@stdlib/stats-base-nanrange

About stdlib...

We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.

The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.

When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.

To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!

nanrange

Calculate the range of a strided array, ignoring NaN values.

The range is defined as the difference between the maximum and minimum values.

Installation

npm install @stdlib/stats-base-nanrange

Usage

var nanrange = require( '@stdlib/stats-base-nanrange' );

nanrange( N, x, stride )

Computes the range of a strided array x, ignoring NaN values.

var x = [ 1.0, -2.0, NaN, 2.0 ];
var N = x.length;

var v = nanrange( N, x, 1 );
// returns 4.0

The function has the following parameters:

• N: number of indexed elements.
• x: input Array or typed array.
• stride: index increment for x.

The N and stride parameters determine which elements in x are accessed at runtime. For example, to compute the range of every other element in x,

var floor = require( '@stdlib/math-base-special-floor' );

var x = [ 1.0, 2.0, 2.0, -7.0, -2.0, 3.0, 4.0, 2.0, NaN, NaN ];
var N = floor( x.length / 2 );

var v = nanrange( N, x, 2 );
// returns 6.0

Note that indexing is relative to the first index. To introduce an offset, use typed array views.

var Float64Array = require( '@stdlib/array-float64' );
var floor = require( '@stdlib/math-base-special-floor' );

var x0 = new Float64Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, NaN, NaN, 4.0 ] );
var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

var N = floor( x0.length / 2 );

var v = nanrange( N, x1, 2 );
// returns 6.0

nanrange.ndarray( N, x, stride, offset )

Computes the range of a strided array, ignoring NaN values and using alternative indexing semantics.

var x = [ 1.0, -2.0, NaN, 2.0 ];
var N = x.length;

var v = nanrange.ndarray( N, x, 1, 0 );
// returns 4.0

The function has the following additional parameters:

• offset: starting index for x.

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 floor = require( '@stdlib/math-base-special-floor' );

var x = [ 2.0, 1.0, 2.0, -2.0, -2.0, NaN, NaN, 2.0, 3.0, 4.0 ];
var N = floor( x.length / 2 );

var v = nanrange.ndarray( N, x, 2, 1 );
// returns 6.0

Notes

• If N <= 0, both functions return NaN.
• Depending on the environment, the typed versions (dnanrange, snanrange, etc.) are likely to be significantly more performant.

Examples

var randu = require( '@stdlib/random-base-randu' );
var round = require( '@stdlib/math-base-special-round' );
var Float64Array = require( '@stdlib/array-float64' );
var nanrange = require( '@stdlib/stats-base-nanrange' );

var x;
var i;

x = new Float64Array( 10 );
for ( i = 0; i < x.length; i++ ) {
    if ( randu() < 0.2 ) {
        x[ i ] = NaN;
    } else {
        x[ i ] = round( (randu()*100.0) - 50.0 );
    }
}
console.log( x );

var v = nanrange( x.length, x, 1 );
console.log( v );

---

See Also

• @stdlib/stats-base/dnanrange: calculate the range of a double-precision floating-point strided array, ignoring NaN values.
• @stdlib/stats-base/nanmax: calculate the maximum value of a strided array, ignoring NaN values.
• @stdlib/stats-base/nanmin: calculate the minimum value of a strided array, ignoring NaN values.
• @stdlib/stats-base/range: calculate the range of a strided array.
• @stdlib/stats-base/snanrange: calculate the range of a single-precision floating-point strided array, ignoring NaN values.

---

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.