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Ranking
CF-TOPSIS - Complex extension of TOPSIS
Complex outranking/ranking - Complex Fuzzy Set (CFS: amplitude r ∈ [0,1], phase ω ∈ [0,2π])
Ramot, D., Milo, R., Friedman, M., Kandel, A.2002doi:10.1109/91.995119 ↗
Overview
cf-topsis extends TOPSIS to handle Complex uncertainty. All arithmetic operations (normalisation, weighting, distance computation) are performed using Complex Fuzzy Set (CFS: amplitude r ∈ [0,1], phase ω ∈ [0,2π]) algebra. The final scores are defuzzified via real part: r·cos(ω) before ranking.
- Output
- utility, higher is better
- Data
- Complex Intuitionistic Fuzzy, uncertainty tuples complete
- Weights
- Needs a weight source
- Size
- 2+ alternatives, 3-10 criteria works best
- Used for
- Complex Fuzzy MCDM, MAGDM under epistemic uncertainty, expert-driven evaluation with linguistic terms
Look elsewhere when
- •Crisp data sufficient - use base TOPSIS directly (avoid unnecessary uncertainty layer)
- •Aggregation operator (PFWA/PFOWA/etc.) not specified - output ambiguous
Assumptions to verify
- Decision matrix entries are valid Complex Fuzzy numbers/tuples
- Underlying crisp method's compensation assumption holds in uncertain space
- All decision-maker(s) and experts use the same linguistic/uncertainty scale
Edge cases and pitfalls
Value-space violation: ensure all entries satisfy CFS: r(x)·e^{iω(x)} where r ∈ [0,1], ω ∈ [0,2π] before computation.
Defuzzification method affects ranking: real part: r·cos(ω) is the canonical choice but alternatives exist.
Works with
Commonly takes its weights from
How to cite
Ramot, D.; Milo, R.; Friedman, M.; Kandel, A. (2002). Complex fuzzy sets. IEEE Transactions on Fuzzy Systems. https://doi.org/10.1109/91.995119
System ID, as it appears in reports and the API
CF-TOPSIS