@stdlib/stats-base-snanmaxabs

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snanmaxabs

Calculate the maximum absolute value of a single-precision floating-point strided array, ignoring NaN values.

Installation

npm install @stdlib/stats-base-snanmaxabs

Usage

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

snanmaxabs( N, x, stride )

Computes the maximum absolute value of a single-precision floating-point strided array x, ignoring NaN values.

var Float32Array = require( '@stdlib/array-float32' );

var x = new Float32Array( [ 1.0, -2.0, NaN, 2.0 ] );
var N = x.length;

var v = snanmaxabs( N, x, 1 );
// returns 2.0

The function has the following parameters:

• N: number of indexed elements.
• x: input Float32Array.
• stride: index increment for x.

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

var Float32Array = require( '@stdlib/array-float32' );
var floor = require( '@stdlib/math-base-special-floor' );

var x = new Float32Array( [ 1.0, 2.0, -7.0, -2.0, 4.0, 3.0, NaN, NaN ] );
var N = floor( x.length / 2 );

var v = snanmaxabs( N, x, 2 );
// returns 7.0

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

var Float32Array = require( '@stdlib/array-float32' );
var floor = require( '@stdlib/math-base-special-floor' );

var x0 = new Float32Array( [ 2.0, 1.0, -2.0, -2.0, 3.0, 4.0, NaN, NaN ] );
var x1 = new Float32Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

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

var v = snanmaxabs( N, x1, 2 );
// returns 4.0

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

Computes the maximum absolute value of a single-precision floating-point strided array, ignoring NaN values and using alternative indexing semantics.

var Float32Array = require( '@stdlib/array-float32' );

var x = new Float32Array( [ 1.0, -2.0, NaN, 2.0 ] );
var N = x.length;

var v = snanmaxabs.ndarray( N, x, 1, 0 );
// returns 2.0

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 maximum absolute value for every other value in x starting from the second value

var Float32Array = require( '@stdlib/array-float32' );
var floor = require( '@stdlib/math-base-special-floor' );

var x = new Float32Array( [ 2.0, 1.0, -2.0, -2.0, 3.0, 4.0, NaN, NaN ] );
var N = floor( x.length / 2 );

var v = snanmaxabs.ndarray( N, x, 2, 1 );
// returns 4.0

Notes

• If N <= 0, both functions return NaN.

Examples

var randu = require( '@stdlib/random-base-randu' );
var round = require( '@stdlib/math-base-special-round' );
var Float32Array = require( '@stdlib/array-float32' );
var snanmaxabs = require( '@stdlib/stats-base-snanmaxabs' );

var x;
var i;

x = new Float32Array( 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 = snanmaxabs( x.length, x, 1 );
console.log( v );

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See Also

• @stdlib/stats-base/dnanmaxabs: calculate the maximum absolute value of a double-precision floating-point strided array, ignoring NaN values.
• @stdlib/stats-base/nanmaxabs: calculate the maximum absolute value of a strided array, ignoring NaN values.
• @stdlib/stats-base/smaxabs: calculate the maximum absolute value of a single-precision floating-point strided array.
• @stdlib/stats-base/snanmax: calculate the maximum value of a single-precision floating-point strided array, ignoring NaN values.
• @stdlib/stats-base/snanminabs: calculate the minimum absolute value of a single-precision floating-point strided array, ignoring NaN values.

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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

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License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.