mirrors/bisq
1
0
Fork 0
mirror of https://github.com/bisq-network/bisq.git synced 2024-11-19 09:52:23 +01:00
Code Issues Packages Projects Releases Wiki Activity

Use TreeMap to prevent potential nondeterminism in BM share summation

Browse Source 
Replace HashMap in 'BurningManService.getBurningManCandidatesByName'
result construction with a TreeMap, to ensure that the map values are
ordered deterministically (alphabetically by candidate name) when
computing floating point sums. The map values are streamed over in a few
places in this method and elsewhere in 'DelayedPayoutTxReceiverService',
when performing double precision summation to compute the DPT. This
introduces potential nondeterminism due to the nonassociativity of FP
addition, making sums dependent on the term order.

(Note that 'DoubleStream::sum' uses compensated (Kahan) summation, which
makes it effectively quad precision internally, so the chance of term
reordering causing the result to differ by even a single ULP is probably
quite low here. So there might not be much problem in practice.)
This commit is contained in:
Steven Barclay 2023-11-26 03:41:03 +08:00
parent c234c2351c
commit 7dfd6aa5e1
No known key found for this signature in database
GPG Key ID: 9FED6BF1176D500B
1 changed files with 3 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
core/src/main/java/bisq/core/dao/burningman/BurningManService.java
View File

@ -48,6 +48,7 @@ import java.util.HashSet;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import java.util.TreeMap;
import java.util.stream.Collectors;
import java.util.stream.Stream;
@ -111,7 +112,7 @@ public class BurningManService {
///////////////////////////////////////////////////////////////////////////////////////////
Map<String, BurningManCandidate> getBurningManCandidatesByName(int chainHeight) {
Map<String, BurningManCandidate> burningManCandidatesByName = new HashMap<>();
Map<String, BurningManCandidate> burningManCandidatesByName = new TreeMap<>();
Map<P2PDataStorage.ByteArray, Set<TxOutput>> proofOfBurnOpReturnTxOutputByHash = getProofOfBurnOpReturnTxOutputByHash(chainHeight);
// Add contributors who made a compensation request
@ -120,8 +121,7 @@ public class BurningManService {
.forEach(issuance -> {
getCompensationProposalsForIssuance(issuance).forEach(compensationProposal -> {
String name = compensationProposal.getName();
burningManCandidatesByName.putIfAbsent(name, new BurningManCandidate());
BurningManCandidate candidate = burningManCandidatesByName.get(name);
BurningManCandidate candidate = burningManCandidatesByName.computeIfAbsent(name, n -> new BurningManCandidate());
// Issuance
Optional<String> customAddress = compensationProposal.getBurningManReceiverAddress();