function gscal( N, alpha, x, stride ) {
	return ndarray( N, alpha, x, stride, stride2offset( N, stride ) );
}
Multiplies a vector by a scalar constant.

@param {PositiveInteger} N - number of indexed elements
@param {number} alpha - scalar constant
@param {NumericArray} x - input array
@param {PositiveInteger} stride -  stride length
@returns {NumericArray} input array

@example
var x = [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ];

gscal( x.length, 5.0, x, 1 );
// x => [ -10.0, 5.0, 15.0, -25.0, 20.0, 0.0, -5.0, -15.0 ]