time-to-botec/squiggle/node_modules/@stdlib/stats/base/cumaxabs/lib/ndarray.js

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/**
* @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 {NonNegativeInteger} offsetX - starting index for `x`
* @param {NumericArray} y - output array
* @param {integer} strideY - `y` stride length
* @param {NonNegativeInteger} offsetY - starting index for `y`
* @returns {NumericArray} output array
*
* @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 ];
* var y = [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ];
* var N = floor( x.length / 2 );
*
* var v = cumaxabs( N, x, 2, 1, y, 1, 0 );
* // returns [ 1.0, 2.0, 2.0, 4.0, 0.0, 0.0, 0.0, 0.0 ]
*/
function cumaxabs( N, x, strideX, offsetX, y, strideY, offsetY ) {
var max;
var ix;
var iy;
var v;
var i;
if ( N <= 0 ) {
return y;
}
ix = offsetX;
iy = offsetY;
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;