  We introduce JuliQAOA, a simulation package specifically built for the
Quantum Alternating Operator Ansatz (QAOA). JuliQAOA does not require a
circuit-level description of QAOA problems, or another package to simulate such
circuits, instead relying on a more direct linear algebra implementation. This
allows for increased QAOA-specific performance improvements, as well as
improved flexibility and generality. JuliQAOA is the first QAOA package
designed to aid in the study of both constrained and unconstrained
combinatorial optimization problems, and can easily include novel cost
functions, mixer Hamiltonians, and other variations. JuliQAOA also includes
robust and extensible methods for learning optimal angles. Written in the Julia
language, JuliQAOA outperforms existing QAOA software packages and scales well
to HPC-level resources. JuliQAOA is available at
https://github.com/lanl/JuliQAOA.jl.
