Test two numbers for approximate equality.

Input parameters:

1. A → First number for similarity comparison.
2. B → Second number for similarity comparison.
3. Dt → Allowed discrete steps between numbers.
4. Rt → Allowed relative distance between numbers as a factor of the biggest number.

Output parameters:

1. Cs → True if the values are similar within either the relative or the discrete thresholds. QQ
2. Ds → True if the values are similar within the discrete threshold. QQ
3. Rs → True if the values are similar within the relative threshold. QQ