  We introduce a distributed classical simulation algorithm for general quantum
circuits, and present numerical results for calculating the output
probabilities of universal random circuits. We find that we can simulate more
qubits to greater depth than previously reported using the cluster supported by
the Data Infrastructure and Search Technology Division of the Alibaba Group.
For example, computing a single amplitude of an $8\times 8$ qubit circuit with
depth $40$ was previously beyond the reach of supercomputers. Our algorithm can
compute this within $2$ minutes using a small portion ($\approx$ 14% of the
nodes) of the cluster.
  Furthermore, by successfully simulating quantum supremacy circuits of size
$9\times 9\times 40$, $10\times 10\times 35 $, $11\times 11\times 31$, and
$12\times 12\times 27 $, we give evidence that noisy random circuits with
realistic physical parameters may be simulated classically. This suggests that
either harder circuits or error-correction may be vital for achieving quantum
supremacy from random circuit sampling.
