Re: compare similarity between two lines.

what do you mean by similarity?

in 2D space, points describing lines wit the same slope are co-linear.

in N-space, I think you can research something called the "dot" or
inner product. and from that you can determine if lines are parallel or
orthogonal.

the "cross" or outer product can be used to determine the same thing,
since i believe the magnitude of the cross product will provide the
area between the parallelogram formed by the two lines.

maybe if people knew what you were trying to accomplish, they could
provide more help.

.