85 lines
2.1 KiB
JavaScript
85 lines
2.1 KiB
JavaScript
|
/**
|
||
|
|
* @license Apache-2.0
|
||
|
|
*
|
||
|
|
* Copyright (c) 2020 The Stdlib Authors.
|
||
|
|
*
|
||
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
||
|
|
* you may not use this file except in compliance with the License.
|
||
|
|
* You may obtain a copy of the License at
|
||
|
|
*
|
||
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
||
|
|
*
|
||
|
|
* Unless required by applicable law or agreed to in writing, software
|
||
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
||
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||
|
|
* See the License for the specific language governing permissions and
|
||
|
|
* limitations under the License.
|
||
|
|
*/
|
||
|
|
|
||
|
|
'use strict';
|
||
|
|
|
||
|
|
// MODULES //
|
||
|
|
|
||
|
|
var float64ToFloat32 = require( '@stdlib/number/float64/base/to-float32' );
|
||
|
|
var isPositiveZerof = require( '@stdlib/math/base/assert/is-positive-zerof' );
|
||
|
|
var isNegativeZerof = require( '@stdlib/math/base/assert/is-negative-zerof' );
|
||
|
|
var isnanf = require( '@stdlib/math/base/assert/is-nanf' );
|
||
|
|
|
||
|
|
|
||
|
|
// MAIN //
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Computes the mid-range of a single-precision floating-point strided array.
|
||
|
|
*
|
||
|
|
* @param {PositiveInteger} N - number of indexed elements
|
||
|
|
* @param {Float32Array} x - input array
|
||
|
|
* @param {integer} stride - stride length
|
||
|
|
* @param {NonNegativeInteger} offset - starting index
|
||
|
|
* @returns {number} mid-range
|
||
|
|
*
|
||
|
|
* @example
|
||
|
|
* var Float32Array = require( '@stdlib/array/float32' );
|
||
|
|
* var floor = require( '@stdlib/math/base/special/floor' );
|
||
|
|
*
|
||
|
|
* var x = new Float32Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ] );
|
||
|
|
* var N = floor( x.length / 2 );
|
||
|
|
*
|
||
|
|
* var v = smidrange( N, x, 2, 1 );
|
||
|
|
* // returns 1.0
|
||
|
|
*/
|
||
|
|
function smidrange( N, x, stride, offset ) {
|
||
|
|
var max;
|
||
|
|
var min;
|
||
|
|
var ix;
|
||
|
|
var v;
|
||
|
|
var i;
|
||
|
|
|
||
|
|
if ( N <= 0 ) {
|
||
|
|
return NaN;
|
||
|
|
}
|
||
|
|
if ( N === 1 || stride === 0 ) {
|
||
|
|
return x[ offset ];
|
||
|
|
}
|
||
|
|
ix = offset;
|
||
|
|
min = x[ ix ];
|
||
|
|
max = min;
|
||
|
|
for ( i = 1; i < N; i++ ) {
|
||
|
|
ix += stride;
|
||
|
|
v = x[ ix ];
|
||
|
|
if ( isnanf( v ) ) {
|
||
|
|
return v;
|
||
|
|
}
|
||
|
|
if ( v < min || ( v === min && isNegativeZerof( v ) ) ) {
|
||
|
|
min = v;
|
||
|
|
} else if ( v > max || ( v === max && isPositiveZerof( v ) ) ) {
|
||
|
|
max = v;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return float64ToFloat32( float64ToFloat32( max+min ) / 2.0 );
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
// EXPORTS //
|
||
|
|
|
||
|
|
module.exports = smidrange;
|