mirror of
https://gitlab.com/pulsechaincom/prysm-pulse.git
synced 2024-12-25 21:07:18 +00:00
85 lines
3.3 KiB
Go
85 lines
3.3 KiB
Go
package casper
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import (
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"github.com/ethereum/go-ethereum/common"
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"github.com/prysmaticlabs/prysm/beacon-chain/params"
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"github.com/prysmaticlabs/prysm/beacon-chain/utils"
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pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
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)
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// ShuffleValidatorsToCommittees shuffles validator indices and splits them by slot and shard.
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func ShuffleValidatorsToCommittees(seed common.Hash, activeValidators []*pb.ValidatorRecord, crosslinkStartShard uint64) ([]*pb.ShardAndCommitteeArray, error) {
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indices := ActiveValidatorIndices(activeValidators)
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// split the shuffled list for slot.
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shuffledValidators, err := utils.ShuffleIndices(seed, indices)
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if err != nil {
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return nil, err
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}
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return splitBySlotShard(shuffledValidators, crosslinkStartShard), nil
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}
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// InitialShardAndCommitteesForSlots initialises the committees for shards by shuffling the validators
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// and assigning them to specific shards.
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func InitialShardAndCommitteesForSlots(validators []*pb.ValidatorRecord) ([]*pb.ShardAndCommitteeArray, error) {
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seed := make([]byte, 0, 32)
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committees, err := ShuffleValidatorsToCommittees(common.BytesToHash(seed), validators, 1)
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if err != nil {
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return nil, err
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}
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// Starting with 2 cycles (128 slots) with the same committees.
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return append(committees, committees...), nil
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}
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// splitBySlotShard splits the validator list into evenly sized committees and assigns each
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// committee to a slot and a shard. If the validator set is large, multiple committees are assigned
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// to a single slot and shard. See getCommitteesPerSlot for more details.
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func splitBySlotShard(shuffledValidators []uint32, crosslinkStartShard uint64) []*pb.ShardAndCommitteeArray {
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committeesPerSlot := getCommitteesPerSlot(len(shuffledValidators))
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committeBySlotAndShard := []*pb.ShardAndCommitteeArray{}
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// split the validator indices by slot.
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validatorsBySlot := utils.SplitIndices(shuffledValidators, int(params.GetConfig().CycleLength))
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for i, validatorsForSlot := range validatorsBySlot {
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shardCommittees := []*pb.ShardAndCommittee{}
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validatorsByShard := utils.SplitIndices(validatorsForSlot, committeesPerSlot)
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shardStart := int(crosslinkStartShard) + i*committeesPerSlot
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for j, validatorsForShard := range validatorsByShard {
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shardID := (shardStart + j) % params.GetConfig().ShardCount
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shardCommittees = append(shardCommittees, &pb.ShardAndCommittee{
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Shard: uint64(shardID),
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Committee: validatorsForShard,
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})
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}
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committeBySlotAndShard = append(committeBySlotAndShard, &pb.ShardAndCommitteeArray{
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ArrayShardAndCommittee: shardCommittees,
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})
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}
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return committeBySlotAndShard
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}
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// getCommitteesPerSlot calculates the parameters for ShuffleValidatorsToCommittees.
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// The minimum value for committeesPerSlot is 1.
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// Otherwise, the value for committeesPerSlot is the smaller of
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// numActiveValidators / CycleLength / (MinCommitteeSize*2) + 1 or
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// ShardCount / CycleLength.
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func getCommitteesPerSlot(numActiveValidators int) int {
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cycleLength := int(params.GetConfig().CycleLength)
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boundOnValidators := numActiveValidators/cycleLength/int(params.GetConfig().MinCommiteeSize*2) + 1
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boundOnShardCount := params.GetConfig().ShardCount / cycleLength
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// Ensure that comitteesPerSlot is at least 1.
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if boundOnShardCount == 0 {
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return 1
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} else if boundOnValidators > boundOnShardCount {
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return boundOnShardCount
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}
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return boundOnValidators
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}
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