90 lines
1.7 KiB
JavaScript
90 lines
1.7 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' );
|
||
|
|
var isPositiveZero = require( '@stdlib/math/base/assert/is-positive-zero' );
|
||
|
|
|
||
|
|
|
||
|
|
// MAIN //
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Computes the maximum value of a strided array, ignoring `NaN` values.
|
||
|
|
*
|
||
|
|
* @param {PositiveInteger} N - number of indexed elements
|
||
|
|
* @param {NumericArray} x - input array
|
||
|
|
* @param {integer} stride - stride length
|
||
|
|
* @returns {number} maximum value
|
||
|
|
*
|
||
|
|
* @example
|
||
|
|
* var x = [ 1.0, -2.0, NaN, 2.0 ];
|
||
|
|
* var N = x.length;
|
||
|
|
*
|
||
|
|
* var v = nanmax( N, x, 1 );
|
||
|
|
* // returns 2.0
|
||
|
|
*/
|
||
|
|
function nanmax( N, x, stride ) {
|
||
|
|
var max;
|
||
|
|
var ix;
|
||
|
|
var v;
|
||
|
|
var i;
|
||
|
|
|
||
|
|
if ( N <= 0 ) {
|
||
|
|
return NaN;
|
||
|
|
}
|
||
|
|
if ( N === 1 || stride === 0 ) {
|
||
|
|
return x[ 0 ];
|
||
|
|
}
|
||
|
|
if ( stride < 0 ) {
|
||
|
|
ix = (1-N) * stride;
|
||
|
|
} else {
|
||
|
|
ix = 0;
|
||
|
|
}
|
||
|
|
for ( i = 0; i < N; i++ ) {
|
||
|
|
v = x[ ix ];
|
||
|
|
if ( v === v ) {
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
ix += stride;
|
||
|
|
}
|
||
|
|
if ( i === N ) {
|
||
|
|
return NaN;
|
||
|
|
}
|
||
|
|
max = v;
|
||
|
|
i += 1;
|
||
|
|
for ( i; i < N; i++ ) {
|
||
|
|
ix += stride;
|
||
|
|
v = x[ ix ];
|
||
|
|
if ( isnan( v ) ) {
|
||
|
|
continue;
|
||
|
|
}
|
||
|
|
if ( v > max || ( v === max && isPositiveZero( v ) ) ) {
|
||
|
|
max = v;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return max;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
// EXPORTS //
|
||
|
|
|
||
|
|
module.exports = nanmax;
|