simple-squiggle/node_modules/mathjs/lib/esm/function/arithmetic/nthRoots.js

117 lines
3.3 KiB
JavaScript

import { factory } from '../../utils/factory.js';
var name = 'nthRoots';
var dependencies = ['config', 'typed', 'divideScalar', 'Complex'];
export var createNthRoots = /* #__PURE__ */factory(name, dependencies, _ref => {
var {
typed,
config,
divideScalar,
Complex
} = _ref;
/**
* Each function here returns a real multiple of i as a Complex value.
* @param {number} val
* @return {Complex} val, i*val, -val or -i*val for index 0, 1, 2, 3
*/
// This is used to fix float artifacts for zero-valued components.
var _calculateExactResult = [function realPos(val) {
return new Complex(val, 0);
}, function imagPos(val) {
return new Complex(0, val);
}, function realNeg(val) {
return new Complex(-val, 0);
}, function imagNeg(val) {
return new Complex(0, -val);
}];
/**
* Calculate the nth root of a Complex Number a using De Movire's Theorem.
* @param {Complex} a
* @param {number} root
* @return {Array} array of n Complex Roots
*/
function _nthComplexRoots(a, root) {
if (root < 0) throw new Error('Root must be greater than zero');
if (root === 0) throw new Error('Root must be non-zero');
if (root % 1 !== 0) throw new Error('Root must be an integer');
if (a === 0 || a.abs() === 0) return [new Complex(0, 0)];
var aIsNumeric = typeof a === 'number';
var offset; // determine the offset (argument of a)/(pi/2)
if (aIsNumeric || a.re === 0 || a.im === 0) {
if (aIsNumeric) {
offset = 2 * +(a < 0); // numeric value on the real axis
} else if (a.im === 0) {
offset = 2 * +(a.re < 0); // complex value on the real axis
} else {
offset = 2 * +(a.im < 0) + 1; // complex value on the imaginary axis
}
}
var arg = a.arg();
var abs = a.abs();
var roots = [];
var r = Math.pow(abs, 1 / root);
for (var k = 0; k < root; k++) {
var halfPiFactor = (offset + 4 * k) / root;
/**
* If (offset + 4*k)/root is an integral multiple of pi/2
* then we can produce a more exact result.
*/
if (halfPiFactor === Math.round(halfPiFactor)) {
roots.push(_calculateExactResult[halfPiFactor % 4](r));
continue;
}
roots.push(new Complex({
r: r,
phi: (arg + 2 * Math.PI * k) / root
}));
}
return roots;
}
/**
* Calculate the nth roots of a value.
* An nth root of a positive real number A,
* is a positive real solution of the equation "x^root = A".
* This function returns an array of complex values.
*
* Syntax:
*
* math.nthRoots(x)
* math.nthRoots(x, root)
*
* Examples:
*
* math.nthRoots(1)
* // returns [
* // {re: 1, im: 0},
* // {re: -1, im: 0}
* // ]
* nthRoots(1, 3)
* // returns [
* // { re: 1, im: 0 },
* // { re: -0.4999999999999998, im: 0.8660254037844387 },
* // { re: -0.5000000000000004, im: -0.8660254037844385 }
* ]
*
* See also:
*
* nthRoot, pow, sqrt
*
* @param {number | BigNumber | Fraction | Complex} x Number to be rounded
* @return {number | BigNumber | Fraction | Complex} Rounded value
*/
return typed(name, {
Complex: function Complex(x) {
return _nthComplexRoots(x, 2);
},
'Complex, number': _nthComplexRoots
});
});