function Ellipsoid(x, y, z) {
  this._radii = undefined;
  this._radiiSquared = undefined;
  this._radiiToTheFourth = undefined;
  this._oneOverRadii = undefined;
  this._oneOverRadiiSquared = undefined;
  this._minimumRadius = undefined;
  this._maximumRadius = undefined;
  this._centerToleranceSquared = undefined;
  this._squaredXOverSquaredZ = undefined;

  initialize(this, x, y, z);
}
A quadratic surface defined in Cartesian coordinates by the equation
<code>(x / a)^2 + (y / b)^2 + (z / c)^2 = 1</code>.  Primarily used
by Cesium to represent the shape of planetary bodies.

Rather than constructing this object directly, one of the provided
constants is normally used.
@alias Ellipsoid
@constructor

@param {number} [x=0] The radius in the x direction.
@param {number} [y=0] The radius in the y direction.
@param {number} [z=0] The radius in the z direction.

@exception {DeveloperError} All radii components must be greater than or equal to zero.

@see Ellipsoid.fromCartesian3
@see Ellipsoid.WGS84
@see Ellipsoid.UNIT_SPHERE