  To date, quantum computational algorithms have operated on a superposition of
all basis states of a quantum system. Typically, this is because it is assumed
that some function f is known and implementable as a unitary evolution.
However, what if only some points of the function f are known? It then becomes
important to be able to encode only the knowledge that we have about f. This
paper presents an algorithm that requires a polynomial number of elementary
operations for initializing a quantum system to represent only the m known
points of a function f.
