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 Submitted by : (unknown) at: 2007-11-17T22:03:19-08:00 (15 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 :

(new) differentiating sums with respect to a bound is wrong --Bill Page, Wed, 22 Jun 2005 13:55:51 -0500 reply
Update of bug #9216 (project axiom):

Status: None => transferred

Example of code trigerring the bug:

axiom
f:=operator 'f
 (1)
Type: BasicOperator?
axiom
D(sum(f(i),i=a..x),x)
>> Error detected within library code:
a sum cannot be differentiated with respect to a bound

is nonsense. The problem is in COMBF/dvdsum:

axiom
dvdsum(l, x) ==
x = retract(y := third l)@SE => 0
k := retract(d := second l)@K
differentiate(h := third rest rest l,x) * eval(f := first l, k, h)
- differentiate(g := third rest l, x) * eval(f, k, g)
+ opdsum [differentiate(f, x), d, y, g, h]
Type: Void

Although this:

is a nice try, it is wrong. It seems that the order of magnitude is roughly correct, but that's about it.

Unfortunately, I do not know how to return the thing unevaluated, so I cannot fix the bug yet

Continued in Bug #180 --kratt6, Thu, 23 Jun 2005 02:18:19 -0500 reply
Category: => Axiom Compiler Severity: => critical Status: => duplicate

 Subject:   Be Bold !! ( 15 subscribers )