test: better float judgement

packages/visual-insights/test/impurityMeasure.js

@@ -1,51 +1,55 @@
 const assert = require('assert');
 const { Statistics } = require('../build/cjs/index');
 const { normalize, gini, entropy } = Statistics;
+
+function floatEqual (n1, n2) {
+  return Math.abs(n1 - n2) < Number.EPSILON * (2 ** 2);
+}
+
+function getRandomArray (size = 2 + Math.round(Math.random() * 1000)) {
+  let frequencyList = [];
+  for (let i = 0; i < size; i++) {
+    frequencyList.push(Math.round(Math.random() * 1000));
+  }
+  return frequencyList;
+}
+
 describe('Impurity Measure test', function () {
   describe('function: normalize', function () {
+    let frequencyList = [1,2,3,4,5];//getRandomArray();
+    const probabilityList = normalize(frequencyList);
+    it('values checks', function () {
+      let freSum = 0;
+      frequencyList.forEach(f => freSum += f);
+      probabilityList.forEach((p, i) => {
+        assert.equal(floatEqual(p, frequencyList[i] / freSum), true)
+      })
+    })
     it('sum_{p} = 1', function () {
-      const size = 2 + Math.round(Math.random() * 100);
-      let frequencyList = [];
-      for (let i = 0; i < size; i++) {
-        frequencyList.push(Math.round(Math.random() * 1000));
-      }
-      const probabilityList = normalize(frequencyList);
-
       let sum = 0;
-      for (let p of probabilityList) {
-        sum += p;
-      }
-      assert.equal(Math.abs(1 - sum) < Number.EPSILON * Math.pow(2, 2) * probabilityList.length, true);
-      // assert.equal(Math.abs(1 - sum) < 0.001, true);
+      probabilityList.forEach(p => sum += p);
+      assert.equal(floatEqual(sum, 1), true);
     })
   })
 
   describe('function: entropy', function () {
+    let size = 100 + Math.round(Math.random() * 100);
+    let frequencyList = getRandomArray(size);
+    const probabilityList = normalize(frequencyList);
+    let ans = entropy(probabilityList);
+    it('isNumber', function () {
+      assert.notEqual(ans, NaN);
+    })
     it('value <=log(k)', function () {
-        const size = 2 + Math.round(Math.random() * 100);
-        let frequencyList = [];
-        for (let i = 0; i < size; i++) {
-          frequencyList.push(Math.round(Math.random() * 1000));
-        }
-        const probabilityList = normalize(frequencyList);
-
-        let ans = entropy(probabilityList);
-        assert.notEqual(ans, NaN);
-        assert.equal(Math.log2(size) + Number.EPSILON >= ans - Number.EPSILON, true);
-      })
+      assert.equal(Math.log2(size) + Number.EPSILON * (2 ** 3) >= ans - Number.EPSILON * (2 ** 3), true);
+    })
   })
 
   describe('function: gini', function () {
+    let frequencyList = getRandomArray();
+    let probabilityList = normalize(frequencyList);
+    let ans = gini(probabilityList);
     it('value <= 1', function () {
-        const size = 2 + Math.round(Math.random() * 100);
-        let frequencyList = [];
-        for (let i = 0; i < size; i++) {
-          frequencyList.push(Math.round(Math.random() * 1000));
-        }
-        const probabilityList = normalize(frequencyList);
-
-        let ans = gini(probabilityList);
-
         assert.equal(ans <= 1, true);
       })
   })