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Various renames
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@sipa
sipa committed Jun 16, 2023
1 parent 389f207 commit 8dbda3a
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Showing 2 changed files with 89 additions and 67 deletions.
107 changes: 65 additions & 42 deletions src/cluster_linearize.h
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Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,7 @@ namespace cluster_linearize {

namespace {

/** Wrapper around __builtin_ctz[l][l] for supporting unsigned integer types. */
/** Wrapper around __builtin_ctz* for supporting unsigned integer types. */
template<typename I>
unsigned inline CountTrailingZeroes(I v)
{
Expand All @@ -38,7 +38,7 @@ unsigned inline CountTrailingZeroes(I v)
}
}

/** Wrapper around __builtin_popcount[l][l] for supporting unsigned integer types. */
/** Wrapper around __builtin_popcount* for supporting unsigned integer types. */
template<typename I>
unsigned inline PopCount(I v)
{
Expand Down Expand Up @@ -189,32 +189,49 @@ class IntBitSet
};

public:
/** Number of elements this set type supports. */
static constexpr unsigned MAX_SIZE = std::numeric_limits<I>::digits;

/** Construct an empty set. */
IntBitSet() noexcept : m_val{0} {}
/** Copy a set. */
IntBitSet(const IntBitSet&) noexcept = default;
/** Copy-assign a set. */
IntBitSet& operator=(const IntBitSet&) noexcept = default;

/** Construct a set with elements 0..count-1. */
static IntBitSet Full(unsigned count) noexcept {
IntBitSet ret;
for (unsigned i = 0; i < count; ++i) ret.Set(i);
if (count) ret.m_val = (~I{0}) >> (MAX_SIZE - count);
return ret;
}

/** Compute the size of a set (number of elements). */
unsigned Count() const noexcept { return PopCount(m_val); }
void Set(unsigned pos) noexcept { m_val |= I{1U} << pos; }
/** Add an element to a set. */
void Add(unsigned pos) noexcept { m_val |= I{1U} << pos; }
/** Find if an element is in the set. */
bool operator[](unsigned pos) const noexcept { return (m_val >> pos) & 1U; }
bool None() const noexcept { return m_val == 0; }
bool Any() const noexcept { return m_val != 0; }
/** Check if a set is empty. */
bool IsEmpty() const noexcept { return m_val == 0; }
/** Construct an object that will produce all elements of this set, using Next(). */
BitPopper Elements() const noexcept { return BitPopper(m_val); }
/** Update this to be the union of this and a. */
IntBitSet& operator|=(const IntBitSet& a) noexcept { m_val |= a.m_val; return *this; }
/** Update this to be intersection of this and a. */
IntBitSet& operator&=(const IntBitSet& a) noexcept { m_val &= a.m_val; return *this; }
/** Construct a new set that is the interaction of a and b. */
friend IntBitSet operator&(const IntBitSet& a, const IntBitSet& b) noexcept { return IntBitSet{a.m_val & b.m_val}; }
/** Construct a new set that is the union of a and b. */
friend IntBitSet operator|(const IntBitSet& a, const IntBitSet& b) noexcept { return IntBitSet{a.m_val | b.m_val}; }
/** Construct a new set that is a minus b. */
friend IntBitSet operator/(const IntBitSet& a, const IntBitSet& b) noexcept { return IntBitSet{a.m_val & ~b.m_val}; }
friend bool operator<(const IntBitSet& a, const IntBitSet& b) noexcept { return a.m_val < b.m_val; }
/** Check if set a and set b are identical. */
friend bool operator!=(const IntBitSet& a, const IntBitSet& b) noexcept { return a.m_val != b.m_val; }
/** Check if set a and set b are different. */
friend bool operator==(const IntBitSet& a, const IntBitSet& b) noexcept { return a.m_val == b.m_val; }
/** Check if set a is a superset of set b. */
friend bool operator>>(const IntBitSet& a, const IntBitSet& b) noexcept { return (b.m_val & ~a.m_val) == 0; }
};

/** A bitset implementation backed by N integers of type I. */
Expand Down Expand Up @@ -258,12 +275,19 @@ class MultiIntBitSet
MultiIntBitSet(const MultiIntBitSet&) noexcept = default;
MultiIntBitSet& operator=(const MultiIntBitSet&) noexcept = default;

void Set(unsigned pos) noexcept { m_val[pos / LIMB_BITS] |= I{1U} << (pos % LIMB_BITS); }
void Add(unsigned pos) noexcept { m_val[pos / LIMB_BITS] |= I{1U} << (pos % LIMB_BITS); }
bool operator[](unsigned pos) const noexcept { return (m_val[pos / LIMB_BITS] >> (pos % LIMB_BITS)) & 1U; }

static MultiIntBitSet Full(unsigned count) noexcept {
MultiIntBitSet ret;
for (unsigned i = 0; i < count; ++i) ret.Set(i);
if (count) {
unsigned i = 0;
while (count > LIMB_BITS) {
ret.m_val[i++] = ~I{0};
count -= LIMB_BITS;
}
ret.m_val[i] = (~I{0}) >> (LIMB_BITS - count);
}
return ret;
}

Expand All @@ -274,22 +298,14 @@ class MultiIntBitSet
return ret;
}

bool None() const noexcept
bool IsEmpty() const noexcept
{
for (auto v : m_val) {
if (v != 0) return false;
}
return true;
}

bool Any() const noexcept
{
for (auto v : m_val) {
if (v != 0) return true;
}
return false;
}

BitPopper Elements() const noexcept { return BitPopper(m_val); }

MultiIntBitSet& operator|=(const MultiIntBitSet& a) noexcept
Expand Down Expand Up @@ -335,7 +351,14 @@ class MultiIntBitSet
return r;
}

friend bool operator<(const MultiIntBitSet& a, const MultiIntBitSet& b) noexcept { return a.m_val < b.m_val; }
friend bool operator>>(const MultiIntBitSet& a, const MultiIntBitSet& b) noexcept
{
for (unsigned i = 0; i < N; ++i) {
if (b.m_val[i] & ~a.m_val[i]) return false;
}
return true;
}

friend bool operator!=(const MultiIntBitSet& a, const MultiIntBitSet& b) noexcept { return a.m_val != b.m_val; }
friend bool operator==(const MultiIntBitSet& a, const MultiIntBitSet& b) noexcept { return a.m_val == b.m_val; }
};
Expand All @@ -361,7 +384,7 @@ class AncestorSets
m_ancestorsets.resize(cluster.size());
for (size_t i = 0; i < cluster.size(); ++i) {
m_ancestorsets[i] = cluster[i].second;
m_ancestorsets[i].Set(i);
m_ancestorsets[i].Add(i);
}

// Propagate
Expand Down Expand Up @@ -399,7 +422,7 @@ class DescendantSets
for (size_t i = 0; i < anc.Size(); ++i) {
auto ancestors{anc[i].Elements()};
while (ancestors) {
m_descendantsets[ancestors.Next()].Set(i);
m_descendantsets[ancestors.Next()].Add(i);
}
}
}
Expand Down Expand Up @@ -498,7 +521,7 @@ struct SortedCluster
S ret;
auto todo{val.Elements()};
while (todo) {
ret.Set(original_to_sorted[todo.Next()]);
ret.Add(original_to_sorted[todo.Next()]);
}
return ret;
}
Expand All @@ -509,7 +532,7 @@ struct SortedCluster
S ret;
auto todo{val.Elements()};
while (todo) {
ret.Set(sorted_to_original[todo.Next()]);
ret.Add(sorted_to_original[todo.Next()]);
}
return ret;
}
Expand Down Expand Up @@ -618,12 +641,12 @@ CandidateSetAnalysis<S> FindBestCandidateSetEfficient(const Cluster<S>& cluster,
}
// Add the transaction to pot/pot_feerate.
pot_feerate += cluster[pos].first;
pot.Set(pos);
pot.Add(pos);
// Update the combined ancestors of pot.
pot_ancestors |= anc[pos];
// If at this point pot covers all its own ancestors, it means pot is topologically
// valid. Perform jump ahead (update inc/inc_feerate to match pot/pot_feerate).
if ((pot_ancestors / pot).None()) {
if (pot >> pot_ancestors) {
inc = pot;
inc_feerate = pot_feerate;
inc_may_be_best = true;
Expand Down Expand Up @@ -651,7 +674,7 @@ CandidateSetAnalysis<S> FindBestCandidateSetEfficient(const Cluster<S>& cluster,

// Only if there are undecided transactions left besides inc and exc actually add it to the
// queue.
if ((all / (inc | exc)).Any()) {
if (!((inc | exc) >> all)) {
queue.emplace_back(inc, exc, inc_feerate, pot_feerate);
ret.max_queue_size = std::max(ret.max_queue_size, queue.size());
}
Expand Down Expand Up @@ -697,7 +720,7 @@ CandidateSetAnalysis<S> FindBestCandidateSetEfficient(const Cluster<S>& cluster,
// concern.
auto new_inc = inc | anc[pos];
auto new_inc_feerate = inc_feerate + ComputeSetFeeRate(cluster, new_inc / inc);
bool may_be_new_best = ((inc & anc[pos]) / done).Any();
bool may_be_new_best = !(done >> (inc & anc[pos]));
add_fn(new_inc, exc, new_inc_feerate, may_be_new_best);
}

Expand All @@ -717,29 +740,29 @@ std::vector<unsigned> LinearizeCluster(const Cluster<S>& cluster)
unsigned left = cluster.size();

// Precompute stuff.
SortedCluster<S> scluster(cluster);
AncestorSets<S> anc(scluster.cluster);
SortedCluster<S> sorted(cluster);
AncestorSets<S> anc(sorted.cluster);
DescendantSets<S> desc(anc);
// Precompute ancestor set sizes, to help with topological sort.
std::vector<unsigned> anccount(cluster.size(), 0);
for (unsigned i = 0; i < cluster.size(); ++i) {
anccount[i] = anc[i].Count();
}
AncestorSetFeerates anc_feerates(scluster.cluster, anc, done);
AncestorSetFeerates anc_feerates(sorted.cluster, anc, done);

// Iterate while there are transactions left.
while (left > 0) {
// Invoke function to find a good/best candidate.
CandidateSetAnalysis<S> analysis;
if (left > 10) {
analysis = FindBestAncestorSet(scluster.cluster, anc, anc_feerates, done);
analysis = FindBestAncestorSet(sorted.cluster, anc, anc_feerates, done);
} else {
analysis = FindBestCandidateSetEfficient(scluster.cluster, anc, desc, anc_feerates, done);
analysis = FindBestCandidateSetEfficient(sorted.cluster, anc, desc, anc_feerates, done);
}

// Sanity checks.
assert(!analysis.best_candidate_set.None()); // Must be at least one transaction
assert((analysis.best_candidate_set & done).None()); // Cannot overlap with processed ones.
assert(!analysis.best_candidate_set.IsEmpty()); // Must be at least one transaction
assert((analysis.best_candidate_set & done).IsEmpty()); // Cannot overlap with processed ones.

// Append candidate's transactions to linearization, and topologically sort them.
size_t old_size = ret.size();
Expand All @@ -757,20 +780,20 @@ std::vector<unsigned> LinearizeCluster(const Cluster<S>& cluster)
if (!left) break; // Bail out quickly if nothing left.
done |= analysis.best_candidate_set;
// Update precomputed ancestor feerates.
anc_feerates.Done(scluster.cluster, desc, analysis.best_candidate_set);
anc_feerates.Done(sorted.cluster, desc, analysis.best_candidate_set);
#if 0
// Verify that precomputed ancestor feerates are correct.
for (unsigned i = 0; i < cluster.size(); ++i) {
if (!done[i]) {
assert(anc_feerates[i] == ComputeSetFeeRate(scluster.cluster, anc[i] / done));
assert(anc_feerates[i] == ComputeSetFeeRate(sorted.cluster, anc[i] / done));
}
}
#endif
}

// Map linearization back from sorted cluster indices to original indices.
for (unsigned i = 0; i < cluster.size(); ++i) {
ret[i] = scluster.sorted_to_original[ret[i]];
ret[i] = sorted.sorted_to_original[ret[i]];
}

return ret;
Expand Down Expand Up @@ -855,9 +878,9 @@ Cluster<S> DeserializeCluster(Span<const unsigned char>& data)
unsigned read = DeserializeNumberBase128(data);
if (read == 0) break;
if (read <= ret.size()) {
parents.Set(ret.size() - read);
parents.Add(ret.size() - read);
} else {
if (read < S::MAX_SIZE) parents.Set(read);
if (read < S::MAX_SIZE) parents.Add(read);
}
}
ret.emplace_back(FeeAndSize{sats, bytes}, std::move(parents));
Expand All @@ -882,11 +905,11 @@ void WeedCluster(Cluster<S>& cluster, const AncestorSets<S>& ancs)
const auto& [_anc_count, idx] = mapping[i];
S parents;
S cover;
cover.Set(idx);
cover.Add(idx);
for (unsigned j = 0; j < i; ++j) {
const auto& [_anc_count_j, idx_j] = mapping[i - 1 - j];
if (ancs[idx][idx_j] && !cover[idx_j]) {
parents.Set(idx_j);
parents.Add(idx_j);
cover |= ancs[idx_j];
}
}
Expand Down Expand Up @@ -915,7 +938,7 @@ Cluster<S> TrimCluster(const Cluster<S>& cluster, const S& done)
while (todo) {
unsigned idx = todo.Next();
if (!done[idx]) {
parents.Set(mapping[idx]);
parents.Add(mapping[idx]);
}
}
ret[i].second = std::move(parents);
Expand Down
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