README.md

nanminBy

Compute the minimum value of a one-dimensional ndarray via a callback function, ignoring NaN values.

Usage

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

nanminBy( arrays, clbk[, thisArg ] )

Computes the minimum value of a one-dimensional ndarray via a callback function, ignoring NaN values.

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

function clbk( value ) {
    return value * 2.0;
}

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

var v = nanminBy( [ x ], clbk );
// returns -4.0

The function has the following parameters:

• arrays: array-like object containing a one-dimensional input ndarray.
• clbk: callback function.
• thisArg: callback execution context (optional).

The invoked callback is provided three arguments:

• value: current array element.
• idx: current array element index.
• array: input ndarray.

To set the callback execution context, provide a thisArg.

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

function clbk( value ) {
    this.count += 1;
    return value * 2.0;
}

var xbuf = [ 1.0, -2.0, NaN, 2.0 ];
var x = new ndarray( 'generic', xbuf, [ 4 ], [ 1 ], 0, 'row-major' );
var ctx = {
    'count': 0
};

var v = nanminBy( [ x ], clbk, ctx );
// returns -4.0

var count = ctx.count;
// returns 4

Notes

• If provided an empty one-dimensional ndarray, the function returns NaN.
• A provided callback function should return a numeric value.
• If a provided callback function returns NaN, the value is ignored.
• If a provided callback function does not return any value (or equivalently, explicitly returns undefined), the value is ignored.

Examples

var filledarrayBy = require( '@stdlib/array/filled-by' );
var bernoulli = require( '@stdlib/random/base/bernoulli' );
var uniform = require( '@stdlib/random/base/uniform' );
var ndarray = require( '@stdlib/ndarray/base/ctor' );
var ndarray2array = require( '@stdlib/ndarray/to-array' );
var nanminBy = require( '@stdlib/stats/base/ndarray/nanmin-by' );

function rand() {
    if ( bernoulli( 0.2 ) > 0 ) {
        return NaN;
    }
    return uniform( -50.0, 50.0 );
}

function clbk( value ) {
    return value * 2.0;
}

var xbuf = filledarrayBy( 10, 'generic', rand );
var x = new ndarray( 'generic', xbuf, [ xbuf.length ], [ 1 ], 0, 'row-major' );
console.log( ndarray2array( x ) );

var v = nanminBy( [ x ], clbk );
console.log( v );