1 | import { deepMap } from '../../utils/collection'
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2 | import { factory } from '../../utils/factory'
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3 |
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4 | const name = 'factorial'
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5 | const dependencies = ['typed', 'gamma']
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6 |
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7 | export const createFactorial = /* #__PURE__ */ factory(name, dependencies, ({ typed, gamma }) => {
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8 | /**
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9 | * Compute the factorial of a value
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10 | *
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11 | * Factorial only supports an integer value as argument.
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12 | * For matrices, the function is evaluated element wise.
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13 | *
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14 | * Syntax:
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15 | *
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16 | * math.factorial(n)
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17 | *
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18 | * Examples:
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19 | *
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20 | * math.factorial(5) // returns 120
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21 | * math.factorial(3) // returns 6
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22 | *
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23 | * See also:
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24 | *
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25 | * combinations, combinationsWithRep, gamma, permutations
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26 | *
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27 | * @param {number | BigNumber | Array | Matrix} n An integer number
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28 | * @return {number | BigNumber | Array | Matrix} The factorial of `n`
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29 | */
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30 | const factorial = typed(name, {
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31 | number: function (n) {
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32 | if (n < 0) {
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33 | throw new Error('Value must be non-negative')
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34 | }
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35 |
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36 | return gamma(n + 1)
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37 | },
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38 |
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39 | BigNumber: function (n) {
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40 | if (n.isNegative()) {
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41 | throw new Error('Value must be non-negative')
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42 | }
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43 |
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44 | return gamma(n.plus(1))
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45 | },
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46 |
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47 | 'Array | Matrix': function (n) {
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48 | return deepMap(n, factorial)
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49 | }
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50 | })
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51 |
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52 | return factorial
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53 | })
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