coefficients.js (1344B)
1 /** 2 * @license Apache-2.0 3 * 4 * Copyright (c) 2018 The Stdlib Authors. 5 * 6 * Licensed under the Apache License, Version 2.0 (the "License"); 7 * you may not use this file except in compliance with the License. 8 * You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 19 'use strict'; 20 21 // MODULES // 22 23 var binomcoef = require( './../../../../base/special/binomcoef' ); 24 var cache = require( './cache.js' ); 25 26 27 // MAIN // 28 29 /** 30 * Computes polynomial coefficients. 31 * 32 * @private 33 * @param {NonNegativeInteger} n - Fibonacci polynomial for which to compute coefficients 34 * @returns {NonNegativeIntegerArray} polynomial coefficients 35 */ 36 function coefficients( n ) { 37 var coefs; 38 var i; 39 40 coefs = cache[ n ]; 41 if ( coefs === void 0 ) { 42 coefs = []; 43 for ( i = 0; i < n; i++ ) { 44 coefs.push( 0.0 ); 45 } 46 for ( i = n-1; i >= 0; i -= 2 ) { 47 coefs[ i ] = binomcoef( (n+i-1)/2, i ); 48 } 49 // Memoize the coefficients: 50 cache[ n ] = coefs; 51 } 52 return coefs; 53 } 54 55 56 // EXPORTS // 57 58 module.exports = coefficients;