I would like to return the result of multiplication in an Iwahori-Hecke algebra not as the element on the right hand side of $$C'_xC'_y=\sum_z h_{x,y,z}C'_z$$
but as a list of pairs $(z, h_{x,y,z})$.
Is this possible? Can this list be created from the usual setup, e.g.
R.<v> = LaurentPolynomialRing(ZZ)
H = IwahoriHeckeAlgebra(['A',2,1], v^2)
W= H.coxeter_group()
s= W.simple_reflections();s
Cp=H.Cp()
Cp.product_on_basis(s[1], s[2]*s[1])
Cp[1,2,1] + Cp[1]
which returns $\sum_z h_{x,y,z}C'_z$?