Merge pull request #1238

* [#187531276] Feature: CODAP provides randomBinomial and randomNormal

* chore: code review tweaks

* * Adding tests for randomNormal and randomBinomial

v3/package.json

@@ -23,7 +23,7 @@
     },
     "transformIgnorePatterns": [
       "/comments/ESM-only (https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c) modules that should not be transformed by ts-jest",
-      "/node_modules/(?!(color-parse|d3|d3-(.+)|decode-uri-component|delaunator|escape-string-regexp|filter-obj|internmap|mime|nanoid|query-string|@?react-leaflet|robust-predicates|split-on-first)/)"
+      "/node_modules/(?!(d3|d3-(.+)|decode-uri-component|delaunator|escape-string-regexp|filter-obj|internmap|mime|nanoid|query-string|random|@?react-leaflet|robust-predicates|split-on-first)/)"
     ],
     "setupFilesAfterEnv": [
       "<rootDir>/src/test/setupTests.ts"
@@ -198,6 +198,7 @@
     "pixi.js": "~7.3.3",
     "pluralize": "^8.0.0",
     "query-string": "^8.2.0",
+    "random": "^4.1.0",
     "react": "^18.2.0",
     "react-colorful": "^5.6.1",
     "react-data-grid": "7.0.0-beta.42",

v3/src/models/formula/functions/other-functions.test.ts

@@ -38,3 +38,24 @@ describe("random", () => {
     expect(result).toBeLessThanOrEqual(20)
   })
 })
+
+describe("randomNormal", () => {
+  it("returns random numbers between with a mean of 10 and a standard deviation of 5", () => {
+    const fn = math.compile("randomNormal(10, 5)")
+    const numbers = Array.from({ length: 1000 }, () => fn.evaluate()),
+      mean = numbers.reduce((a, b) => a + b) / numbers.length,
+      stdDev = Math.sqrt(numbers.reduce((a, b) => a + (b - mean) ** 2) / numbers.length)
+    expect(mean).toBeGreaterThanOrEqual(9.5)
+    expect(mean).toBeLessThanOrEqual(10.5)
+    expect(stdDev).toBeGreaterThanOrEqual(4)
+    expect(stdDev).toBeLessThanOrEqual(6)
+  })
+})
+
+describe("randomBinomial", () => {
+  it("returns random integers between 0 and 5", () => {
+    const fn = math.compile("randomBinomial(5, 0.5)")
+    const integers = Array.from({ length: 100 }, () => fn.evaluate())
+    expect(integers.every((n) => Math.round(n) === n && n >= 0 && n <= 5)).toBeTruthy()
+  })
+})

v3/src/models/formula/functions/other-functions.ts

@@ -1,6 +1,9 @@
-import { pickRandom, random } from "mathjs"
+import { pickRandom } from "mathjs"
+import { Random } from "random"
 import { FValue } from "../formula-types"
 
+const randomGen = new Random()
+
 export const otherFunctions = {
   // if(expression, value_if_true, value_if_false)
   if: {
@@ -21,7 +24,30 @@ export const otherFunctions = {
   random: {
     numOfRequiredArguments: 0,
     isRandomFunction: true,
-    // Nothing to do here, mathjs.random() has exactly the same signature as CODAP V2 random() function.
-    evaluate: (...args: FValue[]) => random(...args as number[])
-  }
+    // Nothing to do here, Random.float() has exactly the same signature as CODAP V2 random() function.
+    evaluate: (...args: FValue[]) => randomGen.float(...args as number[])
+  },
+
+  // randomNormal(mean, standard_deviation) Returns a random number drawn from a normal distribution which, by default,
+  // has a mean of 0 and a standard deviation of 1.
+  randomNormal: {
+    numOfRequiredArguments: 0,
+    isRandomFunction: true,
+    // Nothing to do here, Random.normal() has exactly the same signature as CODAP V2 randomNormal() function.
+    evaluate: (...args: FValue[]) => {
+      return randomGen.normal(...args as number[])()
+    }
+  },
+
+  // randomBinomial(n, p) Returns a random integer drawn from a binomial distribution with n independent draws
+  // (or experiments) each with probability p of success. Defaults are n = 1, p = 0.5.
+  randomBinomial: {
+    numOfRequiredArguments: 0,
+    isRandomFunction: true,
+    // Nothing to do here, Random.binomial() has exactly the same signature as CODAP V2 randomBinomial() function.
+    evaluate: (...args: FValue[]) => {
+      return randomGen.binomial(...args as number[])()
+    }
+  },
+
 }