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https://github.com/josdejong/mathjs.git
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f6d3e9ea8d
* feat: add polynomialRoot function This is intended as a benchmark for general arithmetic/basic algebra functionality of mathjs, but was chosen to be something of potential independent utility as well, worth adding to mathjs in its own right. Currently ol=nly computes the numerical roots for real or complex polynomials of degree three or less. As usual, adds documentation, embedded documentation, tests, TypeScript declaration, and TypeScript tests. Also updates doc.test.js to make it easier to specify an array of complex numbers as the expected output, and comapres with the appropriate fuzz in such cases. Finally, adds a benchmark that computes the roots of all cubics with nonnegative integer coefficients no larger than five. * doc: fix typo in polynomialRoot embedded docs Thanks, SamuelTLG * style: avoid slightly cryptic Boolean flag stand-in
54 lines
2.2 KiB
JavaScript
54 lines
2.2 KiB
JavaScript
import approx from '../../../../tools/approx.js'
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import math from '../../../../src/defaultInstance.js'
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const complex = math.complex
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const pRoot = math.polynomialRoot
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describe('polynomialRoot', function () {
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it('should solve a linear equation with real or complex coefficients',
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function () {
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approx.deepEqual(pRoot(6, 3), [-2])
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approx.deepEqual(pRoot(complex(-3, 2), 2), [complex(1.5, -1)])
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approx.deepEqual(pRoot(complex(3, 1), complex(-1, -1)), [complex(2, -1)])
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})
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it('should solve a quadratic equation with a double root', function () {
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approx.deepEqual(pRoot(4, 4, 1), [-2])
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approx.deepEqual(pRoot(complex(0, 2), complex(2, 2), 1), [complex(-1, -1)])
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})
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it('should solve a quadratic with two distinct roots', function () {
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approx.deepEqual(pRoot(-3, 2, 1), [1, -3])
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approx.deepEqual(pRoot(-2, 0, 1), [math.sqrt(2), -math.sqrt(2)])
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approx.deepEqual(
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pRoot(4, 2, 1), [complex(-1, math.sqrt(3)), complex(-1, -math.sqrt(3))])
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approx.deepEqual(
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pRoot(complex(3, 1), -3, 1), [complex(2, -1), complex(1, 1)])
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})
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it('should solve a cubic with a triple root', function () {
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approx.deepEqual(pRoot(8, 12, 6, 1), [-2])
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approx.deepEqual(
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pRoot(complex(-2, 11), complex(9, -12), complex(-6, 3), 1),
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[complex(2, -1)])
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})
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it('should solve a cubic with one simple and one double root', function () {
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approx.deepEqual(pRoot(4, 0, -3, 1), [-1, 2])
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approx.deepEqual(
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pRoot(complex(9, 9), complex(15, 6), complex(7, 1), 1),
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[complex(-1, -1), -3])
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approx.deepEqual(
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pRoot(complex(0, 6), complex(6, 8), complex(5, 2), 1),
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[-3, complex(-1, -1)])
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approx.deepEqual(
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pRoot(complex(2, 6), complex(8, 6), complex(5, 1), 1),
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[complex(-3, 1), complex(-1, -1)])
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})
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it('should solve a cubic with three distinct roots', function () {
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approx.deepEqual(pRoot(6, 11, 6, 1), [-3, -1, -2])
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approx.deepEqual(
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pRoot(-1, -2, 0, 1), [-1, (1 + math.sqrt(5)) / 2, (1 - math.sqrt(5)) / 2])
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approx.deepEqual(pRoot(1, 1, 1, 1), [-1, complex(0, -1), complex(0, 1)])
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approx.deepEqual(
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pRoot(complex(0, -10), complex(8, 12), complex(-6, -3), 1),
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[complex(1, 1), complex(3, 1), complex(2, 1)])
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})
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})
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