# rho (/docs/hyperparameters/rho)

`rho` sets the temperature (steepness) of the sigmoid that maps a validator's
consensus alignment to trust in the classic Yuma Consensus formulation. Subnet
owners tuning how sharply the network rewards agreement with consensus are the
main audience.

## How it works [#how-it-works]

The formula lives in `sigmoid_safe` (`pallets/subtensor/src/epoch/math.rs`):

```
trust = 1 / (1 + e^(−rho × (x − kappa)))
```

where `x` is the stake fraction aligned with a validator's view and
[`kappa`](/docs/hyperparameters/kappa) is the midpoint. Higher `rho` makes the
curve steeper: alignment just above `kappa` maps to trust near 1, just below
to near 0. The recommended range in the code is 0 to 40; the mainnet
default is 10.

One caveat, straight from the source: the current epoch
(`pallets/subtensor/src/epoch/run_epoch.rs`) computes consensus as the
`kappa`-weighted median of weights and clips to it — the helper that would
feed `rho` into the sigmoid (`get_float_rho`) is defined but not called on
the active path. `rho` remains a stored, owner-settable parameter of the
Yuma formulation, but changing it does not alter today's epoch output. See
[Yuma Consensus](/docs/concepts/emissions#yuma-consensus) for the full
pipeline.

<HyperparamConsensusSigmoid focus="rho" />

## Reading and setting [#reading-and-setting]

Inspect with:

```
btcli sudo get --netuid N --name rho
```

Owner-settable:

```
btcli sudo set --netuid N --name rho --value 10
```

The value is a plain integer (stored as u16), not a fraction.

## Related [#related]

[`kappa`](/docs/hyperparameters/kappa) ·
[`tempo`](/docs/hyperparameters/tempo) ·
[`activity_cutoff`](/docs/hyperparameters/activity-cutoff) ·
[`max_validators`](/docs/hyperparameters/max-validators)