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95 lines
4.1 KiB
JavaScript
95 lines
4.1 KiB
JavaScript
const assert = require('assert')
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const approx = require('../../../tools/approx')
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const math = require('../../../src/main')
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const factorial = math.factorial
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describe('factorial', function () {
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it('should calculate the factorial of a number', function () {
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assert.equal(factorial(0), 1)
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assert.equal(factorial(1), 1)
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assert.equal(factorial(2), 2)
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assert.equal(factorial(3), 6)
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assert.equal(factorial(4), 24)
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assert.equal(factorial(5), 120)
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assert.ok(!isFinite(factorial(Number.MAX_VALUE))) // shouldn't stall
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assert.ok(!isFinite(factorial(Infinity)))
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})
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it('should calculate the factorial of a bignumber', function () {
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const bigmath = math.create({number: 'BigNumber', precision: 5})
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const bigfactorial = bigmath.factorial
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const bignumber = bigmath.bignumber
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assert.deepEqual(bigfactorial(bignumber(0)), bignumber(1))
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assert.deepEqual(bigfactorial(bignumber(Infinity)).toString(), 'Infinity')
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assert.deepEqual(bigfactorial(bignumber(11)), bignumber(39917000))
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assert.deepEqual(bigfactorial(bignumber(22)), bignumber(1.124e+21))
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bigmath.config({precision: 20})
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assert.deepEqual(bigfactorial(bignumber(5)), bignumber(120))
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assert.deepEqual(bigfactorial(bignumber(19)), bignumber(121645100408832000))
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assert.deepEqual(bigfactorial(bignumber(20)), bignumber(2432902008176640000))
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assert.deepEqual(bigfactorial(bignumber(21)), bignumber('51090942171709440000'))
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assert.deepEqual(bigfactorial(bignumber(25)), bignumber('1.5511210043330985984e+25'))
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assert.deepEqual(bigfactorial(bignumber(24)), bignumber('6.2044840173323943936e+23'))
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assert.deepEqual(bigfactorial(bignumber(22)), bignumber('1124000727777607680000'))
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bigmath.config({precision: 5})
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assert.deepEqual(bigfactorial(bignumber(11)), bignumber(39917000))
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assert.deepEqual(bigfactorial(bignumber(22)), bignumber(1.124e+21))
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assert.deepEqual(bigfactorial(bignumber(24)), bignumber(6.2045e+23))
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assert.deepEqual(bigfactorial(bignumber(21)), bignumber(5.1091e+19))
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assert.deepEqual(bigfactorial(bignumber(26)), bignumber(4.0329e+26))
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bigmath.config({precision: 20})
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assert.deepEqual(bigfactorial(bignumber(3000)), bignumber('4.1493596034378540856e+9130'))
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})
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it('should calculate the factorial of a boolean', function () {
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assert.equal(factorial(true), 1)
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assert.equal(factorial(false), 1)
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})
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it('should calculate the factorial of each element in a matrix', function () {
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assert.deepEqual(factorial(math.matrix([0, 1, 2, 3, 4, 5])), math.matrix([1, 1, 2, 6, 24, 120]))
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})
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it('should calculate the factorial of each element in an array', function () {
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assert.deepEqual(factorial([0, 1, 2, 3, 4, 5]), [1, 1, 2, 6, 24, 120])
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})
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it('should calculate the factorial of a non-integer', function () {
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approx.equal(factorial(1.5), 1.32934038817913702047362561)
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approx.equal(factorial(7.5), 14034.40729348)
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})
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it('should throw error if called with negative number', function () {
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assert.throws(function () { factorial(-1) }, /Value must be non-negative/)
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assert.throws(function () { factorial(-1.5) }, /Value must be non-negative/)
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assert.throws(function () { factorial(math.bignumber(-1)) }, /Value must be non-negative/)
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assert.throws(function () { factorial(math.bignumber(-1.5)) }, /Value must be non-negative/)
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assert.throws(function () { factorial(math.bignumber(-Infinity)) }, /Value must be non-negative/)
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})
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it('should throw an error if called with non-integer bignumber', function () {
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assert.throws(function () { factorial(math.bignumber(1.5)) })
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})
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it('should throw en error if called with invalid number of arguments', function () {
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assert.throws(function () { factorial() })
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assert.throws(function () { factorial(1, 3) })
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})
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it('should throw en error if called with invalid type of argument', function () {
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assert.throws(function () { factorial(new Date()) })
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assert.throws(function () { factorial('a string') })
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})
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it('should LaTeX factorial', function () {
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const expression = math.parse('factorial(6)')
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assert.equal(expression.toTex(), '\\left(6\\right)!')
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})
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})
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