Log broken in some cases - may not be log but inv?

[TravisNP]

Error occurs in the last line.
Code to reproduce

using Grassmann
_basis = basis"1,1,1,1"

beta = pi/4
B1 = beta * v1 * v2
rotor1 = exp(B1/2)

gamma = pi/6
B2 = gamma * v3 * v4
rotor2 = exp(B2/2)

rotor = rotor2 * rotor1
B = log(rotor)

Output

inv(1.8924 + 0.369644v₁₂ + 0.0v₁₃ + 0.0v₁₄ + 0.0v₂₃ + 0.0v₂₄ + 0.239118v₃₄ + 0.0990458v₁₂₃₄) is undefined

Stacktrace:
 [1] error(s::String)
   @ Base ./error.jl:35
 [2] inv(m::Spinor{⟨1,1,1,1⟩, Float64, 8})
   @ Grassmann [~/.julia/packages/Grassmann/RyCGA/src/algebra.jl:510](http://localhost:8888/home/pencetn/.julia/packages/Grassmann/RyCGA/src/algebra.jl#line=509)
 [3] [/](http://localhost:8888/)
   @ [~/.julia/packages/AbstractTensors/rjoE8/src/AbstractTensors.jl:320](http://localhost:8888/home/pencetn/.julia/packages/AbstractTensors/rjoE8/src/AbstractTensors.jl#line=319) [inlined]
 [4] log(t::Spinor{⟨1,1,1,1⟩, Float64, 8})
   @ Grassmann [~/.julia/packages/Grassmann/RyCGA/src/composite.jl:370](http://localhost:8888/home/pencetn/.julia/packages/Grassmann/RyCGA/src/composite.jl#line=369)
 [5] top-level scope
   @ In[46]:13

Note this doesn't happen if B1 and B2 share a basis vector (for example B2 = gamma * v2 * v3 works just fine)

[chakravala]

If it says inv(...) is undefined, it means my current multivector inverse algorithm doesn't support inverting that element. I know there are other techniques for inverting multivectors which I have not taken into account yet, but it's not super important for me right now.

Also note that in 4 dimensions, not all multivectors are invertible anymore.

[TravisNP]

Understood, may be more of a feature request then. Thanks!

[chakravala]

This is something I might get around to improving at some point, but probably not in the immediate future. Thanks for reporting.