| 1 | import { factory } from '../../utils/factory'
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| 2 | import { deepMap } from '../../utils/collection'
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| 3 | import { signNumber } from '../../plain/number'
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| 4 |
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| 5 | const name = 'sign'
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| 6 | const dependencies = ['typed', 'BigNumber', 'Fraction', 'complex']
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| 7 |
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| 8 | export const createSign = /* #__PURE__ */ factory(name, dependencies, ({ typed, BigNumber, complex, Fraction }) => {
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| 9 | /**
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| 10 | * Compute the sign of a value. The sign of a value x is:
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| 11 | *
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| 12 | * - 1 when x > 0
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| 13 | * - -1 when x < 0
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| 14 | * - 0 when x == 0
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| 15 | *
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| 16 | * For matrices, the function is evaluated element wise.
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| 17 | *
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| 18 | * Syntax:
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| 19 | *
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| 20 | * math.sign(x)
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| 21 | *
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| 22 | * Examples:
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| 23 | *
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| 24 | * math.sign(3.5) // returns 1
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| 25 | * math.sign(-4.2) // returns -1
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| 26 | * math.sign(0) // returns 0
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| 27 | *
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| 28 | * math.sign([3, 5, -2, 0, 2]) // returns [1, 1, -1, 0, 1]
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| 29 | *
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| 30 | * See also:
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| 31 | *
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| 32 | * abs
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| 33 | *
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| 34 | * @param {number | BigNumber | Fraction | Complex | Array | Matrix | Unit} x
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| 35 | * The number for which to determine the sign
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| 36 | * @return {number | BigNumber | Fraction | Complex | Array | Matrix | Unit}e
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| 37 | * The sign of `x`
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| 38 | */
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| 39 | const sign = typed(name, {
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| 40 | number: signNumber,
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| 41 |
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| 42 | Complex: function (x) {
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| 43 | return x.im === 0 ? complex(signNumber(x.re)) : x.sign()
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| 44 | },
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| 45 |
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| 46 | BigNumber: function (x) {
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| 47 | return new BigNumber(x.cmp(0))
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| 48 | },
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| 49 |
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| 50 | Fraction: function (x) {
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| 51 | return new Fraction(x.s, 1)
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| 52 | },
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| 53 |
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| 54 | 'Array | Matrix': function (x) {
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| 55 | // deep map collection, skip zeros since sign(0) = 0
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| 56 | return deepMap(x, sign, true)
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| 57 | },
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| 58 |
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| 59 | Unit: function (x) {
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| 60 | return sign(x.value)
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| 61 | }
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| 62 | })
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| 63 |
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| 64 | return sign
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| 65 | })
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