function gnansumors( N, x, strideX, offsetX ) {
	var sum;
	var ix;
	var o;
	var i;

	if ( N <= 0 ) {
		return 0.0;
	}
	o = arraylike2object( x );
	if ( o.accessorProtocol ) {
		return accessors( N, o, strideX, offsetX );
	}
	ix = offsetX;
	if ( strideX === 0 ) {
		if ( isnan( x[ ix ] ) ) {
			return 0.0;
		}
		return N * x[ ix ];
	}
	sum = 0.0;
	for ( i = 0; i < N; i++ ) {
		if ( isnan( x[ ix ] ) === false ) {
			sum += x[ ix ];
		}
		ix += strideX;
	}
	return sum;
}
Computes the sum of strided array elements, ignoring `NaN` values and using ordinary recursive summation.

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

@example
var x = [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ];

var v = gnansumors( 4, x, 2, 1 );
// returns 5.0