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112 lines
3.8 KiB
JavaScript
112 lines
3.8 KiB
JavaScript
import assert from 'assert'
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import math from '../../../../src/bundleAny'
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import actualErfValues from './erf.values.json'
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const erf = math.erf
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const DIFF_THRESH = 5e-16
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describe('erf', function () {
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it('should calculate erf(x), |x| < 0.46875', function () {
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let i, diff, actual, expected
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for (i = -4; i <= 4; i += 1) {
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actual = erf(i / 10)
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expected = actualErfValues[(i / 10).toFixed(1)]
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diff = Math.abs(actual - expected)
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assert.ok(diff < DIFF_THRESH, [i, actual, expected, diff])
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}
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})
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it('should calculate erf(x), 0.46875 <= |x| <= 4', function () {
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let i, diff, actual, expected
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for (i = -40; i < -4; i += 1) {
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actual = erf(i / 10)
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expected = actualErfValues[(i / 10).toFixed(1)]
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diff = Math.abs(actual - expected)
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assert.ok(diff < DIFF_THRESH, [i, actual, expected, diff])
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}
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for (i = 5; i <= 40; i += 1) {
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actual = erf(i / 10)
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expected = actualErfValues[(i / 10).toFixed(1)]
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diff = Math.abs(actual - expected)
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assert.ok(diff < DIFF_THRESH, [i, actual, expected, diff])
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}
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})
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it('should calculate erf(x), |x| > 4', function () {
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let i, diff, actual, expected
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for (i = -70; i < -40; i += 1) {
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actual = erf(i / 10)
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expected = actualErfValues[(i / 10).toFixed(1)]
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diff = Math.abs(actual - expected)
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assert.ok(diff < DIFF_THRESH, [i, actual, expected, diff])
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}
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for (i = 41; i < 70; i += 1) {
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actual = erf(i / 10)
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expected = actualErfValues[(i / 10).toFixed(1)]
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diff = Math.abs(actual - expected)
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assert.ok(diff < DIFF_THRESH, [i, actual, expected, diff])
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}
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})
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it('should calculate the erf of a nonpositive integer', function () {
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assert.ok(Math.abs(erf(-1) - actualErfValues['-1.0']) < DIFF_THRESH)
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assert.ok(Math.abs(erf(-2) - actualErfValues['-2.0']) < DIFF_THRESH)
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assert.ok(Math.abs(erf(-3) - actualErfValues['-3.0']) < DIFF_THRESH)
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})
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it('should calculate the erf of a boolean (true = 1, false = 0)', function () {
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assert.ok(Math.abs(erf(true) - actualErfValues['1.0']) < DIFF_THRESH)
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assert.ok(Math.abs(erf(false) - actualErfValues['0.0']) < DIFF_THRESH)
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})
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it('should calculate the erf of each element in a matrix', function () {
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math.subtract(
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erf(math.matrix([0, 1, 2, 3, 4, 5])),
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math.matrix([0, 1, 2, 3, 4, 5].map(function (x) {
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return actualErfValues[x.toFixed(1)]
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}))
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).forEach(function (diff) {
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assert.ok(diff < DIFF_THRESH)
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})
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})
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it('should calculate the erf of each element in an array', function () {
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math.subtract(
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erf(math.matrix([0, 1, 2, 3, 4, 5])),
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math.matrix([0, 1, 2, 3, 4, 5].map(function (x) {
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return actualErfValues[x.toFixed(1)]
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}))
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).forEach(function (diff) {
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assert.ok(diff < DIFF_THRESH)
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})
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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 () { erf() })
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assert.throws(function () { erf(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 () { erf(new Date()) })
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assert.throws(function () { erf('a string') })
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})
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it('should LaTeX erf', function () {
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const expression = math.parse('erf(2.5)')
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assert.strictEqual(expression.toTex(), 'erf\\left(2.5\\right)')
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})
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it('should return 1 for numbers greater than 2**53 (including Infinity)', function () {
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assert.strictEqual(erf(Math.pow(2, 53)), 1)
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assert.strictEqual(erf(Infinity), 1)
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})
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it('should return -1 for numbers less than -2**53 (including -Infinity)', function () {
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assert.strictEqual(erf(-Math.pow(2, 53)), -1)
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assert.strictEqual(erf(-Infinity), -1)
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})
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// TODO: Test with nums really close to 0
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// TODO: Once this works for complex numbers and imaginary units, test
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})
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