Quick start: shortest paths

Make epsilon explicit

A hopset is not a magic speedup switch. The useful contract is that the approximation budget is visible at the call site and checked against a baseline for the workload.

from reachq import WeightedDigraph
from reachq.hopset import build_hopset_for_sssp
from reachq.invariants import assert_distance_approximation

graph = WeightedDigraph()
graph.add_edge("a", "b", 1)
graph.add_edge("b", "c", 2)
graph.add_edge("a", "c", 10)
hopset, beta = build_hopset_for_sssp(graph, epsilon=0.1, random_seed=42)
assert_distance_approximation(
    graph, hopset, source="a", epsilon=0.1, max_hops=20,
)

The current implementation is sequential. See the benchmark guidance for what to record.