Subnet Configuration (Hyperparameters)
Bittensor subnets are configured with a set of state variables (known as hyperparameters) that are recorded on the blockchain. Many of these can be accessed (viewed and set) using the Bittensor CLI btcli, but some of them must be checked or set using Subtensor extrinsics, as noted.
Note that the names of the variables may be slightly different in various representations, e.g. in btcli and in the chain codebase.
Manage hyperparams with btcli
Not all hyperparameters can be viewed and set with btcli.
View the hyperparameters
Anyone can view the parameters of any subnet.
Example
btcli subnet hyperparameters --netuid 19
Netuid: 19
Using the specified network test from config
Subnet Hyperparameters
NETUID: 19 (inference) - Network: test
HYPERPARAMETER VALUE NORMALIZED
────────────────────────────────────────────────────────────────────────
rho 10 10
kappa 32767 0.4999923705
immunity_period 5000 5000
min_allowed_weights 1 1
max_weights_limit 65535 65535
tempo 99 99
min_difficulty 10000000 5.421010862e-13
max_difficulty 18446744073709551615 1
weights_version 0 0
weights_rate_limit 100 100
adjustment_interval 360 360
activity_cutoff 5000 5000
registration_allowed True True
target_regs_per_interval 1 1
min_burn 500000 τ 0.0005
max_burn 100000000000 τ 100.0000
bonds_moving_avg 900000 4.878909776e-14
max_regs_per_block 1 1
serving_rate_limit 50 50
max_validators 64 64
adjustment_alpha 58000 3.1441863e-15
difficulty 10000000 5.421010862e-13
commit_reveal_period 1 1
commit_reveal_weights_enabled False False
alpha_high 58982 0.9000076295
alpha_low 45875 0.7000076295
liquid_alpha_enabled False False
────────────────────────────────────────────────────────────────────────
btcli does not include all of the chain state variables, some of which can only be accessed through the Bittensor Python SDK or directly through extrinsic calls.
Set hyperparameters
Use the below command to set these hyperparameters.
Only the coldkey that created the subnet can set the hyperparameters.
btcli sudo set
Subnet Hyperparameters
The following variables are configurable by the subnet creator.
Permissions required to set: Subnet Creator
ActivityCutoff
Type: u16
Default: 5000
btcli setter: btcli sudo set --param activity_cutoff
Setter extrinsic: sudo_set_activity_cutoff
Permissions required to set: Subnet Creator
Description:
The number of blocks for the stake to become inactive for the purpose of epoch in Yuma Consensus. If a validator doesn't submit weights within the first ActivityCutoff blocks of the epoch, it will not be able to participate until the start of the next epoch.
AdjustmentAlpha
Type: u64
Default: 0
btcli setter: btcli sudo set --param adjustment_alpha
Setter extrinsic: sudo_set_activity_cutoff
Permissions required to set: Subnet Creator
Description:
AdjustmentAlpha is the rate at which difficulty and burn are adjusted up or down.
AdjustmentInterval
Type: u16
Default: 360
btcli setter: btcli sudo set --param adjustment_interval
Setter extrinsic: sudo_set_adjustment_interval
Permissions required to set: Subnet Creator
Description:
AdjustmentInterval is number of blocks that pass between difficulty and burn adjustments. So, I was wrong about "next block" when I said that if root sets difficulty outside of range, it will get back in range. Difficulty will get back in range at most after AdjustmentInterval blocks pass.
BondsMovingAverage
Type:
Default:
btcli setter: bonds_moving_avg
btcli setter: btcli sudo set --param sudo_set_bonds_moving_average
Permissions required to set: Subnet Creator
Description:
The moving average of bonds. The higher bonds yield to higher dividends for validators.
See Yuma Consensus: bonding mechanics.
BondsPenalty
Type: u16
Default: 0
btcli setter: none
Setter extrinsic: sudo_set_bonds_penalty
Permissions required to set: root
Description: The magnitude of the penalty subtracted from weights for exceeding consensus, for a specific subnet.
See Yuma Consensus: Penalizing out-of-consensus bonds.
CommitRevealPeriod
Type: u16
Default: 1
btcli setter: btcli sudo set --param commit_reveal_period
Setter extrinsic: sudo_set_commit_reveal_weights_interval
Permissions required to set: Subnet Creator
Description:
How long, in blocks, the consensus weights for a subnet remain time-lock encrypted, preventing weight-copying.
See Commit Reveal
CommitRevealWeightsEnabled
Type: Boolean
Default: false
btcli setter: yes
Setter extrinsic: sudo_set_commit_reveal_weights_enabled
Permissions required to set: Subnet Creator
Description:
Enables Commit Reveal
Difficulty
Type: u64
Default: 10000000
btcli setter: none
Setter extrinsic: sudo_set_difficulty
Permissions required to set: Root
Description:
Current dynamically computed value for the proof-of-work (POW) requirement for POW hotkey registration. Decreases over time but increases after new registrations, between the min and the maximum set by the subnet creator. see [#max-difficulty].
ImmunityPeriod
Type: u16
Default: 5000
btcli setter: yes
Setter extrinsic: sudo_set_immunity_period
Permissions required to set: Subnet creator
Description:
The number of blocks after registration when a miner is protected from deregistration
Kappa
Type: u16
Default: 32767 ( or approximately 0.5 normalized )
btcli setter: yes
Setter extrinsic: sudo_set_kappa
Permissions required to set: Subnet creator
Description:
The consensus majority ratio: The weights set by validators who have lower normalized stake than Kappa are not used in calculating consensus, which affects ranks, which affect incentives.
the consensus threshold for bond-clipping during Yuma Consensus
LiquidAlphaEnabled
Type: Bool
Default: False
btcli setter: btcli sudo set --param liquid_alpha_enabled
Setter extrinsic: sudo_set_liquid_alpha_enabled
Permissions required to set: SN creator
Description:
Enables the liquid alpha feature.
MaxAllowedValidators
Type: u16
Default: 64
btcli setter: btcli sudo set --param max_validators
Setter extrinsic: sudo_set_max_allowed_validators
Permissions required to set: Root
Description:
Maximum validators on a subnet.
MaxBurn
Type: u64
Default: 100000000000 normalized to 100.0000(τ)
btcli setter: btcli sudo set --param max_burn
Setter extrinsic: sudo_set_max_burn
Permissions required to set: Subnet creator
Description:
The maximum of the dynamic range for TAO cost of burn registration on the subnet.
MaxDifficulty
Type: u64
Default: 18446744073709551615 normalized to 1
btcli setter: btcli sudo set --param min_difficulty
Setter extrinsic:
Permissions required to set: Subnet creator
Description:
The maximum of the dynamic range for difficulty of proof-of-work registration on the subnet.
MaxRegistrationsPerBlock
Type: u16
Default: 1
btcli setter: btcli sudo set --param max_regs_per_block
Setter extrinsic: sudo_set_max_registrations_per_block
Permissions required to set: Subnet creator
Description:
Maximum neuron registrations per block. Note: Actual limit may be lower, as there is also per interval limit TargetRegistrationsPerInterval.
MaxWeightsLimit
Type: u16
Default: 65535
btcli setter: btcli sudo set --param max_weights_limit
Setter extrinsic: sudo_set_max_weight_limit
Permissions required to set: Subnet creator
Description: The limit for the u16-normalized weights. If some weight is greater than this limit when all weights are normalized so that maximum weight is 65535, then it will not be used.
MinAllowedWeights
Type: u16
Default: 1
btcli setter: btcli sudo set --param min_allowed_weights
Setter extrinsic: sudo_set_min_allowed_weights
Permissions required to set: Subnet creator
Description: Minimum number of weights for a validator to set when setting weights.
MinBurn
Type: u64
Default: 500000 normalized to 0.0005(τ)
btcli setter: btcli sudo set --param min_burn
Setter extrinsic: sudo_set_min_burn
Permissions required to set: Subnet creator
Description:
The minimum of the range of the dynamic burn cost for registering on the subnet.
MinDifficulty
Type: u64
Default: 10000000 normalized to 5.421010862e-13
btcli setter: btcli sudo set --param min_difficulty
Setter extrinsic: sudo_set_min_difficulty
Permissions required to set: Subnet creator
Description:
The minimum of the range of the proof-of-work for registering on the subnet
NetworkPowRegistrationAllowed
Type: Boolean
Default: False
btcli setter: none
Setter extrinsic: sudo_set_network_pow_registration_allowed
Permissions required to set: Subnet creator
Description:
NetworkPowRegistrationAllowed is a flag that toggles PoW registrations on a subnet
NetworkRateLimit
Type: u64
Default: 7200
btcli setter: none
Setter extrinsic:
Permissions required to set: root
Description:
Rate limit for network registrations expressed in blocks
NetworkRegistrationAllowed
Type: Boolean
Default: True
btcli setter: btcli sudo set --param registration_allowed
Setter extrinsic: sudo_set_network_registration_allowed
Permissions required to set: Subnet creator
Description:
NetworkRegistrationAllowed determines if burned registrations are allowed. If both burned and pow registrations are disabled, the subnet will not get emissions.
Rho
Type: u16
Default: 10
btcli setter: yes
Setter extrinsic: sudo_set_rho
Permissions required to set: Subnet creator
Description:
Deprecated.
ServingRateLimit
Type: u16
Default: 50
btcli setter:
Setter extrinsic: sudo_set_serving_rate_limit
Permissions required to set: Subnet creator
Description:
Rate limit for calling serve_axon and serve_prometheus extrinsics used by miners.
TargetRegistrationsPerInterval
Type: u16
Default: 1
btcli command: btcli sudo set --param target_regs_per_interval
Setter extrinsic: sudo_set_target_registrations_per_interval
Permissions required to set: root
Description:
Maximum number of neuron registrations allowed per interval. Interval is AdjustmentInterval
Tempo
Type: u16
Default: 360
btcli setter: btcli sudo set --param tempo
Setter extrinsic: sudo_set_tempo
Permissions required to set: root
Description:
Length of subnet tempo in blocks. See Emission
ToggleTransfer
Type: Boolean
Default: True
btcli setter: none
Setter extrinsic: sudo_set_toggle_transfer
Permissions required to set: Subnet creator
Description:
Allows/disallows transfer of stake between coldkeys.
WeightsVersion
Type: u16
Default: 0
btcli setter: btcli sudo set --param weights_version
Setter extrinsic: sudo_set_weights_version_key
Permissions required to set: Subnet Creator
Description:
If the version key specified in set_weights extrinsic is lower than this system-wide setting (WeightsVersionKey), the transaction will fail. This is a fool-proofing protection for validators to update, not a security feature.
WeightsRateLimit / CommitmentRateLimit
Type: u12
Default: 100
btcli setter: btcli sudo set --param weights_rate_limit
Setter extrinsic:
Permissions required to set: Root
Description:
How long, in blocks, a validator must wait between weight commits on a subnet.
Global/Root State Variables
The following variables are global and/or can only be configured with root permissions, which are held by a triumvirate of Opentensor Foundation employees. They are listed here for reference.
ColdkeySwapScheduleDuration
Type: u12
Default:
btcli setter: no
Setter extrinsic: sudo_set_coldkey_swap_schedule_duration
Permissions required to set: Root
Description:
The duration in blocks of the waiting period before a coldkey swap.
Issuance
Type: u64
Description: Refers to total issuance, the amount of TAO in circulation.
LockReductionInterval
Type: u64
Default: 14 * 7200
btcli setter:
Setter extrinsic:
Permissions required to set: root
Description:
The number of blocks that need to pass in order for the network lock cost to half.
sudo_set_lock_reduction_interval| root
NetworkMinLockCost
btcli setter: none
Setter extrinsic: sudo_set_network_min_lock_cost
Permissions required to set: root
Description:
NetworkMinLockCost is the minimum TAO to pay for subnet registration
StakeThreshold
Type: u12
Default: 1000
btcli setter: none
Setter extrinsic: sudo_set_stake_threshold
Permissions required to set: root
Description:
The minimum stake required for validating. Currently 1000
TxDelegateTakeRateLimit
Type: u64
Default: 216000
btcli setter:
Setter extrinsic:
Permissions required to set: root
Description:
Rate limit of how frequently can a delegate take be increased
DissolveNetworkScheduleDuration
Deprecated
EmissionValue
Description:
Deprecated. replaced with SubnetAlphaInEmission, SubnetAlphaOutEmission, and SubnetTaoInEmission.
EvmChainId
Permissions required to set: root
Description:
The Chain ID. 945 for Bittensor mainnet, a.k.a. Finney.
TxRateLimit
Type: u64
Default: 1000
btcli setter: none
Setter extrinsic: sudo_set_tx_rate_limit
Permissions required to set: root
Description:
Rate limit for swap_hotkey extrinsic.
SubnetOwnerCut
btcli setter: none
Setter extrinsic: sudo_set_subnet_owner_cut
Permissions required to set: root
Description:
The ratio of all subnet alpha emissions that is given to subnet owner as stake. (Global, fixed at 18%.)