time-to-botec

Benchmark sampling in different programming languages
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ndarray.js (2244B)

      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 isnan = require( '@stdlib/math/base/assert/is-nan' );
     24 var isPositiveZero = require( '@stdlib/math/base/assert/is-positive-zero' );
     25 
     26 
     27 // MAIN //
     28 
     29 /**
     30 * Computes the maximum value of a strided array according to a mask.
     31 *
     32 * @param {PositiveInteger} N - number of indexed elements
     33 * @param {NumericArray} x - input array
     34 * @param {integer} strideX - `x` stride length
     35 * @param {NonNegativeInteger} offsetX - `x` starting index
     36 * @param {NumericArray} mask - mask array
     37 * @param {integer} strideMask - `mask` stride length
     38 * @param {NonNegativeInteger} offsetMask - `mask` starting index
     39 * @returns {number} maximum value
     40 *
     41 * @example
     42 * var floor = require( '@stdlib/math/base/special/floor' );
     43 *
     44 * var x = [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0, 5.0, 6.0 ];
     45 * var mask = [ 0, 0, 0, 0, 0, 0, 0, 0, 1, 1 ];
     46 * var N = floor( x.length / 2 );
     47 *
     48 * var v = mskmax( N, x, 2, 1, mask, 2, 1 );
     49 * // returns 4.0
     50 */
     51 function mskmax( N, x, strideX, offsetX, mask, strideMask, offsetMask ) {
     52 	var max;
     53 	var ix;
     54 	var im;
     55 	var v;
     56 	var i;
     57 
     58 	if ( N <= 0 ) {
     59 		return NaN;
     60 	}
     61 	ix = offsetX;
     62 	im = offsetMask;
     63 	for ( i = 0; i < N; i++ ) {
     64 		if ( mask[ im ] === 0 ) {
     65 			break;
     66 		}
     67 		ix += strideX;
     68 		im += strideMask;
     69 	}
     70 	if ( i === N ) {
     71 		return NaN;
     72 	}
     73 	max = x[ ix ];
     74 	if ( isnan( max ) ) {
     75 		return max;
     76 	}
     77 	i += 1;
     78 	for ( i; i < N; i++ ) {
     79 		ix += strideX;
     80 		im += strideMask;
     81 		if ( mask[ im ] ) {
     82 			continue;
     83 		}
     84 		v = x[ ix ];
     85 		if ( isnan( v ) ) {
     86 			return v;
     87 		}
     88 		if ( v > max || ( v === max && isPositiveZero( v ) ) ) {
     89 			max = v;
     90 		}
     91 	}
     92 	return max;
     93 }
     94 
     95 
     96 // EXPORTS //
     97 
     98 module.exports = mskmax;