time-to-botec

Benchmark sampling in different programming languages
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snanmaxabs.js (1875B)

      1 /**
      2 * @license Apache-2.0
      3 *
      4 * Copyright (c) 2020 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 isnanf = require( '@stdlib/math/base/assert/is-nanf' );
     24 var abs = require( '@stdlib/math/base/special/abs' );
     25 
     26 
     27 // MAIN //
     28 
     29 /**
     30 * Computes the maximum absolute value of a single-precision floating-point strided array, ignoring `NaN` values.
     31 *
     32 * @param {PositiveInteger} N - number of indexed elements
     33 * @param {Float32Array} x - input array
     34 * @param {integer} stride - stride length
     35 * @returns {number} maximum absolute value
     36 *
     37 * @example
     38 * var Float32Array = require( '@stdlib/array/float32' );
     39 *
     40 * var x = new Float32Array( [ 1.0, -2.0, NaN, 2.0 ] );
     41 * var N = x.length;
     42 *
     43 * var v = snanmaxabs( N, x, 1 );
     44 * // returns 2.0
     45 */
     46 function snanmaxabs( N, x, stride ) {
     47 	var max;
     48 	var ix;
     49 	var v;
     50 	var i;
     51 
     52 	if ( N <= 0 ) {
     53 		return NaN;
     54 	}
     55 	if ( N === 1 || stride === 0 ) {
     56 		return abs( x[ 0 ] );
     57 	}
     58 	if ( stride < 0 ) {
     59 		ix = (1-N) * stride;
     60 	} else {
     61 		ix = 0;
     62 	}
     63 	for ( i = 0; i < N; i++ ) {
     64 		v = x[ ix ];
     65 		if ( v === v ) {
     66 			break;
     67 		}
     68 		ix += stride;
     69 	}
     70 	if ( i === N ) {
     71 		return NaN;
     72 	}
     73 	max = abs( v );
     74 	i += 1;
     75 	for ( i; i < N; i++ ) {
     76 		ix += stride;
     77 		v = abs( x[ ix ] );
     78 		if ( isnanf( v ) ) {
     79 			continue;
     80 		}
     81 		if ( v > max ) {
     82 			max = v;
     83 		}
     84 	}
     85 	return max;
     86 }
     87 
     88 
     89 // EXPORTS //
     90 
     91 module.exports = snanmaxabs;