Fix fitness calculation

draft

@@ -0,0 +1,14 @@
+const genesO = 'hellaworld';
+const genes: number[] = [];
+
+for (let i = 0; i < genesO.length; i += 1) {
+  genes.push(genesO.charCodeAt(i) - 97);
+}
+
+for (let i = 0; i < genes.length; i += 1) {
+  const charCode = answer.charCodeAt(i) - 97;
+  const geneCharCode = Math.floor(genes[i]);
+  sum += Math.abs(charCode - geneCharCode);
+}
+
+console.log(sum);

src/core/Population.ts

@@ -35,7 +35,7 @@ export class Population {
   }
 
   selectBestChromosomes() {
-    const pivot = Math.floor(this.size / 3);
+    const pivot = Math.floor(this.chromosomes.length / 3);
     this.chromosomes.splice(2 * pivot);
 
     this.sumFitness = 0;
@@ -45,20 +45,27 @@ export class Population {
   }
 
   crossoverChromosomes() {
+    let newChromosomes = [];
     for (let i = this.chromosomes.length; i < this.size; i += 1) {
-      const chromosomeA = this.getRandomChromosome();
-      const chromosomeB = this.getRandomChromosome();
+      let chromosomeA = null;
+      let chromosomeB = null;
+
+      do {
+        chromosomeA = this.getRandomChromosome();
+        chromosomeB = this.getRandomChromosome();
+      } while (!chromosomeA || !chromosomeB);
 
       if (chromosomeA && chromosomeB) {
         const pivot = Math.floor(Math.random() * chromosomeA.getLength());
         const genesA = chromosomeA.getGenes().slice(0, pivot);
         const genesB = chromosomeB.getGenes().slice(pivot);
         const newChromosome = Chromosome.fromDNA([...genesA, ...genesB]);
-        this.chromosomes.push(newChromosome);
+        newChromosomes.push(newChromosome);
       } else {
-        console.error('Should not happen');
+        // console.error('Should not happen');
       }
     }
+    this.chromosomes = [...this.chromosomes, ...newChromosomes];
   }
 
   mutateChromosones() {
@@ -85,7 +92,7 @@ export class Population {
   run(times: number = 1) {
     for (let i = 0; i < times; i += 1) {
       this.process();
-      console.log(`Generation ${i}: ${this.chromosomes[0].getFitness()}`);
+      console.log(`Generation ${i}: ${this.chromosomes[0].getFitness()} (remaining: ${this.chromosomes.length})`);
     }
     let finalString = '';
     this.chromosomes[0].getGenes().map((gene: Gene) => {

src/example.ts

@@ -2,23 +2,23 @@ import { Population } from './core/Population';
 import { Blueprint } from './core/Blueprint';
 import { Gene } from './core/Gene';
 
-const answer = 'helloworld';
+const answer = 'helloworldhowareyoutoday';
 
 const blueprint = new Blueprint();
 blueprint.add(26, answer.length);
 
-const population = new Population(10, blueprint);
+const population = new Population(500, blueprint);
 
 population.setFitnessCalculation((genes: Gene[]) => {
-  let sum = 0;
+  let sum = 1;
 
   for (let i = 0; i < genes.length; i += 1) {
     const charCode = answer.charCodeAt(i) - 97;
     const geneCharCode = Math.floor(genes[i].get());
-    sum += Math.abs(charCode - geneCharCode);
+    sum += charCode === geneCharCode ? 1 : 0;
   }
 
-  return 1 / sum;
+  return sum / genes.length;
 });
 
 population.run(1000);