  This work considers the coded caching problem with shared caches, where users
share the caches, and each user gets access only to one cache. The
user-to-cache association is assumed to be known at the server during the
placement phase. We focus on the schemes derived using placement delivery
arrays (PDAs). The PDAs were originally designed to address the
sub-packetization bottleneck of coded caching in a dedicated cache setup. We
observe that in the setup of this paper permuting the columns of the PDA
results in schemes with different performance for the same problem, but the
sub-packetization level remains the same. This is contrary to what was observed
for dedicated cache networks. We propose a procedure to identify the ordering
of columns that gives the best performance possible for the PDA employed for
the given problem. Further, some specific classes of PDAs are chosen and the
performance gain achieved by reordering the columns of the PDA is illustrated.
