README.md

dnanmeanpw

Compute the arithmetic mean of a one-dimensional double-precision floating-point ndarray, ignoring NaN values and using pairwise summation.

The arithmetic mean is defined as

$$\mu = \frac{1}{n} \sum_{i=0}^{n-1} x_i$$

Usage

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

dnanmeanpw( arrays )

Computes the arithmetic mean of a one-dimensional double-precision floating-point ndarray, ignoring NaN values and using pairwise summation.

var Float64Array = require( '@stdlib/array/float64' );
var ndarray = require( '@stdlib/ndarray/base/ctor' );

var xbuf = new Float64Array( [ 1.0, -2.0, NaN, 2.0 ] );
var x = new ndarray( 'float64', xbuf, [ 4 ], [ 1 ], 0, 'row-major' );

var v = dnanmeanpw( [ x ] );
// returns 0.3333333333333333

The function has the following parameters:

• arrays: array-like object containing a one-dimensional input ndarray.

Notes

• If provided an empty one-dimensional ndarray, the function returns NaN.

Examples

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

function rand() {
    if ( bernoulli( 0.8 ) < 1 ) {
        return NaN;
    }
    return uniform( -50.0, 50.0 );
}

var xbuf = filledarrayBy( 10, 'float64', rand );
var x = new ndarray( 'float64', xbuf, [ xbuf.length ], [ 1 ], 0, 'row-major' );
console.log( ndarray2array( x ) );

var v = dnanmeanpw( [ x ] );
console.log( v );

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References

• Higham, Nicholas J. 1993. "The Accuracy of Floating Point Summation." SIAM Journal on Scientific Computing 14 (4): 783–99. doi:10.1137/0914050.