Queried by: validatorssubnet ownersdevelopersanalytics
The Big Picture
Kappa is a Yuma Consensus parameter controlling how validator stake affects their influence. Higher kappa means stake matters more - large validators dominate. Lower kappa reduces stake influence, giving smaller validators more relative power.
Why This Matters
How much does stake matter in consensus? Kappa determines this. It's a fundamental parameter for understanding power dynamics on a subnet.
Example Scenario
Query Kappa(netuid=1) returns the consensus parameter value. Higher values concentrate power in high-stake validators; lower values distribute influence more evenly.
Common Questions
- What's a typical kappa value?
- Varies by subnet design. Check specific subnet documentation for their intended consensus dynamics.
- Can subnet owners change this?
- Depends on governance. Some parameters are adjustable, others fixed. Changing kappa significantly alters network dynamics.
Use Cases
- Understand how stake affects consensus power
- Research Yuma Consensus parameters
- Model emission distributions
- Design subnet incentive mechanisms
- Debug unexpected consensus outcomes
From Chain Metadata
MAP ( netuid ) --> Kappa
Purpose & Usage
Purpose
Tune consensus mechanism - controls how stake affects weight processing.
Common Query Patterns
- Query by netuid
- Research consensus behavior
- Understand stake-weight dynamics
Query Keys
| # | Name | Type | Description |
|---|---|---|---|
| 1 | netuid | u16 | netuid (u16, hashed key component) |
Stored Value
Kappa (u16)
Relationships
Modified By
Related Events
Code Examples
import { createClient, Binary } from "polkadot-api";
import { getWsProvider } from "polkadot-api/ws";
import { sub } from "@polkadot-api/descriptors"; // generated by: npx papi add sub -w wss://entrypoint-finney.opentensor.ai:443
const client = createClient(getWsProvider("wss://entrypoint-finney.opentensor.ai:443"));
const api = client.getTypedApi(sub);
// Query Kappa storage
const netuid = 1;
const result = await api.query.SubtensorModule.Kappa.getValue(netuid);
console.log("Kappa:", result);Version History
v101 block 1 Added
v123 block 720,235 Internal re-bind
v149 block 3,014,339 Internal re-bind
v166–v194 · runtime versions skipped on chain (never deployed)
v195 block 3,791,350 Internal re-bind
v278–v289 · runtime versions skipped on chain (never deployed)
v290 block 5,947,548 Internal re-bind Current
Runtime Info
View Source- Pallet
- SubtensorModule
- Storage Kind
- Map
- First Version
- v101
- Current Version
- v411