The Sinus Cardinal family of functions (indexed by the family of indices a > 0) is defined by

it sees heavy use in signal processing tasks.

By analogy, the Hyperbolic Sinus Cardinal family of functions (also indexed by the family of indices a > 0) is defined by

These two families of functions are composed of entire functions.

These functions (sinc_pi and sinhc_pi) are needed by our implementation of quaternions and octonions.