time-to-botec

Benchmark sampling in different programming languages
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ndarray.js (2034B)

      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 isPositiveZero = require( '@stdlib/math/base/assert/is-positive-zero' );
     24 var isNegativeZero = require( '@stdlib/math/base/assert/is-negative-zero' );
     25 var isnan = require( '@stdlib/math/base/assert/is-nan' );
     26 
     27 
     28 // MAIN //
     29 
     30 /**
     31 * Computes the mid-range of a double-precision floating-point strided array.
     32 *
     33 * @param {PositiveInteger} N - number of indexed elements
     34 * @param {Float64Array} x - input array
     35 * @param {integer} stride - stride length
     36 * @param {NonNegativeInteger} offset - starting index
     37 * @returns {number} mid-range
     38 *
     39 * @example
     40 * var Float64Array = require( '@stdlib/array/float64' );
     41 * var floor = require( '@stdlib/math/base/special/floor' );
     42 *
     43 * var x = new Float64Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ] );
     44 * var N = floor( x.length / 2 );
     45 *
     46 * var v = dmidrange( N, x, 2, 1 );
     47 * // returns 1.0
     48 */
     49 function dmidrange( N, x, stride, offset ) {
     50 	var max;
     51 	var min;
     52 	var ix;
     53 	var v;
     54 	var i;
     55 
     56 	if ( N <= 0 ) {
     57 		return NaN;
     58 	}
     59 	if ( N === 1 || stride === 0 ) {
     60 		return x[ offset ];
     61 	}
     62 	ix = offset;
     63 	min = x[ ix ];
     64 	max = min;
     65 	for ( i = 1; i < N; i++ ) {
     66 		ix += stride;
     67 		v = x[ ix ];
     68 		if ( isnan( v ) ) {
     69 			return v;
     70 		}
     71 		if ( v < min || ( v === min && isNegativeZero( v ) ) ) {
     72 			min = v;
     73 		} else if ( v > max || ( v === max && isPositiveZero( v ) ) ) {
     74 			max = v;
     75 		}
     76 	}
     77 	return ( max+min ) / 2.0;
     78 }
     79 
     80 
     81 // EXPORTS //
     82 
     83 module.exports = dmidrange;