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🐛 update edge counts efficiently
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@wolfram77
wolfram77 committed Feb 12, 2025
1 parent 5bc21a7 commit bc38925
Showing 1 changed file with 88 additions and 37 deletions.
125 changes: 88 additions & 37 deletions inc/Graph.hxx
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Original file line number Diff line number Diff line change
Expand Up @@ -134,6 +134,24 @@ class ArenaDiGraph {
inline bool directed() const noexcept {
return true;
}

/**
* Set the number of vertices in the graph.
* @param n new number of vertices
* @note This is used for internal purposes only.
*/
inline void setOrder(size_t n) noexcept {
N = n;
}

/**
* Set the number of edges in the graph.
* @param m new number of edges
* @note This is used for internal purposes only.
*/
inline void setSize(size_t m) noexcept {
M = m;
}
#pragma endregion


Expand Down Expand Up @@ -793,13 +811,15 @@ class ArenaDiGraph {
* @param ie end iterator of edge keys to remove
* @param fl comparison function for edge keys
* @note [ib, ie) must be sorted and unique.
* @returns number of edges removed
*/
template <class I, class FL>
inline void removeEdges(K u, I ib, I ie, FL fl) {
if (!hasVertex(u)) return;
inline size_t removeEdges(K u, I ib, I ie, FL fl) {
if (!hasVertex(u)) return 0;
auto *eb = edges[u], *ee = edges[u] + degrees[u];
auto it = set_difference(eb, ee, ib, ie, eb, fl);
degrees[u] = it - eb;
return ee - it;
}


Expand All @@ -809,11 +829,12 @@ class ArenaDiGraph {
* @param ib begin iterator of edge keys to remove
* @param ie end iterator of edge keys to remove
* @note [ib, ie) must be sorted and unique.
* @returns number of edges removed
*/
template <class I>
inline void removeEdges(K u, I ib, I ie) {
inline size_t removeEdges(K u, I ib, I ie) {
auto fl = [](const auto& a, const auto& b) { return a.first < b; };
removeEdges(u, ib, ie, fl);
return removeEdges(u, ib, ie, fl);
}


Expand All @@ -823,10 +844,11 @@ class ArenaDiGraph {
* @param ib begin iterator of edges to add
* @param ie end iterator of edges to add
* @note [ib, ie) must be sorted and unique.
* @returns number of edges added
*/
template <class I>
inline void addEdges(K u, I ib, I ie) {
if (!hasVertex(u) || ib==ie) return;
inline size_t addEdges(K u, I ib, I ie) {
if (!hasVertex(u) || ib==ie) return 0;
auto *eb = edges[u], *ee = edges[u] + degrees[u];
size_t deg = degrees[u] + distance(ib, ie);
size_t cap = allocationCapacity(deg);
Expand All @@ -837,6 +859,7 @@ class ArenaDiGraph {
edges[u] = ptr;
degrees[u] = it - ptr;
capacities[u] = cap;
return (it - ptr) - (ee - eb);
}


Expand Down Expand Up @@ -1559,36 +1582,43 @@ class DiGraphCsr {
* Subtract a graph's edges from another graph.
* @param a graph to subtract from (updated)
* @param y graph to subtract
* @returns number of edges removed
*/
template <class H, class G>
inline void subtractGraphEdgesU(H& a, const G& y) {
inline size_t subtractGraphEdgesU(H& a, const G& y) {
size_t dM = 0;
y.forEachVertexKey([&](auto u) {
if (!a.hasVertex(u)) return;
auto yb = y.beginEdges(u), ye = y.endEdges(u);
auto fl = [](const auto& a, const auto& b) { return a.first < b.first; };
a.removeEdges(u, yb, ye, fl);
dM += a.removeEdges(u, yb, ye, fl);
});
a.update(true, true);
// Update the number of edges.
a.setSize(a.size() - dM);
return dM;
}


/**
* Subtract a graph's edges from another graph [parallel].
* @param a graph to subtract from (updated)
* @param y graph to subtract
* @returns number of edges removed
*/
template <int CHUNK=1024, class H, class G>
inline void subtractGraphOmpU(H& a, const G& y) {
inline size_t subtractGraphOmpU(H& a, const G& y) {
using K = typename H::key_type;
size_t S = y.span();
#pragma omp parallel for schedule(dynamic, CHUNK)
size_t S = y.span(), dM = 0;
#pragma omp parallel for schedule(dynamic, CHUNK) reduction(+:dM)
for (K u=0; u<S; ++u) {
if (!y.hasVertex(u) || !a.hasVertex(u)) continue;
auto yb = y.beginEdges(u), ye = y.endEdges(u);
auto fl = [](const auto& a, const auto& b) { return a.first < b.first; };
a.removeEdges(u, yb, ye, fl);
dM += a.removeEdges(u, yb, ye, fl);
}
a.updateOmp(true, true);
// Update the number of edges.
a.setSize(a.size() - dM);
return dM;
}


Expand All @@ -1597,10 +1627,11 @@ inline void subtractGraphOmpU(H& a, const G& y) {
* @param a output graph (output)
* @param x graph to subtract from
* @param y graph to subtract
* @returns number of edges removed
*/
template <class H, class GX, class GY>
inline void subtractGraphW(H& a, const GX& x, const GY& y) {
size_t S = x.span();
inline size_t subtractGraphW(H& a, const GX& x, const GY& y) {
size_t S = x.span(), dM = 0;
a.clear();
a.reserve(S);
// Add the vertices.
Expand Down Expand Up @@ -1628,8 +1659,11 @@ inline void subtractGraphW(H& a, const GX& x, const GY& y) {
auto fl = [](const auto& a, const auto& b) { return a.first < b.first; };
auto it = set_difference(xb, xe, yb, ye, ab, fl);
a.setDegreeUnsafe(u, it - ab);
dM += (xe - xb) - (it - ab);
});
// Update the number of edges.
a.update(true, true);
return dM;
}


Expand All @@ -1639,11 +1673,12 @@ inline void subtractGraphW(H& a, const GX& x, const GY& y) {
* @param a output graph (output)
* @param x graph to subtract from
* @param y graph to subtract
* @returns number of edges removed
*/
template <int CHUNK=1024, class H, class GX, class GY>
inline void subtractGraphOmpW(H& a, const GX& x, const GY& y) {
inline size_t subtractGraphOmpW(H& a, const GX& x, const GY& y) {
using K = typename H::key_type;
size_t S = x.span();
size_t S = x.span(), dM = 0;
a.clearOmp();
a.reserveOmp(S);
// Add the vertices.
Expand All @@ -1668,7 +1703,7 @@ inline void subtractGraphOmpW(H& a, const GX& x, const GY& y) {
a.setDegreeUnsafe(u, it - ab);
}
// Now add edges of vertices that are touched.
#pragma omp parallel for schedule(dynamic, CHUNK)
#pragma omp parallel for schedule(dynamic, CHUNK) reduction(+:dM)
for (K u=0; u<S; ++u) {
if (!x.hasVertex(u) || !y.hasVertex(u)) continue;
auto xb = x.beginEdges(u), xe = x.endEdges(u);
Expand All @@ -1677,8 +1712,11 @@ inline void subtractGraphOmpW(H& a, const GX& x, const GY& y) {
auto fl = [](const auto& a, const auto& b) { return a.first < b.first; };
auto it = set_difference(xb, xe, yb, ye, ab, fl);
a.setDegreeUnsafe(u, it - ab);
dM += (xe - xb) - (it - ab);
}
// Update the number of edges.
a.updateOmp(true, true);
return dM;
}
#endif

Expand All @@ -1687,11 +1725,12 @@ inline void subtractGraphOmpW(H& a, const GX& x, const GY& y) {
* Add a graph's edges to another graph.
* @param a graph to add to (updated)
* @param y graph to add
* @returns number of edges added
*/
template <class H, class G>
inline void addGraphU(H& a, const G& y) {
size_t A = a.span(), Y = y.span();
size_t S = max(A, Y);
inline size_t addGraphU(H& a, const G& y) {
size_t A = a.span(), Y = y.span();
size_t S = max(A, Y), dM = 0;
if (S!=A) a.respan(S);
// Add new vertices.
y.forEachVertex([&](auto u, auto d) {
Expand All @@ -1700,9 +1739,11 @@ inline void addGraphU(H& a, const G& y) {
// Add new edges.
y.forEachVertex([&](auto u, auto d) {
auto yb = y.beginEdges(u), ye = y.endEdges(u);
a.addEdges(u, yb, ye);
dM += a.addEdges(u, yb, ye);
});
a.update(true, true);
// Update the number of edges.
a.setSize(a.size() + dM);
return dM;
}


Expand All @@ -1711,12 +1752,13 @@ inline void addGraphU(H& a, const G& y) {
* Add a graph's edges to another graph [parallel].
* @param a graph to add to (updated)
* @param y graph to add
* @returns number of edges added
*/
template <int CHUNK=512, class H, class G>
inline void addGraphOmpU(H& a, const G& y) {
inline size_t addGraphOmpU(H& a, const G& y) {
using K = typename H::key_type;
size_t A = a.span(), Y = y.span();
size_t S = max(A, Y);
size_t A = a.span(), Y = y.span();
size_t S = max(A, Y), dM = 0;
if (S!=A) a.respan(S);
// Add new vertices.
#pragma omp parallel for schedule(static, 2048)
Expand All @@ -1725,13 +1767,15 @@ inline void addGraphOmpU(H& a, const G& y) {
a.addVertex(u, y.vertexValue(u));
}
// Add new edges.
#pragma omp parallel for schedule(dynamic, CHUNK)
#pragma omp parallel for schedule(dynamic, CHUNK) reduction(+:dM)
for (K u=0; u<Y; ++u) {
if (!y.hasVertex(u)) continue;
auto yb = y.beginEdges(u), ye = y.endEdges(u);
a.addEdges(u, yb, ye);
dM += a.addEdges(u, yb, ye);
}
a.updateOmp(true, true);
// Update the number of edges.
a.setSize(a.size() + dM);
return dM;
}
#endif

Expand All @@ -1741,12 +1785,13 @@ inline void addGraphOmpU(H& a, const G& y) {
* @param a output graph (output)
* @param x graph to add from
* @param y graph to add
* @returns number of edges added
*/
template <class H, class GX, class GY>
inline void addGraphW(H& a, const GX& x, const GY& y) {
inline size_t addGraphW(H& a, const GX& x, const GY& y) {
using K = typename H::key_type;
size_t X = x.span(), Y = y.span();
size_t S = max(X, Y);
size_t X = x.span(), Y = y.span();
size_t S = max(X, Y), dM = 0;
a.clear();
a.reserve(S);
// Add the vertices.
Expand All @@ -1766,8 +1811,11 @@ inline void addGraphW(H& a, const GX& x, const GY& y) {
auto fl = [](const auto& a, const auto& b) { return a.first < b.first; };
auto it = set_union(xb, xe, yb, ye, ab, fl);
a.setDegreeUnsafe(u, it - ab);
dM += (it - ab) - (xe - xb);
}
// Update the number of edges.
a.update(true, true);
return dM;
}


Expand All @@ -1779,10 +1827,10 @@ inline void addGraphW(H& a, const GX& x, const GY& y) {
* @param y graph to add
*/
template <int CHUNK=512, class H, class GX, class GY>
inline void addGraphOmpW(H& a, const GX& x, const GY& y) {
inline size_t addGraphOmpW(H& a, const GX& x, const GY& y) {
using K = typename H::key_type;
size_t X = x.span(), Y = y.span();
size_t S = max(X, Y);
size_t X = x.span(), Y = y.span();
size_t S = max(X, Y), dM = 0;
a.clearOmp();
a.reserveOmp(S);
// Add the vertices.
Expand All @@ -1798,7 +1846,7 @@ inline void addGraphOmpW(H& a, const GX& x, const GY& y) {
a.allocateEdges(u, x.degree(u) + y.degree(u));
}
// Now add edges of vertices that are touched.
#pragma omp parallel for schedule(dynamic, CHUNK)
#pragma omp parallel for schedule(dynamic, CHUNK) reduction(+:dM)
for (K u=0; u<S; ++u) {
if (!x.hasVertex(u) && !y.hasVertex(u)) continue;
auto xb = x.beginEdges(u), xe = x.endEdges(u);
Expand All @@ -1807,8 +1855,11 @@ inline void addGraphOmpW(H& a, const GX& x, const GY& y) {
auto fl = [](const auto& a, const auto& b) { return a.first < b.first; };
auto it = set_union(xb, xe, yb, ye, ab, fl);
a.setDegreeUnsafe(u, it - ab);
dM += (it - ab) - (xe - xb);
}
// Update the number of edges.
a.updateOmp(true, true);
return dM;
}
#endif
#pragma endregion
Expand Down

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