Classify the relationship between two vectors.

Input parameters:

1. Va → First vector for relationship.
2. Vb → Second vector for relationship.
3. An → Angle threshold for classification.

Output parameters:

1. P+ → True if the vectors are parallel within the angle tolerance. QQ
2. P- → True if the vectors are anti-parallel within the angle tolerance. QQ
3. P0 → True if the vectors are perpendicular within the angle tolerance. QQ