[Maxima-bugs] [ maxima-Bugs-696818 ] Taylor internal error (rat problem?)

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Bugs item #696818, was opened at 2003-03-03 15:15
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Category: None
Group: None
Status: Open
Resolution: None
>Priority: 6
Submitted By: Stavros Macrakis (macrakis)
Assigned to: Nobody/Anonymous (nobody)
Summary: Taylor internal error (rat problem?)

Initial Comment:
taylor(asin(sin(x)+e),x,0,2) =>
Quotient by a polynomial of higher degree

taylor(log(sqrt(e*%e^x+1)+e),x,0,2) =>
Quotient by a polynomial of higher degree

Maxima version: 5.9.0
Maxima build date: 19:10 2/9/2003
host type: i686-pc-mingw32
lisp-implementation-type: Kyoto Common Lisp
lisp-implementation-version: GCL-2-5.0

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>Comment By: Stavros Macrakis (macrakis)
Date: 2003-03-03 16:51

Message:
Logged In: YES 
user_id=588346

Fateman suggested:

> Sometimes changing the GCD algorithm to one without
> a bug in it helps.  gcd:subres for example.

Thanks for the tip.  Here are results with the different GCD 
algorithms.  Subres/oldgcd is the default in 5.9.0, though the 
documentation says the default is Spmod/zgcd.  The doc 
also claims that subres is the "new algorithm", though 
internally, confusingly, the Subres option calls oldgcd; has 
the mapping between names and functions changed?

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taylor(asin(sin(x)+e),x,0,2),gcd:XXX;

EZ      OK =ezgcd2
SPMOD   OK =zgcd
FALSE   OK
MOD     OK =newgcd (MOD option in code, not documented)

SUBRES  error =oldgcd
RED     error =oldgcd

EEZ     "EEZGCD is invalid as a function"
SPHEN   "SPHGCD is invalid as a function" (SPHEN option 
in code, not documented)


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