  QuOp_MPI is a Python package designed for parallel simulation of quantum
variational algorithms. It presents an object-orientated approach to quantum
variational algorithm design and utilises MPI-parallelised sparse-matrix
exponentiation, the fast Fourier transform and parallel gradient evaluation to
achieve the highly efficient simulation of the fundamental unitary dynamics on
massively parallel systems. In this article, we introduce QuOp_MPI and explore
its application to the simulation of quantum algorithms designed to solve
combinatorial optimisation algorithms including the Quantum Approximation
Optimisation Algorithm, the Quantum Alternating Operator Ansatz, and the
Quantum Walk-assisted Optimisation Algorithm.
