maxima is off by -1 with its charpoly

[mwhansen]

sage: matrix(SR, 5, [1..5^2]).charpoly().expand()
-x^5 + 65*x^4 + 250*x^3
sage: matrix(QQ, 5, [1..5^2]).charpoly()
x^5 - 65*x^4 - 250*x^3

Component: calculus

Issue created by migration from https://trac.sagemath.org/ticket/2036

[jasongrout]

comment:2

Maxima defines the charpoly as:

determinant (M - diagmatrix (length (M), x))

See http://maxima.sourceforge.net/docs/manual/en/maxima_25.html#SEC81

[williamstein]

comment:3

That's a nonstandard definition so we have to work around it.

William

[jasongrout]

Attachment: maxima-charpoly.patch.gz

[mwhansen]

comment:5

Looks good to me.

[sagetrac-mabshoff]

comment:6

Merged in Sage 2.10.2.alpha0