ugdmint/

README

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x/ugdmint

Contents

• State
  • Minter
  • Params
• Begin-Block
  • BlockProvision
• Parameters
• Events
  • BeginBlocker
• Client
  • CLI
  • gRPC
  • REST

Concepts

The Minting Mechanism

The Unigrid minting mechanism was designed to:

• gradually decrease minting amount as a chain ages

As a chain ages, meaning the block height increases, the minting reward will decrease until eventually minting rewards are exhausted.

Currently minting rewards will step down at hard coded height changes. The first block in the chain receives the largest reward, then it steps down as shown in the following chart:

height	amount
1	1200000
2 - 4999	1
5000 - 1049999	8
1050000 - 2099999	6
2100000 - 3149999	4
3150000 - 4199999	2
> 4199999	1

Subsidy-halving-interval is the one parameter that may adjust how long minting rewards continue, and at what rate the amount will decrease as the block height increases. This decrease effect is applied to the rewards amount determined from the chart above. Currently this decrease effect kicks in after a height of 1000000 blocks. The interval is how often the minting amount will decrease after the threshold of 1000000 has been reached. Each decrease interval will reduce the minting amount by an additional 1% until 100% is taken away.

State

Minter

The minter is a space for holding current subsidy-halving-interval.

• Minter: 0x00 -> ProtocolBuffer(minter)

// Minter represents the minting state.
message Minter {
  // current subsidy halving interval
  string subsidy_halving_interval = 1 [
    (cosmos_proto.scalar)  = "cosmos.Dec",
    (gogoproto.customtype) = "cosmossdk.io/math.LegacyDec",
    (gogoproto.nullable)   = false
  ];
}

Params

The ugdmint module stores it's params in state with the prefix of 0x01, it can be updated with governance or the address with authority.

• Params: ugdmint/params -> legacy_amino(params)

// Params defines the parameters for the module.
message Params {
  option (gogoproto.goproto_stringer) = false;
  option (amino.name)                 = "cosmos-sdk/x/ugdmint/Params";

  // type of coin to mint
  string mint_denom = 1;
  // subsidy halving interval
  string subsidy_halving_interval = 2 [
    (cosmos_proto.scalar)  = "cosmos.Dec",
    (gogoproto.customtype) = "cosmossdk.io/math.LegacyDec",
    (gogoproto.nullable)   = false
  ];
  // goal of percent bonded atoms
  string goal_bonded = 3 [
    (cosmos_proto.scalar)  = "cosmos.Dec",
    (gogoproto.customtype) = "cosmossdk.io/math.LegacyDec",
    (gogoproto.nullable)   = false
  ];
  // expected blocks per year
  uint64 blocks_per_year = 4;
}

Begin-Block

Minting parameters are recalculated and paid at the beginning of each block.

BlockProvision

Calculate the provisions generated for each block based on current block height. The provisions are then minted by the ugdmint module's ModuleMinterAccount and then transferred to the auth's FeeCollector ModuleAccount.

BlockProvision(params Params, height uint64) sdk.Coin {

  nSubsidy := 1

  if (height == 1) {
    nSubsidy = 1200000
  } else if (height >= 5000 && height < 1050000) {
    nSubsidy = 8
  } else if (height >= 1050000 && height < 2100000) {
    nSubsidy = 6
  } else if (height >= 2100000 && height < 3150000) {
    nSubsidy = 4
  } else if (height >= 3150000 && height < 4200000) {
    nSubsidy = 2
  } else if (height >= 4200000 && height < 12600000) {
    nSubsidy = 1
  }

  if (height > 1000000) {
    nBehalf := sdk.NewDec(int64(height - 100000)).Quo(params.SubsidyHalvingInterval).TruncateInt().Int64()
    
    for i := 0; i < int(nBehalf); i++ {
      nSubsidy = nSubsidy * 99 / 100
    }
  }

  provisionAmt := sdk.NewInt(int64(nSubsidy))
  // provisionAmt := m.AnnualProvisions.QuoInt(sdk.NewInt(int64(params.BlocksPerYear)))
  return sdk.NewCoin(params.MintDenom, provisionAmt)
}

Parameters

The minting module contains the following parameters:

Key	Type	Example
MintDenom	string	"uatom"
SubsidyHalvingInterval	string (dec)	"1000000.000000000000"
GoalBonded	string (dec)	"0.670000000000000000"
BlocksPerYear	string (uint64)	"6311520"

Events

The minting module emits the following events:

BeginBlocker

Type	Attribute Key	Attribute Value
ugdmint	bonded_ratio	{bondedRatio}
ugdmint	subsidy_halving_interval	{subsidyHalvingInterval}
ugdmint	amount	{amount}

Client

CLI

A user can query and interact with the ugdmint module using the CLI.

Query

The query commands allow users to query ugdmint state.

simd query ugdmint --help

inflation

The subsidy-halving-interval command allow users to query the current minting subsidyHalvingInterval value

simd query ugdmint subsidy-halving-interval [flags]

Example:

simd query ugdmint subsidy-halving-interval

Example Output:

1000000.00

params

The params command allow users to query the current minting parameters

simd query ugdmint params [flags]

Example:

blocks_per_year: "4360000"
goal_bonded: "0.670000000000000000"
subsidy_halving_interval: "1000000.000000000000000000"
mint_denom: ugd

gRPC

A user can query the ugdmint module using gRPC endpoints.

SubsidyHalvingInterval

The SubsidyHalvingInterval endpoint allow users to query the current minting subsidyHalvingInterval value

/cosmos.ugdmint.v1beta1.Query/SubsidyHalvingInterval

Example:

grpcurl -plaintext localhost:9090 cosmos.ugdmint.v1beta1.Query/SubsidyHalvingInterval

Example Output:

{
  "subsidyHalvingInterval": "1000000.00"
}

Params

The Params endpoint allow users to query the current minting parameters

/cosmos.ugdmint.v1beta1.Query/Params

Example:

grpcurl -plaintext localhost:9090 cosmos.ugdmint.v1beta1.Query/Params

Example Output:

{
  "params": {
    "mintDenom": "ugd",
    "subsidyHalvingInterval": "1000000.00000000000",
    "goalBonded": "0.670000000000000000",
    "blocksPerYear": "6311520"
  }
}

REST

A user can query the ugdmint module using REST endpoints.

subsidyHalvingInterval

/cosmos/ugdmint/v1beta1/subsidyHalvingInterval

Example:

curl "localhost:1317/cosmos/ugdmint/v1beta1/subsidyHalvingInterval"

Example Output:

{
  "subsidyHalvingInterval": "1000000.00"
}

params

/cosmos/ugdmint/v1beta1/params

Example:

curl "localhost:1317/cosmos/ugdmint/v1beta1/params"

Example Output:

{
  "params": {
    "mintDenom": "ugd",
    "subsidyHalvingInterval": "1000000.00000000000",
    "goalBonded": "0.670000000000000000",
    "blocksPerYear": "6311520"
  }
}