V - Algorithms
The two algorithms available for V fields are:
- On/OFF
- Proportional
Note: a value of 0 means an unknown value
On/OFF:
- When comparing data, states A, B, …, N are considered as different (Sim = 0). Identical states have a similarity = 1.
- V algorithm produces comparisons that are symmetrical Similarity(a, b) = Similarity(b, a).
- if values are identical: sim = 1.0, even if one is unknown
- else if one of the values is 0: sim = Not a Number
Proportional:
- if algorithm = Proportional, sim = 1.0 - difference between the two values divided by the (number of possible values - 2)
Ex. with 6 possible values (0 = unknown, 1, 2, 3, 4 and 5):
sim = 1.0 - abs(5 - 5) / 4.0 = 1.0
sim = 1.0 - abs(5 - 4) / 4.0 = 0.75
sim = 1.0 - abs(5 - 3) / 4.0 = 0.5
sim = 1.0 - abs(5 - 2) / 4.0 = 0.25
sim = 1.0 - abs(5 - 1) / 4.0 = 0.0
note that comparing (5 - 4) or comparing (2-1) give the same result:
sim = 1.0 - abs(5 - 4) / 4.0 = 0.75
sim = 1.0 - abs(2 - 1) / 4.0 = 0.75
Suitable for identification and classification purposes.