52 lines
1.5 KiB
JavaScript
52 lines
1.5 KiB
JavaScript
import { deepForEach } from '../../utils/collection.js';
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import { factory } from '../../utils/factory.js';
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var name = 'multinomial';
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var dependencies = ['typed', 'add', 'divide', 'multiply', 'factorial', 'isInteger', 'isPositive'];
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export var createMultinomial = /* #__PURE__ */factory(name, dependencies, _ref => {
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var {
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typed,
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add,
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divide,
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multiply,
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factorial,
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isInteger,
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isPositive
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} = _ref;
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/**
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* Multinomial Coefficients compute the number of ways of picking a1, a2, ..., ai unordered outcomes from `n` possibilities.
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*
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* multinomial takes one array of integers as an argument.
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* The following condition must be enforced: every ai <= 0
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*
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* Syntax:
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*
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* math.multinomial(a) // a is an array type
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*
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* Examples:
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*
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* math.multinomial([1,2,1]) // returns 12
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*
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* See also:
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*
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* combinations, factorial
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*
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* @param {number[] | BigNumber[]} a Integer numbers of objects in the subset
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* @return {Number | BigNumber} Multinomial coefficient.
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*/
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return typed(name, {
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'Array | Matrix': function ArrayMatrix(a) {
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var sum = 0;
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var denom = 1;
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deepForEach(a, function (ai) {
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if (!isInteger(ai) || !isPositive(ai)) {
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throw new TypeError('Positive integer value expected in function multinomial');
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}
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sum = add(sum, ai);
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denom = multiply(denom, factorial(ai));
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});
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return divide(factorial(sum), denom);
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}
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});
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}); |