PennyLane Catalyst

Catalyst is an experimental package for just-in-time (JIT) compilation of hybrid quantum-classical programs within PennyLane. It allows you to compile the entire workflow, including optimization loops, directly from Python using the @qjit decorator. This integration provides significant performance improvements over standard execution. Key features include:

• Compilation of the full quantum-classical workflow.
• Seamless integration with PennyLane via @qjit.
• Support for advanced control flow combining quantum and classical instructions.
• Infrastructure for compiling both quantum and classical components.
• Built for end-to-end differentiability.
• Support for high-performance simulators and devices.

The core compiler is built on MLIR, lowering to LLVM + QIR. A C++ runtime enables execution on various devices. The Python frontend provides the @qjit decorator and functions for control flow, gradients, and mid-circuit measurements.