On Tue, Sep 06, 2005 at 03:03:30PM -0500, Jay Belanger wrote: > > Neon Absentius <[EMAIL PROTECTED]> writes: > > > Sorry if this is not the right list for this question. > > > > Is there a way to suspend some of the automatic simplifications that > > calc performs? In particular I am interested in suspending the > > assumption that multiplication is commutative. > > Does matrix mode ("m v") do what you want?
Yes and no! I mean if it would do what the info describes I would be happy. I don't think that the assumption all variables are matrices really says much more than "distinct variables do not necessarily commute", so that would be exactly what I was looking for. Alas there seems to be a bug: After I give 'm v' if I ask calc to simplify the expression 'a b - b a' it leaves it as is which is as expected. However when I ask it to expand '(a+b)^2' it returns 'a^2 + 2 b a + b^2' which is of course wrong if a and b don't commute. This happens both with emacs-multi-tty (22.0.50) and whith emacs 21.4.1 on a Debian testing/unstable. The bug manifsts itself also for the expansion of '(a+b)^3' however calc expands '(x+y)(x-y)' into 'x^2 + y x - x y + y^2'. Strange! I attach the "Trail buffer" ,---- | Emacs Calculator v2.1 by Dave Gillespie | 1 | alg' (x + y)^2 | simp (x + y)^2 | simp (x + y)^2 | expa x^2 + 2 * y * x + y^2 | derv 2 * x + 2 * y | alg' (a + b)^2 | expa a^2 + 2 * b * a + b^2 | alg' (a + b)^2 | expa a^2 + 2 * b * a + b^2 | alg' (b + a)^2 | expa b^2 + 2 * a * b + a^2 | alg' a | alg' b | alg' b | aprt b | alg' a | * b * a | 3 | alg' a | * b * a | * a * b | - b * a - a * b | simp b * a - a * b | simp b * a - a * b | alg' (b + a)^2 | expa b^2 + 2 * a * b + a^2 | alg' (a + b)^3 | expa a^3 + 3 * b * a^2 + 3 * b^2 * a + b^3 | alg' (x - y) * (x + y) | expa x^2 + x * y - y * x - y^2 | alg' (a - b) * (b + a) | expa a * b + a^2 - b^2 - b * a | alg' a * b | alg' b * a | + a * b + b * a `---- -- Most precious among the relics remaining of Peter's skeleton in the Vatican are 29 fragments of one of his skulls. (St. Peter's other skull is preserved in a reliquary at the Cathedral of St. John Lateran.) -- Frank R. Zindler, "Of Bones and Boners" _______________________________________________ Help-gnu-emacs mailing list Help-gnu-emacs@gnu.org http://lists.gnu.org/mailman/listinfo/help-gnu-emacs