Get the length of a 4-dimensional double-precision vector.
@param x The vector's x component @param y The vector's y component @param z The vector's z component @param w The vector's w component
@return the length of the given vector
@author F. Neurath
See Implementation
Get the length of a 4-dimensional double-precision vector.
@param x The vector's x component @param y The vector's y component @param z The vector's z component @param w The vector's w component
@return the length of the given vector
@author F. Neurath