Re: Non-Commutative calculations in Calc, Revisited

[Jay Belanger]

David Kastrup <dak@gnu.org> writes:

> Jay Belanger <belanger@truman.edu> writes:
>
>> Neon Absentius <absent@sdf.lonestar.org> writes:
>>
>>> When in non-commutative (aka `matrix') mode calc calculates 
>>> (a b)^-1 to be a^-1 b^-1 instead of the correct b^-1 a^-1.
>
> Uh, what's correct about b^-1 a^-1?
>
> Set a=[1,1], b=[1;0], then (a b)^-1 = [1], and neither b^-1 nor a^-1
> exist.
>
> This only works with a and b being square matrices.

Oops; you're right.
Of course, the proper fix will no longer give the general
non-commutative operations that Neon wants to work with.  Perhaps a
square matrix option should be made to the Calc matrix modes.

Jay