README.md

smskmax

Calculate the maximum value of a one-dimensional single-precision floating-point ndarray according to a mask.

Usage

var smskmax = require( '@stdlib/stats/base/ndarray/smskmax' );

smskmax( arrays )

Computes the maximum value of a one-dimensional single-precision floating-point ndarray according to a mask.

var Float32Array = require( '@stdlib/array/float32' );
var Uint8Array = require( '@stdlib/array/uint8' );
var ndarray = require( '@stdlib/ndarray/base/ctor' );

var xbuf = new Float32Array( [ 1.0, -2.0, 4.0, 2.0 ] );
var x = new ndarray( 'float32', xbuf, [ 4 ], [ 1 ], 0, 'row-major' );

var maskbuf = new Uint8Array( [ 0, 0, 1, 0 ] );
var mask = new ndarray( 'uint8', maskbuf, [ 4 ], [ 1 ], 0, 'row-major' );

var v = smskmax( [ x, mask ] );
// returns 2.0

The function has the following parameters:

• arrays: array-like object containing an input ndarray and a mask ndarray.

If a mask array element is 0, the corresponding element in the input ndarray is considered valid and included in computation. If a mask array element is 1, the corresponding element in the input ndarray is considered invalid/missing and excluded from computation.

Notes

• If provided an empty ndarray or a mask with all elements set to 1, the function returns NaN.

Examples

var uniform = require( '@stdlib/random/array/uniform' );
var bernoulli = require( '@stdlib/random/array/bernoulli' );
var ndarray = require( '@stdlib/ndarray/base/ctor' );
var ndarray2array = require( '@stdlib/ndarray/to-array' );
var smskmax = require( '@stdlib/stats/base/ndarray/smskmax' );

var xbuf = uniform( 10, -50.0, 50.0, {
    'dtype': 'float32'
});
var x = new ndarray( 'float32', xbuf, [ xbuf.length ], [ 1 ], 0, 'row-major' );
console.log( ndarray2array( x ) );

var maskbuf = bernoulli( xbuf.length, 0.2, {
    'dtype': 'uint8'
});
var mask = new ndarray( 'uint8', maskbuf, [ maskbuf.length ], [ 1 ], 0, 'row-major' );
console.log( ndarray2array( mask ) );

var v = smskmax( [ x, mask ] );
console.log( v );