core: vm: automatically calculate notary set size (#276)

4 files changed, 96 insertions, 15 deletions

diff --git a/core/governance.go b/core/governance.go
index db0e60b6c..da310a1cd 100644
--- a/core/governance.go
+++ b/core/governance.go
@@ -99,7 +99,7 @@ func (g *Governance) Configuration(round uint64) *coreTypes.Config {
 	return &coreTypes.Config{
 		LambdaBA:         time.Duration(c.LambdaBA) * time.Millisecond,
 		LambdaDKG:        time.Duration(c.LambdaDKG) * time.Millisecond,
-		NotarySetSize:    c.NotarySetSize,
+		NotarySetSize:    uint32(configHelper.NotarySetSize().Uint64()),
 		DKGSetSize:       c.DKGSetSize,
 		RoundLength:      c.RoundLength,
 		MinBlockInterval: time.Duration(c.MinBlockInterval) * time.Millisecond,
diff --git a/core/vm/oracle_contract_abi.go b/core/vm/oracle_contract_abi.go
index 369c9ec17..af0affece 100644
--- a/core/vm/oracle_contract_abi.go
+++ b/core/vm/oracle_contract_abi.go
@@ -141,6 +141,20 @@ const GovernanceABIJSON = `
   {
     "constant": true,
     "inputs": [],
+    "name": "notaryParamBeta",
+    "outputs": [
+      {
+        "name": "",
+        "type": "uint256"
+      }
+    ],
+    "payable": false,
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "constant": true,
+    "inputs": [],
     "name": "miningVelocity",
     "outputs": [
       {
@@ -196,6 +210,20 @@ const GovernanceABIJSON = `
   },
   {
     "constant": true,
+    "inputs": [],
+    "name": "notaryParamAlpha",
+    "outputs": [
+      {
+        "name": "",
+        "type": "uint256"
+      }
+    ],
+    "payable": false,
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "constant": true,
     "inputs": [
       {
         "name": "",
@@ -817,11 +845,11 @@ const GovernanceABIJSON = `
         "type": "uint256"
       },
       {
-        "name": "NotarySetSize",
+        "name": "NotaryParamAlpha",
         "type": "uint256"
       },
       {
-        "name": "DKGSetSize",
+        "name": "NotaryParamBeta",
         "type": "uint256"
       },
       {
diff --git a/core/vm/oracle_contracts.go b/core/vm/oracle_contracts.go
index b8eb4fedc..e30d0382a 100644
--- a/core/vm/oracle_contracts.go
+++ b/core/vm/oracle_contracts.go
@@ -21,6 +21,7 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
+	"math"
 	"math/big"
 	"sort"
 
@@ -84,6 +85,8 @@ const (
 	lambdaBALoc
 	lambdaDKGLoc
 	notarySetSizeLoc
+	notaryParamAlphaLoc
+	notaryParamBetaLoc
 	dkgSetSizeLoc
 	roundLengthLoc
 	minBlockIntervalLoc
@@ -816,11 +819,43 @@ func (s *GovernanceState) LambdaDKG() *big.Int {
 func (s *GovernanceState) NotarySetSize() *big.Int {
 	return s.getStateBigInt(big.NewInt(notarySetSizeLoc))
 }
+func (s *GovernanceState) CalNotarySetSize() {
+	nodeSetSize := float64(len(s.QualifiedNodes()))
+	setSize := math.Ceil((nodeSetSize*0.6-1)/3)*3 + 1
+
+	if nodeSetSize >= 80 {
+		alpha := float64(s.NotaryParamAlpha().Uint64()) / decimalMultiplier
+		beta := float64(s.NotaryParamBeta().Uint64()) / decimalMultiplier
+		setSize = math.Ceil(alpha*math.Log(nodeSetSize) - beta)
+	}
+	s.setStateBigInt(big.NewInt(notarySetSizeLoc), big.NewInt(int64(setSize)))
+}
+
+// uint256 public notaryParamAlpha;
+func (s *GovernanceState) NotaryParamAlpha() *big.Int {
+	return s.getStateBigInt(big.NewInt(notaryParamAlphaLoc))
+}
+
+// uint256 public notaryParamBeta;
+func (s *GovernanceState) NotaryParamBeta() *big.Int {
+	return s.getStateBigInt(big.NewInt(notaryParamBetaLoc))
+}
 
 // uint256 public dkgSetSize;
 func (s *GovernanceState) DKGSetSize() *big.Int {
 	return s.getStateBigInt(big.NewInt(dkgSetSizeLoc))
 }
+func (s *GovernanceState) CalDKGSetSize() {
+	nodeSetSize := float64(len(s.QualifiedNodes()))
+	setSize := math.Ceil((nodeSetSize*0.6-1)/3)*3 + 1
+
+	if nodeSetSize >= 100 {
+		alpha := float64(s.NotaryParamAlpha().Uint64()) / decimalMultiplier
+		beta := float64(s.NotaryParamBeta().Uint64()) / decimalMultiplier
+		setSize = math.Ceil(alpha*math.Log(nodeSetSize) - beta)
+	}
+	s.setStateBigInt(big.NewInt(dkgSetSizeLoc), big.NewInt(int64(setSize)))
+}
 
 // uint256 public roundLength;
 func (s *GovernanceState) RoundLength() *big.Int {
@@ -939,8 +974,8 @@ func (s *GovernanceState) Configuration() *params.DexconConfig {
 		BlockGasLimit:     s.getStateBigInt(big.NewInt(blockGasLimitLoc)).Uint64(),
 		LambdaBA:          s.getStateBigInt(big.NewInt(lambdaBALoc)).Uint64(),
 		LambdaDKG:         s.getStateBigInt(big.NewInt(lambdaDKGLoc)).Uint64(),
-		NotarySetSize:     uint32(s.getStateBigInt(big.NewInt(notarySetSizeLoc)).Uint64()),
-		DKGSetSize:        uint32(s.getStateBigInt(big.NewInt(dkgSetSizeLoc)).Uint64()),
+		NotaryParamAlpha:  float32(s.getStateBigInt(big.NewInt(notaryParamAlphaLoc)).Uint64()) / decimalMultiplier,
+		NotaryParamBeta:   float32(s.getStateBigInt(big.NewInt(notaryParamBetaLoc)).Uint64()) / decimalMultiplier,
 		RoundLength:       s.getStateBigInt(big.NewInt(roundLengthLoc)).Uint64(),
 		MinBlockInterval:  s.getStateBigInt(big.NewInt(minBlockIntervalLoc)).Uint64(),
 		FineValues:        s.FineValues(),
@@ -958,11 +993,15 @@ func (s *GovernanceState) UpdateConfiguration(cfg *params.DexconConfig) {
 	s.setStateBigInt(big.NewInt(blockGasLimitLoc), big.NewInt(int64(cfg.BlockGasLimit)))
 	s.setStateBigInt(big.NewInt(lambdaBALoc), big.NewInt(int64(cfg.LambdaBA)))
 	s.setStateBigInt(big.NewInt(lambdaDKGLoc), big.NewInt(int64(cfg.LambdaDKG)))
-	s.setStateBigInt(big.NewInt(notarySetSizeLoc), big.NewInt(int64(cfg.NotarySetSize)))
-	s.setStateBigInt(big.NewInt(dkgSetSizeLoc), big.NewInt(int64(cfg.DKGSetSize)))
+	s.setStateBigInt(big.NewInt(notaryParamAlphaLoc), big.NewInt(int64(cfg.NotaryParamAlpha*decimalMultiplier)))
+	s.setStateBigInt(big.NewInt(notaryParamBetaLoc), big.NewInt(int64(cfg.NotaryParamBeta*decimalMultiplier)))
 	s.setStateBigInt(big.NewInt(roundLengthLoc), big.NewInt(int64(cfg.RoundLength)))
 	s.setStateBigInt(big.NewInt(minBlockIntervalLoc), big.NewInt(int64(cfg.MinBlockInterval)))
 	s.SetFineValues(cfg.FineValues)
+
+	// Calculate set size.
+	s.CalNotarySetSize()
+	s.CalDKGSetSize()
 }
 
 type rawConfigStruct struct {
@@ -972,8 +1011,8 @@ type rawConfigStruct struct {
 	MinGasPrice      *big.Int
 	LambdaBA         *big.Int
 	LambdaDKG        *big.Int
-	NotarySetSize    *big.Int
-	DKGSetSize       *big.Int
+	NotaryParamAlpha *big.Int
+	NotaryParamBeta  *big.Int
 	RoundLength      *big.Int
 	MinBlockInterval *big.Int
 	FineValues       []*big.Int
@@ -987,11 +1026,14 @@ func (s *GovernanceState) UpdateConfigurationRaw(cfg *rawConfigStruct) {
 	s.setStateBigInt(big.NewInt(blockGasLimitLoc), cfg.BlockGasLimit)
 	s.setStateBigInt(big.NewInt(lambdaBALoc), cfg.LambdaBA)
 	s.setStateBigInt(big.NewInt(lambdaDKGLoc), cfg.LambdaDKG)
-	s.setStateBigInt(big.NewInt(notarySetSizeLoc), cfg.NotarySetSize)
-	s.setStateBigInt(big.NewInt(dkgSetSizeLoc), cfg.DKGSetSize)
+	s.setStateBigInt(big.NewInt(notaryParamAlphaLoc), cfg.NotaryParamAlpha)
+	s.setStateBigInt(big.NewInt(notaryParamBetaLoc), cfg.NotaryParamBeta)
 	s.setStateBigInt(big.NewInt(roundLengthLoc), cfg.RoundLength)
 	s.setStateBigInt(big.NewInt(minBlockIntervalLoc), cfg.MinBlockInterval)
 	s.SetFineValues(cfg.FineValues)
+
+	s.CalNotarySetSize()
+	s.CalDKGSetSize()
 }
 
 // event ConfigurationChanged();
@@ -1488,6 +1530,7 @@ func (g *GovernanceContract) updateConfiguration(cfg *rawConfigStruct) ([]byte,
 
 	g.state.UpdateConfigurationRaw(cfg)
 	g.state.emitConfigurationChangedEvent()
+
 	return nil, nil
 }
 
@@ -1530,6 +1573,9 @@ func (g *GovernanceContract) register(
 	if value.Cmp(big.NewInt(0)) > 0 {
 		g.state.IncTotalStaked(value)
 		g.state.emitStaked(caller, value)
+
+		g.state.CalNotarySetSize()
+		g.state.CalDKGSetSize()
 	}
 	return g.useGas(GovernanceActionGasCost)
 }
@@ -1557,6 +1603,10 @@ func (g *GovernanceContract) stake() ([]byte, error) {
 
 	g.state.IncTotalStaked(value)
 	g.state.emitStaked(caller, value)
+
+	g.state.CalNotarySetSize()
+	g.state.CalDKGSetSize()
+
 	return g.useGas(GovernanceActionGasCost)
 }
 
@@ -1591,6 +1641,9 @@ func (g *GovernanceContract) unstake(amount *big.Int) ([]byte, error) {
 	g.state.DecTotalStaked(amount)
 	g.state.emitUnstaked(caller, amount)
 
+	g.state.CalNotarySetSize()
+	g.state.CalDKGSetSize()
+
 	return g.useGas(GovernanceActionGasCost)
 }
 
diff --git a/core/vm/oracle_contracts_test.go b/core/vm/oracle_contracts_test.go
index 868ea533c..69e13e1a1 100644
--- a/core/vm/oracle_contracts_test.go
+++ b/core/vm/oracle_contracts_test.go
@@ -492,8 +492,8 @@ func (g *OracleContractsTestSuite) TestUpdateConfiguration() {
 		big.NewInt(8000000),
 		big.NewInt(250),
 		big.NewInt(2500),
-		big.NewInt(4),
-		big.NewInt(4),
+		big.NewInt(int64(70.5*decimalMultiplier)),
+		big.NewInt(264*decimalMultiplier),
 		big.NewInt(600),
 		big.NewInt(900),
 		[]*big.Int{big.NewInt(1), big.NewInt(1), big.NewInt(1)})
@@ -591,7 +591,7 @@ func (g *OracleContractsTestSuite) TestConfigurationReading() {
 	g.Require().NoError(err)
 	err = GovernanceABI.ABI.Unpack(&value, "notarySetSize", res)
 	g.Require().NoError(err)
-	g.Require().Equal(g.config.NotarySetSize, uint32(value.Uint64()))
+	g.Require().True(uint32(value.Uint64()) > 0)
 
 	// DKGRound.
 	input, err = GovernanceABI.ABI.Pack("dkgRound")
@@ -612,7 +612,7 @@ func (g *OracleContractsTestSuite) TestConfigurationReading() {
 	g.Require().NoError(err)
 	err = GovernanceABI.ABI.Unpack(&value, "dkgSetSize", res)
 	g.Require().NoError(err)
-	g.Require().Equal(g.config.DKGSetSize, uint32(value.Uint64()))
+	g.Require().True(uint32(value.Uint64()) > 0)
 
 	// RoundLength.
 	input, err = GovernanceABI.ABI.Pack("roundLength")