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smskrange
Calculate the range of a single-precision floating-point strided array according to a mask.
The range is defined as the difference between the maximum and minimum values.
Installation
npm install @stdlib/stats-base-smskrange
Usage
var smskrange = require( '@stdlib/stats-base-smskrange' );
smskrange( N, x, strideX, mask, strideMask )
Computes the range of a single-precision floating-point strided array x
according to a mask
.
var Float32Array = require( '@stdlib/array-float32' );
var Uint8Array = require( '@stdlib/array-uint8' );
var x = new Float32Array( [ 1.0, -2.0, 4.0, 2.0 ] );
var mask = new Uint8Array( [ 0, 0, 1, 0 ] );
var v = smskrange( x.length, x, 1, mask, 1 );
// returns 4.0
The function has the following parameters:
- N: number of indexed elements.
-
x: input
Float32Array
. -
strideX: index increment for
x
. -
mask: mask
Uint8Array
. If amask
array element is0
, the corresponding element inx
is considered valid and included in computation. If amask
array element is1
, the corresponding element inx
is considered invalid/missing and excluded from computation. -
strideMask: index increment for
mask
.
The N
and stride
parameters determine which elements are accessed at runtime. For example, to compute the range of every other element in x
,
var Float32Array = require( '@stdlib/array-float32' );
var Uint8Array = require( '@stdlib/array-uint8' );
var floor = require( '@stdlib/math-base-special-floor' );
var x = new Float32Array( [ 1.0, 2.0, -7.0, -2.0, 4.0, 3.0, 5.0, 6.0 ] );
var mask = new Uint8Array( [ 0, 0, 0, 0, 0, 0, 1, 1 ] );
var N = floor( x.length / 2 );
var v = smskrange( N, x, 2, mask, 2 );
// returns 11.0
Note that indexing is relative to the first index. To introduce offsets, use typed array
views.
var Float32Array = require( '@stdlib/array-float32' );
var Uint8Array = require( '@stdlib/array-uint8' );
var floor = require( '@stdlib/math-base-special-floor' );
var x0 = new Float32Array( [ 2.0, 1.0, -2.0, -2.0, 3.0, 4.0, 5.0, 6.0 ] );
var x1 = new Float32Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
var mask0 = new Uint8Array( [ 0, 0, 0, 0, 0, 0, 1, 1 ] );
var mask1 = new Uint8Array( mask0.buffer, mask0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
var N = floor( x0.length / 2 );
var v = smskrange( N, x1, 2, mask1, 2 );
// returns 6.0
smskrange.ndarray( N, x, strideX, offsetX, mask, strideMask, offsetMask )
Computes the range of a single-precision floating-point strided array according to a mask
and using alternative indexing semantics.
var Float32Array = require( '@stdlib/array-float32' );
var Uint8Array = require( '@stdlib/array-uint8' );
var x = new Float32Array( [ 1.0, -2.0, 4.0, 2.0 ] );
var mask = new Uint8Array( [ 0, 0, 1, 0 ] );
var v = smskrange.ndarray( x.length, x, 1, 0, mask, 1, 0 );
// returns 4.0
The function has the following additional parameters:
-
offsetX: starting index for
x
. -
offsetMask: starting index for
mask
.
While typed array
views mandate a view offset based on the underlying buffer
, the offset
parameter supports indexing semantics based on a starting index. For example, to calculate the range for every other value in x
starting from the second value
var Float32Array = require( '@stdlib/array-float32' );
var Uint8Array = require( '@stdlib/array-uint8' );
var floor = require( '@stdlib/math-base-special-floor' );
var x = new Float32Array( [ 2.0, 1.0, -2.0, -2.0, 3.0, 4.0, 5.0, 6.0 ] );
var mask = new Uint8Array( [ 0, 0, 0, 0, 0, 0, 1, 1 ] );
var N = floor( x.length / 2 );
var v = smskrange.ndarray( N, x, 2, 1, mask, 2, 1 );
// returns 6.0
Notes
- If
N <= 0
, both functions returnNaN
.
Examples
var randu = require( '@stdlib/random-base-randu' );
var round = require( '@stdlib/math-base-special-round' );
var Float32Array = require( '@stdlib/array-float32' );
var Uint8Array = require( '@stdlib/array-uint8' );
var smskrange = require( '@stdlib/stats-base-smskrange' );
var mask;
var x;
var i;
x = new Float32Array( 10 );
mask = new Uint8Array( x.length );
for ( i = 0; i < x.length; i++ ) {
if ( randu() < 0.2 ) {
mask[ i ] = 1;
} else {
mask[ i ] = 0;
}
x[ i ] = round( (randu()*100.0) - 50.0 );
}
console.log( x );
console.log( mask );
var v = smskrange( x.length, x, 1, mask, 1 );
console.log( v );
See Also
-
@stdlib/stats-base/dmskrange
: calculate the range of a double-precision floating-point strided array according to a mask. -
@stdlib/stats-base/mskrange
: calculate the range of a strided array according to a mask. -
@stdlib/stats-base/smskmax
: calculate the maximum value of a single-precision floating-point strided array according to a mask. -
@stdlib/stats-base/smskmin
: calculate the minimum value of a single-precision floating-point strided array according to a mask. -
@stdlib/stats-base/snanrange
: calculate the range of a single-precision floating-point strided array, ignoring NaN values. -
@stdlib/stats-base/srange
: calculate the range of a single-precision floating-point strided array.
Notice
This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.
Community
License
See LICENSE.
Copyright
Copyright © 2016-2024. The Stdlib Authors.