Mathematica

Here is the method:

1. Ignore all factors of 'i' since quaternions come with i, j, and k pre-installed.
2. Group 4-vectors together. Examples:
• (c t, R)
• (E, P c)
• (d/dt, c d/dR)
3. Keep all constants as a check: c, h, G
4. If possible, make dimensionless
5. Treat the wave function as quaternion-valued (3 complex numbers that share the same real)