math.max(max_index, source, sink),

@@ -59,12 +62,12 @@ export function is_valid(num_input, num_output, genome) {
   );

 

   if (max_index < num_input + num_output - 1) {

-    return false;

+    return -1;

   }

   else if (max_weight > 4.0) {

-    return false;

+    return -1;

   }

   else {

-    return true;

+    return max_index + 1;

   }

 }