  We present a scheme for the parallelization of quantum Monte Carlo on
graphical processing units, focusing on bosonic systems and variational Monte
Carlo. We use asynchronous execution schemes with shared memory persistence,
and obtain an excellent acceleration. Comparing with single core execution,
GPU-accelerated code runs over x100 faster. The CUDA code is provided along
with the package that is necessary to execute variational Monte Carlo for a
system representing liquid helium-4. The program was benchmarked on several
models of Nvidia GPU, including Fermi GTX560 and M2090, and the latest Kepler
architecture K20 GPU. Kepler-specific optimization is discussed.
