1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
|
/**
* @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 sorted strided array.
*
* @param {PositiveInteger} N - number of indexed elements
* @param {NumericArray} x - sorted input array
* @param {integer} stride - stride length
* @param {NonNegativeInteger} offset - starting index
* @returns {number} maximum value
*
* @example
* var floor = require( '@stdlib/math/base/special/floor' );
*
* var x = [ 2.0, -3.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ];
* var N = floor( x.length / 2 );
*
* var v = maxsorted( N, x, 2, 1 );
* // returns 4.0
*/
function maxsorted( N, x, stride, offset ) {
var v1;
var v2;
if ( N <= 0 ) {
return NaN;
}
if ( N === 1 || stride === 0 ) {
return x[ 0 ];
}
v1 = x[ offset ];
v2 = x[ offset + ((N-1)*stride) ];
if ( isnan( v1 ) || isnan( v2 ) ) {
return NaN;
}
if ( v1 === v2 ) {
if ( isPositiveZero( v1 ) || isPositiveZero( v2 ) ) {
return 0.0;
}
return v1;
}
if ( v1 > v2 ) {
return v1;
}
return v2;
}
// EXPORTS //
module.exports = maxsorted;
|
