Dear all,
if we define A to be
A = matrix([[1,-3,0,2],[-2,4,0,h],[0,-2,1,k],[3,-1,7,1]])
A.echelon_form()
gives diag(1,1,1,1). But this is wrong for some values of h and k.In some cases the last 1 could be 0.
How can I fix this? Thanks, N
I'm not sure why this does not work over the symbolic ring, but it does so over the rational field of polynomials in h and k:
R.<h,k> = PolynomialRing(QQ,2)
A = matrix([[1,-3,0,2],[-2,4,0,h],[0,-2,1,k],[3,-1,7,1]])
A.echelon_form()
gives
[ 1 0 0 -3/2*h - 4]
[ 0 1 0 -1/2*h - 2]
[ 0 0 1 -h + k - 4]
[ 0 0 0 11*h - 7*k + 39]
ADDED. Explanation for why this does not work over SR is given in this answer.
Asked: 2023-09-07 07:03:34 +0100
Seen: 219 times
Last updated: Sep 12 '23
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A possible approach would be defining a function of
handk.Sorry not clear enough for me … What do you mean?
Like this:
I see. Thanks. But in this case I have to enter the values for h and k. That's not what I want... I'd like Sage to tell me what condition on h and k gives an echelon form like drag(1,1,1,1) and which one gives drag(1,1,1,0).
diag not drag :-)