Apache Mahout Hackathon @ Community over Code Glasgow 2026: Colab notebook, slides and tasks

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Welcome to the Apache Mahout hackathon at Community over Code Glasgow 2026!

• When: Tuesday 13 October, 15:00–18:40
• Where: The Wee Dram Room
• Mentors: Andrew Musselman, Krishna Dave and Mahout committers in the room
• Help: ask a mentor, the #hackathon channel on apachecon.slack.com, or dev@mahout.apache.org

Materials

Colab notebook	Open in Colab · download .ipynb
Kickoff slides	PDF · PPTX
Event page	https://events.apache.org/events/2026/community-over-code/mahout.html

The same content is landing on https://mahout.apache.org/blog via #1513.

Colab setup first (1 minute)

Colab defaults to Python 3.13; Mahout 0.6.0 needs 3.10–3.12.

1. Runtime > Change runtime type
2. Runtime version: 2026.07 (Python 3.12), not "Latest"
3. Hardware accelerator: T4 GPU
4. Save, then Runtime > Run all

Spend at most 10 minutes on Parts 0–3, then pick a task.

Tasks (1–2 hours each, no GPU, each ends in a PR with a test)

Track A: Qumat (Python only)

#	Issue	Task
A1	#1506	Clear ValueError for an unknown backend name
A2	#1507	Unsupported simulator_type should raise instead of print()
A3	#1508	Cirq backend ignores the initialized simulator
A4	#1509	Reusing a parameter name on two gates fails on Qiskit only
A5	#1510	create_empty_circuit() without num_qubits differs per backend
A6	#1511	Add one missing gate per person: S, S†, T†, CZ or Phase
A7	#1512	Python 3.13 support for the qumat package

Track B: QDP (B1–B3 pure Python; B4–B6 Rust, only if you already have cargo, start cargo build right away)

#	Issue	Task
B1	#1469	QdpBenchmark does not validate builder argument ranges
B2	#1331	QDP tests should skip, not error, without a GPU
B3	#1468	File loader ignores the configured batch limit
B4	#1472	Read LZ4-compressed Feather files (Rust)
B5	#787	NumPy file size check to prevent OOM (Rust)
B6	#1436	StreamingProducer: VecDeque for O(1) buffer advance (Rust)

Workflow

git clone https://github.com/<you>/mahout.git && cd mahout
pip install uv
uv sync
uv run pre-commit install
uv run pytest testing/qumat

Comment on the issue to claim it, branch, make the change with a test, open a PR that links the issue, and ping a mentor for the committer approval. Your PR does not have to be finished by 18:40.

Have fun, and thanks for hacking on Apache Mahout!

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Closing this since the context is up on our website already.