triangular.js (1176B)
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 abs = require( '@stdlib/math/base/special/abs' ); 24 var isnan = require( '@stdlib/assert/is-nan' ); 25 26 27 // MAIN // 28 29 /** 30 * Computes the triangular kernel for a value. 31 * 32 * @private 33 * @param {number} u - input value 34 * @returns {number} kernel value at u 35 * 36 * @example 37 * var u = 0.2; 38 * var out = triangular( u ); 39 * // returns 0.8 40 */ 41 function triangular( u ) { 42 var absU; 43 if ( isnan( u ) ) { 44 return NaN; 45 } 46 absU = abs( u ); 47 if ( absU > 1.0 ) { 48 return 0.0; 49 } 50 return 1.0 - absU; 51 } 52 53 54 // EXPORTS // 55 56 module.exports = triangular;