100 lines
1.9 KiB
JavaScript
100 lines
1.9 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 abs = require( '@stdlib/math/base/special/abs' );
|
|
|
|
|
|
// MAIN //
|
|
|
|
/**
|
|
* Computes the cumulative maximum absolute value of a strided array.
|
|
*
|
|
* @param {PositiveInteger} N - number of indexed elements
|
|
* @param {NumericArray} x - input array
|
|
* @param {integer} strideX - `x` stride length
|
|
* @param {NumericArray} y - output array
|
|
* @param {integer} strideY - `y` stride length
|
|
* @returns {NumericArray} output array
|
|
*
|
|
* @example
|
|
* var x = [ 1.0, -2.0, 2.0 ];
|
|
* var y = [ 0.0, 0.0, 0.0 ];
|
|
* var N = x.length;
|
|
*
|
|
* var v = cumaxabs( N, x, 1, y, 1 );
|
|
* // returns [ 1.0, 2.0, 2.0 ]
|
|
*/
|
|
function cumaxabs( N, x, strideX, y, strideY ) {
|
|
var max;
|
|
var ix;
|
|
var iy;
|
|
var v;
|
|
var i;
|
|
|
|
if ( N <= 0 ) {
|
|
return y;
|
|
}
|
|
if ( strideX < 0 ) {
|
|
ix = (1-N) * strideX;
|
|
} else {
|
|
ix = 0;
|
|
}
|
|
if ( strideY < 0 ) {
|
|
iy = (1-N) * strideY;
|
|
} else {
|
|
iy = 0;
|
|
}
|
|
max = abs( x[ ix ] );
|
|
y[ iy ] = max;
|
|
|
|
iy += strideY;
|
|
i = 1;
|
|
if ( isnan( max ) === false ) {
|
|
for ( i; i < N; i++ ) {
|
|
ix += strideX;
|
|
v = abs( x[ ix ] );
|
|
if ( isnan( v ) ) {
|
|
max = v;
|
|
break;
|
|
}
|
|
if ( v > max ) {
|
|
max = v;
|
|
}
|
|
y[ iy ] = max;
|
|
iy += strideY;
|
|
}
|
|
}
|
|
if ( isnan( max ) ) {
|
|
for ( i; i < N; i++ ) {
|
|
y[ iy ] = max;
|
|
iy += strideY;
|
|
}
|
|
}
|
|
return y;
|
|
}
|
|
|
|
|
|
// EXPORTS //
|
|
|
|
module.exports = cumaxabs;
|