...one of the most highly
regarded and expertly designed C++ library projects in the
world.

— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards

template<typename T> octonion<T> spherical(T const & rho, T const & theta, T const & phi1, T const & phi2, T const & phi3, T const & phi4, T const & phi5, T const & phi6); template<typename T> octonion<T> multipolar(T const & rho1, T const & theta1, T const & rho2, T const & theta2, T const & rho3, T const & theta3, T const & rho4, T const & theta4); template<typename T> octonion<T> cylindrical(T const & r, T const & angle, T const & h1, T const & h2, T const & h3, T const & h4, T const & h5, T const & h6);

These build octonions in a way similar to the way polar builds complex numbers, as there is no strict equivalent to polar coordinates for octonions.

`spherical`

is a simple transposition
of `polar`

, it takes as inputs
a (positive) magnitude and a point on the hypersphere, given by three angles.
The first of these, *theta* has a natural range of -pi to
+pi, and the other two have natural ranges of -pi/2 to +pi/2 (as is the case
with the usual spherical coordinates in * R^{3}*).
Due to the many symmetries and periodicities, nothing untoward happens if the
magnitude is negative or the angles are outside their natural ranges. The expected
degeneracies (a magnitude of zero ignores the angles settings...) do happen
however.

`cylindrical`

is likewise a simple
transposition of the usual cylindrical coordinates in * R^{3}*,
which in turn is another derivative of planar polar coordinates. The first
two inputs are the polar coordinates of the first

`multipolar`

is yet another simple
generalization of polar coordinates. This time, both * C*
components of the octonion are given in polar coordinates.

In this version of our implementation of octonions, there is no analogue of the complex value operation arg as the situation is somewhat more complicated.