102 lines
2.1 KiB
JavaScript
102 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 isnan = require( '@stdlib/math/base/assert/is-nan' );
|
||
|
|
|
||
|
|
|
||
|
|
// MAIN //
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Computes the range of a strided array according to a mask.
|
||
|
|
*
|
||
|
|
* @param {PositiveInteger} N - number of indexed elements
|
||
|
|
* @param {NumericArray} x - input array
|
||
|
|
* @param {integer} strideX - `x` stride length
|
||
|
|
* @param {NonNegativeInteger} offsetX - `x` starting index
|
||
|
|
* @param {NumericArray} mask - mask array
|
||
|
|
* @param {integer} strideMask - `mask` stride length
|
||
|
|
* @param {NonNegativeInteger} offsetMask - `mask` starting index
|
||
|
|
* @returns {number} range
|
||
|
|
*
|
||
|
|
* @example
|
||
|
|
* var floor = require( '@stdlib/math/base/special/floor' );
|
||
|
|
*
|
||
|
|
* var x = [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0, 5.0, 6.0 ];
|
||
|
|
* var mask = [ 0, 0, 0, 0, 0, 0, 0, 0, 1, 1 ];
|
||
|
|
* var N = floor( x.length / 2 );
|
||
|
|
*
|
||
|
|
* var v = mskrange( N, x, 2, 1, mask, 2, 1 );
|
||
|
|
* // returns 6.0
|
||
|
|
*/
|
||
|
|
function mskrange( N, x, strideX, offsetX, mask, strideMask, offsetMask ) {
|
||
|
|
var max;
|
||
|
|
var min;
|
||
|
|
var ix;
|
||
|
|
var im;
|
||
|
|
var v;
|
||
|
|
var i;
|
||
|
|
|
||
|
|
if ( N <= 0 ) {
|
||
|
|
return NaN;
|
||
|
|
}
|
||
|
|
ix = offsetX;
|
||
|
|
im = offsetMask;
|
||
|
|
for ( i = 0; i < N; i++ ) {
|
||
|
|
if ( mask[ im ] === 0 ) {
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
ix += strideX;
|
||
|
|
im += strideMask;
|
||
|
|
}
|
||
|
|
if ( i === N ) {
|
||
|
|
return NaN;
|
||
|
|
}
|
||
|
|
min = x[ ix ];
|
||
|
|
if ( isnan( min ) ) {
|
||
|
|
return min;
|
||
|
|
}
|
||
|
|
max = min;
|
||
|
|
i += 1;
|
||
|
|
for ( i; i < N; i++ ) {
|
||
|
|
ix += strideX;
|
||
|
|
im += strideMask;
|
||
|
|
if ( mask[ im ] ) {
|
||
|
|
continue;
|
||
|
|
}
|
||
|
|
v = x[ ix ];
|
||
|
|
if ( isnan( v ) ) {
|
||
|
|
return v;
|
||
|
|
}
|
||
|
|
if ( v < min ) {
|
||
|
|
min = v;
|
||
|
|
} else if ( v > max ) {
|
||
|
|
max = v;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return max - min;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
// EXPORTS //
|
||
|
|
|
||
|
|
module.exports = mskrange;
|