nanmin

Calculate the minimum value of a strided array, ignoring NaN values.

Installation

npm install @stdlib/stats-base-nanmin

Usage

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

nanmin( N, x, stride )

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

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

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

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 minimum value 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 = nanmin( N, x, 2 );
// returns -2.0

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 = nanmin( N, x1, 2 );
// returns -2.0

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

Computes the minimum value 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 = nanmin.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 minimum value 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 = nanmin.ndarray( N, x, 2, 1 );
// returns -2.0

Notes

• If N <= 0, both functions return NaN.
• Depending on the environment, the typed versions (dnanmin, snanmin, 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 nanmin = require( '@stdlib/stats-base-nanmin' );

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

See Also

• @stdlib/stats-base/dnanmin: calculate the minimum value of a double-precision floating-point strided array, ignoring NaN values.
• @stdlib/stats-base/min: calculate the minimum value of a strided array.
• @stdlib/stats-base/nanmax: calculate the maximum value of a strided array, ignoring NaN values.
• @stdlib/stats-base/snanmin: calculate the minimum value 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.