Function augment_flow

plugins/askrene/child/algorithm.c:225–259

Augment a `flow` amount along the path defined by `prev`.*/

/* Augment a `flow` amount along the path defined by `prev`.*/
static void augment_flow(const struct graph *graph,
			 const struct node source,
			 const struct node target,
			 const struct arc *prev,
			 s64 *excess,
			 s64 *capacity,
			 s64 flow)
{
	const size_t max_num_nodes = graph_max_num_nodes(graph);
	const size_t max_num_arcs = graph_max_num_arcs(graph);
	assert(max_num_nodes == tal_count(prev));
	assert(max_num_arcs == tal_count(capacity));

	struct node cur = target;
	/* count the number of arcs in the path */
	int path_length = 0;

	while (cur.idx != source.idx) {
		assert(cur.idx < max_num_nodes);
		const struct arc arc = prev[cur.idx];

		sendflow(graph, arc, flow, capacity, excess);

		/* we are traversing in the opposite direction to the flow,
		 * hence the next node is at the tail of the arc. */
		cur = arc_tail(graph, arc);

		/* We may never have a path exceeds the number of nodes, it this
		 * happens it means we have an infinite loop. */
		path_length++;
		if (path_length >= max_num_nodes)
			break;
	}
	assert(path_length < max_num_nodes);
}

bool simple_feasibleflow(const tal_t *ctx,
			 const struct graph *graph,