Description
Calculate Tversky score and alphaDerivative=-intersection*firstOnly/denominator² from denominator=intersection+alpha*firstOnly+beta*secondOnly.
A similarity term depends on the comparison universe, missing-value policy, treatment of repeated features, and normalization. A score can also have a caller-selected value when its mathematical denominator vanishes. Those conventions matter before interpreting a threshold or comparing methods.
Calculate Tversky score and alphaDerivative=-intersection*firstOnly/denominator² from denominator=intersection+alpha*firstOnly+beta*secondOnly.
When to use this tool
Use Tversky One Sided Penalty Parameter when you need this particular comparison term, normalization, domain condition, or empty-result policy in a larger matching workflow.
How to use the tool and how it works
- Enter intersection, firstOnly, secondOnly, alpha, beta. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read score, alphaDerivative. Use the output convention below.
Calculate Tversky score and alphaDerivative=-intersection*firstOnly/denominator² from denominator=intersection+alpha*firstOnly+beta*secondOnly. Require nonnegative inputs and positive denominator.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| intersection | Intersection | Required. Finite number. |
| firstOnly | First Only | Required. Finite number. |
| secondOnly | Second Only | Required. Finite number. |
| alpha | Alpha | Required. Finite number. |
| beta | Beta | Required. Finite number. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| score | Score | Required. Finite number. |
| alphaDerivative | Alpha Derivative | Required. Finite number. |
{
"input": {
"intersection": 3,
"firstOnly": 2,
"secondOnly": 1,
"alpha": 0.5,
"beta": 1
},
"output": {
"score": 0.6,
"alphaDerivative": -0.24
}
}Limitations and assumptions
- The derivative holds other inputs fixed and is a continuous sensitivity term, not a discrete added-feature effect. No feature counts or penalty choices are inferred.
- The field tables state structural bounds; the mechanics also specify cross-field constraints. Malformed inputs and unsupported domains cause errors. A successful false flag, empty branch value, or zero placeholder has the meaning stated above and is distinct from an input error.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Signed zero is exported as zero.
Alternative or Complementary methods
Compare methods only after aligning feature definitions, missingness, empty policies, multiplicities, and normalizers. Use a complete comparison when the tool returns only one contribution or count check.
References
Similar or alternative tools
- Tversky Parameter Swap Duality
Calculate intersection/(intersection+alpha*leftOnly+beta*rightOnly) and return that value as both forward and reverseWithSwappedWeights.
- Tversky Alpha Beta Swap Gap
Compare swapping the asymmetry weights of one supplied Tversky overlap.