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# Edit detail for #294 Infinite recursion during integration revision 8 of 8

 1 2 3 4 5 6 7 8 Editor: test1 Time: 2018/02/08 16:25:29 GMT+0 Note:

added:

From test1 Thu Feb 8 16:25:29 +0000 2018
From: test1
Date: Thu, 08 Feb 2018 16:25:29 +0000
Subject:
Message-ID: <20180208162529+0000@axiom-wiki.newsynthesis.org>

Status: fix proposed => closed



 Submitted by : (unknown) at: 2007-11-17T22:22:32-08:00 (14 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 :

The following input causes infinite recursion in rischNormalize

fricas
integrate(simplify(D((log((x)+1)+a)/(2*((((x*(exp(exp(x)/2)))-(a*(x+exp(-x/2))))*(2/x))-3)), x)), x)
 (1)
Type: Union(Expression(Integer),...)

AFAICS goodCoef chooses to rewrite simpler kernel in terms of a more complex one. More precisely, rischNormalize is supposed to eliminate kernels which are algebraically dependent on other kernels. If a dependent kernel is found rischNormalize should eliminate it and recurse. So the recursion depth is limited by the number of kernels. However, in this example rischNormalize eliminates simpler kernel, but causes new kernels to appear.

elementary integration really should be one of the strengths... --kratt6, Sat, 03 Jun 2006 07:52:55 -0500 reply
Category: Aldor Library Compiler => Axiom Library Severity: normal => serious

Status: open => fix proposed

Status: fix proposed => fixed somewhere

no patch available

From wh-sandbox --alfredo, Thu, 28 Aug 2008 18:46:46 -0700 reply