function dnanmeanpw( N, x, strideX, offsetX ) {
	WORKSPACE[ 0 ] = 0.0;
	WORKSPACE[ 1 ] = 0;
	dnannsumpw( N, x, strideX, offsetX, WORKSPACE, 1, 0 );
	return WORKSPACE[ 0 ] / WORKSPACE[ 1 ];
}
Computes the arithmetic mean of a double-precision floating-point strided array, ignoring `NaN` values and using pairwise summation.

@param {PositiveInteger} N - number of indexed elements
@param {Float64Array} x - input array
@param {integer} strideX - stride length
@param {NonNegativeInteger} offsetX - starting index
@returns {number} arithmetic mean

@example
var Float64Array = require( '@stdlib/array/float64' );

var x = new Float64Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0, NaN, NaN ] );

var v = dnanmeanpw( 5, x, 2, 1 );
// returns 1.25