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 Submitted by : (unknown) at: 2007-11-17T22:02:51-08:00 (11 years ago) Name : Axiom Version : default friCAS-20090114 Axiom-20050901 OpenAxiom-20091012 OpenAxiom-20110220 OpenAxiom-Release-141 Category : Axiom Aldor Interface Axiom Compiler Axiom Library Axiom Interpreter Axiom Documentation Axiom User Interface building Axiom from source lisp system MathAction Doyen CD Reduce Axiom on Windows Axiom on Linux Severity : critical serious normal minor wishlist Status : open closed rejected not reproducible fix proposed fixed somewhere duplicate need more info Optional subject :   Optional comment :

axiom
p := -x*y^2+x*y+x^3-x^2 (1)
Type: Polynomial(Integer)
axiom
)se ou algebra on
D(factor(p),x)
2         2
(2)  - (y  - y - 3x  + 2x) (2)
Type: Factored(Polynomial(Integer))
axiom
D(p,x)
2         2
(3)  - y  + y + 3x  - 2x (3)
Type: Polynomial(Integer)

Note that the factorization is correct. It's the D(.,x) that misses the sign.

Forgot to categorize... --unknown, Mon, 20 Jun 2005 10:18:00 -0500 reply
Category: Axiom Compiler => Axiom Mathematics Severity: normal => serious

Severity: serious => critical Status: open => fix proposed

The mistake is in differentiate\$FR which currently reads:
    differentiate(u:%, deriv: R -> R) ==
ans := deriv(unit u) * ((u exquo (fr := unit(u)::%))::%)
ans + fr * (_+/[fact.xpnt * deriv(fact.fctr) *
((u exquo nilFactor(fact.fctr, 1))::%) for fact in factorList u])


It intends to use the formula where Therefore, the fix is to leave away the 'fr':

    differentiate(u:%, deriv: R -> R) ==
ans := deriv(unit u) * ((u exquo unit(u)::%)::%)
ans + (_+/[fact.xpnt * deriv(fact.fctr) *
((u exquo nilFactor(fact.fctr, 1))::%) for fact in factorList u])


Martin

applied in patch-41 --kratt6, Tue, 04 Oct 2005 05:51:35 -0500 reply
Status: fix proposed => closed

Category: Axiom Mathematics => Axiom Library

unfortunately, TeX output misses a parenthesis. See Issue #95

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