  We have developed a symbolic algebra approach to automatically produce,
verify, and optimize computer code for the Fast Multipole Method (FMM)
operators. This approach allows for flexibility in choosing a basis set and
kernel, and can generate computer code for any expansion order in multiple
languages. The procedure is implemented in the publicly available Python
program Mosaic. Optimizations performed at the symbolic level through algebraic
manipulations significantly reduce the number of mathematical operations
compared with a straightforward implementation of the equations. We find that
the optimizer is able to eliminate 20-80% of the floating-point operations and
for the expansion orders $p \le 10$ it changes the observed scaling properties.
We present our approach using three variants of the operators with the
Cartesian basis set for the harmonic potential kernel $1/r$, including the use
of totally symmetric and traceless multipole tensors.
