Compiling and Executing CUDA Quantum Programs

All CUDA Quantum programs must be compiled with the nvq++ compiler. This compiler orchestrates the mapping of quantum kernel expressions to the CUDA Quantum MLIR-based intermediate representation, quantum circuit optimization, placement, and routing, and lowering to LLVM-based representations (e.g. the QIR) for binary object creation and linking. The compiler supports a number of modes, platforms, and target QPU architectures, all of which can be configured with command line flags. All the usual compiler flags provided by compilers like clang++ and gcc are also available for creating hybrid quantum-classical applications and libraries (e.g. linker flags and include header search paths).

Given a CUDA Quantum source file named simple.cpp, one can compile with nvq++ in a similar manner as classical C++ compilers:

nvq++ simple.cpp -o simple.x (optional... -I /header/path -L /library/path -lfoo)
./simple.x

One can specify the QPU architecture to target with the --qpu flag:

nvq++ simple.cpp --qpu cuquantum
./a.out

The cuquantum target QPU will configure the executable to run on GPU-enabled simulation resources accelerated by cuQuantum.

This simple compiler invocation orchestrates a complex workflow that incorporates a number of tools (available in your $CUDA_QUANTUM_PATH/bin directory).

  1. Map CUDA Quantum C++ kernels to Quake MLIR code via Clang ASTConsumers

  2. Register all Quake kernel code with the runtime for quantum IR introspection

  3. Rewrite the original CUDA Quantum C++ kernel entry-point function to invoke an internal runtime kernel launch function which targets the specified quantum_platform

  4. Lower to QIR and link, producing an executable or object code