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32548cf02b
Changelog-EXPERIMENTAL: askrene new graph abstraction Signed-off-by: Lagrang3 <lagrang3@protonmail.com>
79 lines
2.4 KiB
C
79 lines
2.4 KiB
C
#include "config.h"
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#include <plugins/askrene/graph.h>
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/* in the background add the actual arc or dual arc */
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static void graph_push_outbound_arc(struct graph *graph, const struct arc arc,
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const struct node node)
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{
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assert(arc.idx < tal_count(graph->arc_tail));
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/* arc is already added, skip */
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if (graph->arc_tail[arc.idx].idx != INVALID_INDEX)
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return;
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graph->arc_tail[arc.idx] = node;
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assert(node.idx < tal_count(graph->node_adjacency_first));
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const struct arc first_arc = graph->node_adjacency_first[node.idx];
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assert(arc.idx < tal_count(graph->node_adjacency_next));
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graph->node_adjacency_next[arc.idx] = first_arc;
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assert(node.idx < tal_count(graph->node_adjacency_first));
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graph->node_adjacency_first[node.idx] = arc;
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}
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bool graph_add_arc(struct graph *graph, const struct arc arc,
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const struct node from, const struct node to)
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{
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assert(from.idx < graph->max_num_nodes);
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assert(to.idx < graph->max_num_nodes);
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const struct arc dual = arc_dual(graph, arc);
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if (arc.idx >= graph->max_num_arcs || dual.idx >= graph->max_num_arcs)
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return false;
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graph_push_outbound_arc(graph, arc, from);
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graph_push_outbound_arc(graph, dual, to);
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return true;
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}
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struct graph *graph_new(const tal_t *ctx, const size_t max_num_nodes,
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const size_t max_num_arcs, const size_t arc_dual_bit)
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{
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struct graph *graph;
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graph = tal(ctx, struct graph);
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/* bad allocation of graph */
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if (!graph)
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return graph;
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graph->max_num_arcs = max_num_arcs;
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graph->max_num_nodes = max_num_nodes;
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graph->arc_dual_bit = arc_dual_bit;
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graph->arc_tail = tal_arr(graph, struct node, graph->max_num_arcs);
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graph->node_adjacency_first =
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tal_arr(graph, struct arc, graph->max_num_nodes);
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graph->node_adjacency_next =
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tal_arr(graph, struct arc, graph->max_num_arcs);
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/* bad allocation of graph components */
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if (!graph->arc_tail || !graph->node_adjacency_first ||
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!graph->node_adjacency_next) {
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return tal_free(graph);
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}
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/* initialize with invalid indexes so that we know these slots have
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* never been used, eg. arc/node is newly created */
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for (size_t i = 0; i < graph->max_num_arcs; i++)
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graph->arc_tail[i] = node_obj(INVALID_INDEX);
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for (size_t i = 0; i < graph->max_num_nodes; i++)
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graph->node_adjacency_first[i] = arc_obj(INVALID_INDEX);
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for (size_t i = 0; i < graph->max_num_nodes; i++)
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graph->node_adjacency_next[i] = arc_obj(INVALID_INDEX);
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return graph;
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}
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