Get all beacon committees at once

beacon-chain/core/helpers/beacon_committee.go

@@ -82,6 +82,47 @@ func AttestationCommittees(ctx context.Context, st state.ReadOnlyBeaconState, at
  return committees, nil
 }
 
+// BeaconCommittees returns the list of all beacon committees for a given state at a given slot.
+func BeaconCommittees(ctx context.Context, state state.ReadOnlyBeaconState, slot primitives.Slot) ([][]primitives.ValidatorIndex, error) {
+ epoch := slots.ToEpoch(slot)
+ activeCount, err := ActiveValidatorCount(ctx, state, epoch)
+ if err != nil {
+ return nil, errors.Wrap(err, "could not compute active validator count")
+ }
+ committeesPerSlot := SlotCommitteeCount(activeCount)
+ seed, err := Seed(state, epoch, params.BeaconConfig().DomainBeaconAttester)
+ if err != nil {
+ return nil, errors.Wrap(err, "could not get seed")
+ }
+
+ committees := make([][]primitives.ValidatorIndex, committeesPerSlot)
+ var activeIndices []primitives.ValidatorIndex
+
+ for idx := primitives.CommitteeIndex(0); idx < primitives.CommitteeIndex(len(committees)); idx++ {
+ committee, err := committeeCache.Committee(ctx, slot, seed, idx)
+ if err != nil {
+ return nil, errors.Wrap(err, "could not interface with committee cache")
+ }
+ if committee != nil {
+ committees[idx] = committee
+ continue
+ }
+
+ if len(activeIndices) == 0 {
+ activeIndices, err = ActiveValidatorIndices(ctx, state, epoch)
+ if err != nil {
+ return nil, errors.Wrap(err, "could not get active indices")
+ }
+ }
+ committee, err = BeaconCommittee(ctx, activeIndices, seed, slot, idx)
+ if err != nil {
+ return nil, errors.Wrap(err, "could not compute beacon committee")
+ }
+ committees[idx] = committee
+ }
+ return committees, nil
+}
+
 // BeaconCommitteeFromState returns the crosslink committee of a given slot and committee index. This
 // is a spec implementation where state is used as an argument. In case of state retrieval
 // becomes expensive, consider using BeaconCommittee below.

beacon-chain/core/helpers/beacon_committee_test.go

@@ -18,6 +18,7 @@ import (
  ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
  "github.com/prysmaticlabs/prysm/v5/testing/assert"
  "github.com/prysmaticlabs/prysm/v5/testing/require"
+ "github.com/prysmaticlabs/prysm/v5/testing/util"
  "github.com/prysmaticlabs/prysm/v5/time/slots"
 )
 
@@ -749,3 +750,27 @@ func TestAttestationCommittees(t *testing.T) {
  assert.Equal(t, params.BeaconConfig().TargetCommitteeSize, uint64(len(committees[1])))
  })
 }
+
+func TestBeaconCommittees(t *testing.T) {
+ prevConfig := params.BeaconConfig().Copy()
+ defer params.OverrideBeaconConfig(prevConfig)
+ c := params.BeaconConfig().Copy()
+ c.MinGenesisActiveValidatorCount = 128
+ c.SlotsPerEpoch = 4
+ c.TargetCommitteeSize = 16
+ params.OverrideBeaconConfig(c)
+
+ state, _ := util.DeterministicGenesisState(t, 256)
+
+ activeCount, err := helpers.ActiveValidatorCount(context.Background(), state, 0)
+ require.NoError(t, err)
+ committeesPerSlot := helpers.SlotCommitteeCount(activeCount)
+ committees, err := helpers.BeaconCommittees(context.Background(), state, 0)
+ require.NoError(t, err)
+ require.Equal(t, committeesPerSlot, uint64(len(committees)))
+ for idx := primitives.CommitteeIndex(0); idx < primitives.CommitteeIndex(len(committees)); idx++ {
+ committee, err := helpers.BeaconCommitteeFromState(context.Background(), state, 0, idx)
+ require.NoError(t, err)
+ require.DeepEqual(t, committees[idx], committee)
+ }
+}