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Trivial Minimum Cycle Ratio Failing

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
68/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Active
Tech stack
cpp
Domain
data

Research direction

Start with the failing example in commit a56dccbd411acd84f04c64d796b871b4e4bd9598 and the howard_cycle_ratio algorithm, then run the single-self-loop graph from the report. Done means the reproducer reports 6410/2 (3205) instead of +Inf.

Written by the indexing model from the issue text.

Description

Before filing
  • I searched the existing issues and did not find a duplicate.
  • I have reproduced the bug against the develop branch or the latest Boost release.
  • I have a minimal reproducer (or I will paste my full failing code below).
Boost version

1.93 (hash: bf5e43e0850af9381fc880248ebab801e17c41d8)

Compiler family
  • GCC / g++
  • Clang / clang++
  • MSVC (Visual Studio)
  • Intel / oneAPI
  • Other (specify below)

g++ (Ubuntu 13.3.0-6ubuntu2~24.04.1) 13.3.0

Standard library
  • libstdc++
  • libc++ (I am not certain)
  • MSVC STL
  • Other (specify below)
Operating system
  • Linux
  • macOS
  • Windows
  • Other (specify below)
Kind of component affected
  • Graph data structure (e.g. adjacency_list, adjacency_matrix)
  • Algorithm (e.g. dijkstra_shortest_paths, breadth_first_search)
  • Property map
  • I/O or file-format reader (e.g. read_graphml, read_graphviz)
  • Visitor / event hooks
  • Other (specify below)

Affected component: howard_cycle_ratio

Steps to reproduce

Commit a56dccbd411acd84f04c64d796b871b4e4bd9598 in Andful/graph adds the failing example.

The example being:

digraph G {
  a->a  [w1=6410, w2=2];
}

I.e. a single self-loop with cost 6410 and time of 2.

The case originates from a MCR benchmark.

Expected behavior

The minimum cycle ratio should be 6410/2 (i.e. 3205)

Actual behavior

The reported minimum cycle ratio is +Inf

Are you willing to help?
  • I'd like to submit a fix as a pull request.
  • I can help diagnose or test a candidate fix.
  • I'm only reporting the issue.
Dominant language
C++
Stars
396
Forks
244
Avg merge
2d 6h
Merged PRs (30d)
29

Getting set up

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

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