function dsumors( N, x, strideX, offsetX ) {
	var sum;
	var ix;
	var m;
	var i;

	if ( N <= 0 ) {
		return 0.0;
	}
	ix = offsetX;
	if ( strideX === 0 ) {
		return N * x[ ix ];
	}
	sum = x[ ix ];
	ix += strideX;

	// If the stride is equal to `1`, use unrolled loops...
	if ( strideX === 1 ) {
		m = (N-1) % M;

		// If we have a remainder, run a clean-up loop...
		if ( m > 0 ) {
			for ( i = 0; i < m; i++ ) {
				sum += x[ ix ];
				ix += strideX;
			}
		}
		if ( N < M ) {
			return sum;
		}
		for ( i = m; i < N-1; i += M ) {
			sum += x[ix] + x[ix+1] + x[ix+2] + x[ix+3] + x[ix+4] + x[ix+5];
			ix += M;
		}
		return sum;
	}
	for ( i = 1; i < N; i++ ) {
		sum += x[ ix ];
		ix += strideX;
	}
	return sum;
}
Computes the sum of double-precision floating-point strided array elements using ordinary recursive 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} sum

@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 ] );

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