As a new Simit user, it would be nice to have more examples, such as the elastic shell simulation presented in the paper.
Thanks!

(#~#^) should be A B^T and vice versa for (#~^#). The documentation and function is above anb below the wrong type signature in each one respectively. Solution is to swap type signatures.

Wrong:

-- | Sparsifying A^T B
(#~#^) :: (MatrixRing (SpMatrix a), Epsilon a) =>
     SpMatrix a -> SpMatrix a -> SpMatrix a
a #~^# b = transpose a #~# b


-- | Sparsifying A B^T
(#~^#) :: (M

That will be much more easier to understand if local axis of the section are coincident with those of the elements by default.

See verif/test/elements/zero_length/test_signo_deformaciones*
and verif/test/elements/beam_column/test_signo_deformaciones01