Grzegorz S?odkowicz wrote: > In fact, a proper vector in physics has 4 features: point of > application, magnitude, direction and sense.
No -- a vector has the properties "magnitude" and direction. Although not everything that has magnitude and direction is a vector. It's very unusual to have a fixed point of application as a vector's property (at least I haven't seen it so far). That would complicate equality tests. > In case of a vector in two dimensions (a special case, which you > also fail to stress not to mention that you were talking about > space) the magnitude and sense can be described by one number Actually, the "magnitude" and "sense" you use here are redundant. What's the difference between a vector with magnitude "1" and sense "-", and magnitude "-1" and sense "+"? > and the direction as another. Represent the direction as one number? Only in a one-dimensional space. Regards, Björn -- BOFH excuse #441: Hash table has woodworm -- http://mail.python.org/mailman/listinfo/python-list
