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#311 Repeated output of the show system command for categories that do not export operations ←	↑	→ #313 sqrt(x,0) should not give 1 in RealClosedField

#312 Bug in sqrt() for UnivariateTaylorSeries

Edit detail for #312 Bug in sqrt() for UnivariateTaylorSeries revision 2 of 2

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Editor: gdr Time: 2008/05/21 02:37:02 GMT-7
Note:

added:

From gdr Wed May 21 02:37:02 -0700 2008
From: gdr
Date: Wed, 21 May 2008 02:37:02 -0700
Subject: 
Message-ID: <20080521023702-0700@axiom-wiki.newsynthesis.org>


Fixed in OpenAxiom

fricas

(1) -> UTSx := UTS(FRAC INT,x,0)

$\label{eq1}\hbox{\axiomType{UnivariateTaylorSeries}\ } \left({{\hbox{\axiomType{Fraction}\ } \left({\hbox{\axiomType{Integer}\ }}\right)}, \: x , \: 0}\right)$

(1)

Type: Type

fricas

monx2 := monomial(1,2)$UTSx

$\label{eq2}{x}^{2}$

(2)

Type: UnivariateTaylorSeries?(Fraction(Integer),x,0)

fricas

sqrt(monx2)

$\label{eq3}x$

(3)

Type: UnivariateTaylorSeries?(Fraction(Integer),x,0)

The last line should of course be and not . Clearly, sqrt() shifts the coefficients of the result such that the leading term is always O(1).

Fix by Igor Khavkine --kratt6, Fri, 27 Oct 2006 03:02:19 -0500 reply

I'm forwarding this fix proposed by Igor himself, lest it is lost in the archives.

The relevant message in axiom-math is

http://lists.gnu.org/archive/html/axiom-math/2006-08/msg00025.html

For simplicity, here is the fix:

  diff -ur axiom-20050901/src/algebra/sttaylor.spad.pamphlet axiom-20050901.new/src/algebra/sttaylor.spad.pamphlet
  --- axiom-20050901/src/algebra/sttaylor.spad.pamphlet 2005-01-30 07:03:10.000000000 -0500
  +++ axiom-20050901.new/src/algebra/sttaylor.spad.pamphlet     2006-08-21 15:49:25.000000000 -0400
  @@ -448,6 +448,9 @@

             RATPOWERS => co**rn * YS(powerrn(rn,(invCo :: A) * x,#1))
             error "** rational power of coefficient undefined"
  +        zeropref : ST A := new(ord::I::NNI,0::A)$LA :: ST A
  +        concat(zeropref, power)
  +

       if A has Field then
         mapdiv(x,y) == delay

If somebody could complete the documentation as outlined in

http://lists.gnu.org/archive/html/axiom-developer/2006-08/msg00486.html

that would be great.

Finally, I have to confess that it is very likely myself who introduced this bug, while fixing #63

Martin

fix by Igor Khavkine --kratt6, Fri, 27 Oct 2006 03:03:15 -0500 reply

Status: open => fix proposed

Here is the documented patch. (Documentation is partially due to Waldek Hebisch)

powern.patch

Martin

... --gdr, Wed, 21 May 2008 02:37:02 -0700 reply

Fixed in OpenAxiom