OpenQASM support #578

GiggleLiu · 2026-01-11T11:09:19Z

Summary

Add OpenQASM 2.0 parsing and compilation support
Parse OpenQASM files to Yao circuit blocks
Compile Yao circuits to OpenQASM format
Include standard gate library (qelib1.inc)
Add comprehensive tests and documentation

Test plan

Unit tests for parsing
Unit tests for compilation
Documentation with examples

🤖 Generated with Claude Code

- Remove Base.error, use error() directly in parse.jl - Clarify OpenQASM version compatibility in compile.jl docs - Remove [sources] section from YaoToEinsum/Project.toml

The local variable 'error' was shadowing Base.error(), causing 'UndefVarError: error not defined' when trying to throw an error for unknown noise types.

- Use QASM 2.0 compatible syntax for common controlled gates (cx, cy, cz, ch, cu1, crz, ccx) - Change header to OPENQASM 2.0 and include creg declaration - Fix register name from 'reg' to 'q' to match declaration - Add trailing semicolons to all statements - Handle nested ChainBlocks correctly (avoid duplicate semicolons) - Add roundtrip tests for compile->parse->execute equivalence Tested with EasyBuild circuits: qft_circuit, variational_circuit

Apply Optimise.canonicalize to recursively simplify circuits before compiling to OpenQASM. This ensures nested blocks are eliminated and gates are converted to basic types using simplify's fixed-point iteration. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>

Since canonicalize now flattens nested chains automatically, remove the special handling for nested ChainBlocks in print_qasm. Also update docstring and error message to reflect automatic simplification. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>

Copilot

Pull request overview

This PR adds comprehensive OpenQASM 2.0 support to YaoBlocks, enabling bidirectional conversion between Yao quantum circuits and the OpenQASM format. This integration allows users to export Yao circuits for use with other quantum computing frameworks (e.g., Qiskit) and import OpenQASM circuits into Yao for simulation.

Changes:

Added OpenQASM parsing functionality to convert QASM strings/files to YaoBlocks circuits
Implemented OpenQASM compilation to convert YaoBlocks circuits to QASM format
Included comprehensive noise model support for noisy quantum simulations
Added extensive test coverage and user-facing documentation

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
`lib/YaoBlocks/src/YaoBlocks.jl`	Integrates OpenQASM module and exports `qasm` and `parseblock` functions
`lib/YaoBlocks/Project.toml`	Adds OpenQASM package dependency (version 2)
`lib/YaoBlocks/src/openqasm/openqasm.jl`	Module entry point with comprehensive documentation
`lib/YaoBlocks/src/openqasm/compile.jl`	Implements Yao → QASM conversion with support for all common gates
`lib/YaoBlocks/src/openqasm/parse.jl`	Implements QASM → Yao conversion with noise model support
`lib/YaoBlocks/src/openqasm/assets/qelib1.inc`	Standard OpenQASM gate library from Qiskit
`lib/YaoBlocks/test/runtests.jl`	Adds OpenQASM test suite to test runner
`lib/YaoBlocks/test/openqasm/openqasm.jl`	Test suite entry point
`lib/YaoBlocks/test/openqasm/parse.jl`	Comprehensive parsing tests including noise models
`lib/YaoBlocks/test/openqasm/compile.jl`	Compilation tests with round-trip verification
`docs/src/man/openqasm.md`	Extensive user documentation with examples
`docs/make.jl`	Integrates OpenQASM documentation into docs build

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lib/YaoBlocks/src/openqasm/compile.jl

lib/YaoBlocks/src/openqasm/parse.jl

- Fix doctest: update expected Measure output format - Fix typo: "Buiding" -> "Building" - Remove unused current_qubits field from QASMIOContext - Improve qreg/creg duplicate declaration error messages 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>

Test that qft_circuit and variational_circuit can be converted to QASM and parsed back with functional equivalence (verified via fidelity). 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>

- Add QASM compiler support for SWAP, rzz, and PhaseGate (ignored) - Add PutBlock with ControlBlock handler for proper qubit remapping - Add to_basictypes for SqrtX, SqrtY, SqrtW gates (decompose to rotations) - Fix raise_chain to preserve nqubits for empty chains - Skip global phase gates in QASM output - Add rand_google53 roundtrip test for 4 and 8 qubits 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>

- Add section on automatic circuit simplification (canonicalize) - Add roundtrip verification example with EasyBuild circuits - Expand gate tables with SWAP, rzz, and more controlled gates - Organize gates into categories (single-qubit, two-qubit, modifiers) - Add note about QASM 2.0 vs 3.0 compatibility - Add section on interoperability with Cirq and PennyLane - Add limitations section documenting known constraints 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>

GiggleLiu · 2026-01-11T16:13:25Z

@Roger-luo This PR made OpenQASM a feasture of YaoBlocks. Round trip tests on variational circuit, qft circuit and google supremacy circuits all pass.

Copilot has reviewed this PR. Let me know if you agree this PR can be merged in its current status?

Copilot

Pull request overview

Copilot reviewed 16 out of 16 changed files in this pull request and generated 2 comments.

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src/EasyBuild/block_extension/shortcuts.jl

lib/YaoBlocks/ext/OpenQASMExt/compile.jl

Clarify that SqrtX = exp(iπ/4) * Rx(π/2) and SqrtY = exp(iπ/4) * Ry(π/2), explaining that global phase doesn't affect measurement outcomes or fidelity. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>

The control gate printing logic was duplicated between PutBlock{ControlBlock} and ControlBlock handlers. Extract shared logic into print_control_gate helper. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>

Roger-luo · 2026-01-12T04:47:47Z

can we make this optional? or an extra dependency? I'm concerned this is a bad start of adding a bunch of parser or parser generator dependencies into the core package YaoBlocks.

GiggleLiu · 2026-01-22T07:32:17Z

I agree. QASM is implemented by pirating, seems no easy ways to fix.

OpenQASM is now a weak dependency that gets activated when users load the OpenQASM package. This addresses the concern about adding parser dependencies to the core YaoBlocks package. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>

The OpenQASM support was moved to a package extension, but the test/easybuild/openqasm.jl tests didn't load the OpenQASM package, causing MethodError failures in CI. Co-Authored-By: Claude Opus 4.5 <[email protected]>

GiggleLiu · 2026-01-24T07:27:39Z

@Roger-luo OpenQASM has been made a package extension (weak dependency) of YaoBlocks — it is not a direct dependency of either YaoBlocks or Yao. Users only get the qasm/parseblock functionality when they explicitly using OpenQASM.

The setup:

lib/YaoBlocks/Project.toml: OpenQASM is listed under [weakdeps] and [extensions], not [deps]
The implementation lives in lib/YaoBlocks/ext/OpenQASMExt/
YaoBlocks.jl only defines stub functions (function qasm end, function parseblock end)
No parser dependencies are pulled into the core package

The CI failure has been fixed — the Yao-level test file was missing using OpenQASM to trigger the extension.

GiggleLiu and others added 6 commits January 11, 2026 19:04

openqasm support

91f6fe8

address Copilot review comments for OpenQASM

56568fb

- Remove Base.error, use error() directly in parse.jl - Clarify OpenQASM version compatibility in compile.jl docs - Remove [sources] section from YaoToEinsum/Project.toml

fix: rename error variable to err to avoid shadowing Base.error

1c2fc21

The local variable 'error' was shadowing Base.error(), causing 'UndefVarError: error not defined' when trying to throw an error for unknown noise types.

GiggleLiu requested a review from Copilot January 11, 2026 13:32

Copilot started reviewing on behalf of GiggleLiu January 11, 2026 13:32 View session

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GiggleLiu and others added 3 commits January 11, 2026 21:48

GiggleLiu mentioned this pull request Jan 11, 2026

Consider using canonicalize consistently before circuit conversions #579

Open

GiggleLiu requested a review from Copilot January 11, 2026 16:08

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GiggleLiu requested a review from Roger-luo January 11, 2026 16:13

GiggleLiu and others added 2 commits January 12, 2026 00:16

GiggleLiu and others added 2 commits January 22, 2026 20:06

Fix Yao test: load OpenQASM extension before calling qasm/parseblock

e157003

The OpenQASM support was moved to a package extension, but the test/easybuild/openqasm.jl tests didn't load the OpenQASM package, causing MethodError failures in CI. Co-Authored-By: Claude Opus 4.5 <[email protected]>

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GiggleLiu commented Jan 11, 2026

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