acerix / cnum

import {rationalApproximation, pathToValue, continuedFraction} from './SternBrocotTree'

test('Rational number for 13/7 is as expected', () => {

  expect(rationalApproximation(13/7).toString()).toBe('13/7')

})

test('Path to 1 is empty', () => {

  const a = 1

  const n = pathToValue(a).next()

  expect(n.value).toBeUndefined()

  expect(n.done).toBe(true)

})

test('Path to 3/7 is as expected', () => {

  const a = 3/7

  const ex = [false, false, true, true]

  const r = []

  for (const n of pathToValue(a)) {

    r.push(n)

  }

  expect(r).toStrictEqual(ex)

})

test('Continued fraction for Φ is all ones', () => {

  const Φ = (1 + Math.sqrt(5)) / 2

  const ex = Array(38).fill(1)

  const r = []

  for (const n of continuedFraction(Φ)) {

    r.push(n)

  }

  expect(r).toStrictEqual(ex)

})

test('Continued fraction for 355/113 is 3,7', () => {

  const a = 355/113

  const ex = [3, 7]

  const r = []

  for (const n of continuedFraction(a)) {

    r.push(n)

  }

  expect(r).toStrictEqual(ex)

})

test('Continued fraction for π is as expected', () => {

  const ex = [3, 7, 15, 1, 292, 1, 1, 1, 2, 1, 3, 1, 14]

  const r = []

  for (const n of continuedFraction(Math.PI)) {

    r.push(n)

  }

  expect(r).toStrictEqual(ex)

})

test('Continued fraction for e is as expected', () => {

  const ex = [2, 1, 2, 1, 1, 4, 1, 1, 6, 1, 1, 8, 1, 1, 10, 1, 1, 12, 1, 1]

  const r = []

  for (const n of continuedFraction(Math.E)) {

    r.push(n)

  }

  expect(r).toStrictEqual(ex)

})

test('Continued fraction for √2 is as expected', () => {

  const ex = [1].concat( Array(20).fill(2) )

  const r = []

  for (const n of continuedFraction(Math.SQRT2)) {

    r.push(n)

  }

  expect(r).toStrictEqual(ex)

})