What's New in v3.25

Connected Blocks (Experimental)

KaFFPa and KaFFPaE now support --connected_blocks (strong preconfiguration only) to produce partitions where each block is a connected subgraph.

Usage:

./deploy/kaffpa graph.graph --k 4 --preconfiguration=strong --connected_blocks

Details:

• The input graph must be connected; a warning is printed for disconnected graphs.
• Only supported with --preconfiguration=strong. Other preconfigurations will print an error.
• Connectivity is enforced via checkpoint-based component elimination during uncoarsening, combined with connectivity-aware refinement and greedy rebalancing.
• When --connected_blocks is not used, KaHIP behavior is completely unchanged (identical cuts and running times).

64-bit Edge Support

The C interface now supports 64-bit edges via a compile-time kahip_idx typedef (int64_t or int32_t). Compile with -D64BITMODE=On to enable.

Changes

• All edge-related CSR arrays (xadj, adjncy, adjcwgt) and edge-valued outputs (edgecut, infinity_edge_weight) use kahip_idx in the public C interface
• Internal EdgeID and EdgeWeight become signed int64_t in 64-bit mode
• UNSAFE_metis_style methods return kahip_idx*
• MPI broadcast uses conditional MPI_INT64_T/MPI_INT types
• Node-related parameters (n, vwgt, nparts, part) remain int
• Added kahip_sizeof_idx() to query index width at runtime (returns 4 or 8)

Windows Support

• KaHIP now builds on Windows with MSVC (no MPI, library + interface only)
• Added Windows CI workflow via GitHub Actions
• Platform guards for POSIX-specific headers (regex.h, sys/mman.h, execinfo.h)
• Windows pip wheels now available on PyPI (Python 3.9-3.14)

pkg-config Support

• KaHIP and ParHIP are now discoverable via pkg-config (merged PR #134)

Build & CI

• Updated cibuildwheel to v3.4.0, GitHub Actions to v5 with Node.js 24
• Added Python 3.13 and 3.14 wheel builds, dropped EOL Python 3.8

Bug Fixes

• Fixed type mismatch in tabu_moves_queue.h (declaration vs definition of minValue)
• Fixed edge_evaluator.cpp using EdgeID instead of PartitionID for partition vectors
• Fixed CMake target_compile_definitions syntax (merged PR #135)

KaHIP v3.23

What's New

• Homebrew support: brew install KaHIP/kahip/kahip
• Updated README with logo, expanded badges (arXiv, platform, CI, university)
• Updated references to latest journal versions (ACM JEA 2020 for ILP and process mapping, ALENEX 2021 for node ordering)
• Added missing citations for mt-KaHIP (IEEE TPDS 2020) and hierarchical process mapping (SEA 2020)

Install

Homebrew:

brew install KaHIP/kahip/kahip

Python:

pip install kahip

From source:

git clone https://github.com/KaHIP/KaHIP && cd KaHIP
./compile_withcmake.sh

• support for PyPi, e.g. pip install kahip, and then use KaHIP in Python
• minor fixes

fixed tag

minor changes

Mainly bug fixes and update of node ordering routine.

Minor update with bugfixes etc...

Added a version option to all KaHIP programs.