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https://github.com/josdejong/mathjs.git
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f79fec6db5
* fix toTex(): remove row delimiter on the last row * remove row delimiter on the last row (use map and join instead of forEach) * fix ArrayNode.toTex() unit tests incorrectly expecting a row delimiter on the last row * added toTex() tests for nested cases * fixed ArrayNode.toTex() for nested cases * removed redunant variable
127 lines
3.9 KiB
JavaScript
127 lines
3.9 KiB
JavaScript
// test inv
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import assert from 'assert'
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import approx from '../../../../tools/approx.js'
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import math from '../../../../src/defaultInstance.js'
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const inv = math.inv
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describe('inv', function () {
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it('should return the inverse of a number', function () {
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assert.deepStrictEqual(inv(4), 1 / 4)
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assert.deepStrictEqual(inv(math.bignumber(4)), math.bignumber(1 / 4))
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})
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it('should return the inverse of a matrix with just one value', function () {
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assert.deepStrictEqual(inv([4]), [1 / 4])
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assert.deepStrictEqual(inv([[4]]), [[1 / 4]])
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})
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it('should return the inverse for each element in an array', function () {
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assert.deepStrictEqual(inv([4]), [1 / 4])
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assert.deepStrictEqual(inv([[4]]), [[1 / 4]])
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approx.deepEqual(inv([
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[1, 4, 7],
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[3, 0, 5],
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[-1, 9, 11]
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]), [
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[5.625, -2.375, -2.5],
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[4.75, -2.25, -2],
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[-3.375, 1.625, 1.5]
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])
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approx.deepEqual(inv([
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[2, -1, 0],
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[-1, 2, -1],
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[0, -1, 2]
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]), [
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[3 / 4, 1 / 2, 1 / 4],
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[1 / 2, 1, 1 / 2],
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[1 / 4, 1 / 2, 3 / 4]
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])
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// the following will force swapping of empty rows in the middle of the matrix
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approx.deepEqual(inv([
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[1, 0, 0],
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[0, 0, 1],
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[0, 1, 0]
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]), [
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[1, 0, 0],
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[0, 0, 1],
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[0, 1, 0]
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])
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approx.deepEqual(inv([
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[1, 0, 0],
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[0, -1, 1],
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[0, 0, 1]
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]), [
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[1, 0, 0],
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[0, -1, 1],
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[0, 0, 1]
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])
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})
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it('should return the inverse for each element in a matrix', function () {
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assert.deepStrictEqual(inv(math.matrix([4])), math.matrix([1 / 4]))
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assert.deepStrictEqual(inv(math.matrix([[4]])), math.matrix([[1 / 4]]))
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assert.deepStrictEqual(inv(math.matrix([[4]], 'sparse')), math.matrix([[1 / 4]], 'sparse'))
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assert.deepStrictEqual(inv(math.matrix([[1, 2], [3, 4]], 'sparse')), math.matrix([[-2, 1], [1.5, -0.5]], 'sparse'))
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})
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it('should throw an error in case of non-square matrices', function () {
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assert.throws(function () { inv([1, 2, 3]) }, /Matrix must be square/)
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assert.throws(function () { inv([[1, 2, 3], [4, 5, 6]]) }, /Matrix must be square/)
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})
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it('should throw an error in case of multi dimensional matrices', function () {
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assert.throws(function () { inv([[[1, 2, 3], [4, 5, 6]]]) }, /Matrix must be two dimensional/)
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})
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it('should throw an error in case of non-invertable matrices', function () {
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assert.throws(function () { inv([[0]]) }, /Cannot calculate inverse, determinant is zero/)
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assert.throws(function () { inv([[1, 0], [0, 0]]) }, /Cannot calculate inverse, determinant is zero/)
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assert.throws(function () { inv([[1, 1, 1], [1, 0, 0], [0, 0, 0]]) }, /Cannot calculate inverse, determinant is zero/)
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})
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it('should throw an error in case of wrong number of arguments', function () {
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assert.throws(function () { inv() }, /TypeError: Too few arguments/)
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assert.throws(function () { inv([], []) }, /TypeError: Too many arguments/)
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})
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it('should throw an error in case of invalid type of arguments', function () {
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assert.throws(function () { math.concat(inv(new Date())) }, /TypeError: Unexpected type of argument/)
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})
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it('should avoid issues with elements that are almost zero', function () {
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approx.deepEqual(inv([
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[0, 1, 0, 788],
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[-1, 0, 0, 692],
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[0, 0, 1, 0],
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[0, 0, 0, 1]
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]), [
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[0, -1, 0, 692],
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[1, 0, 0, -788],
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[0, 0, 1, 0],
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[0, 0, 0, 1]
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])
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approx.deepEqual(inv([
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[6.123233995736766e-17, 1, 0, 788],
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[-1, 6.123233995736766e-17, 0, 692],
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[0, 0, 1, 0],
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[0, 0, 0, 1]
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]), [
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[6.123233995736766e-17, -1, 0, 692],
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[1, 6.123233995736766e-17, 0, -788],
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[0, 0, 1, 0],
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[0, 0, 0, 1]
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])
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})
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it('should LaTeX inv', function () {
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const expression = math.parse('inv([[1,2],[3,4]])')
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assert.strictEqual(expression.toTex(), '\\left(\\begin{bmatrix}1&2\\\\3&4\\end{bmatrix}\\right)^{-1}')
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})
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})
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