#9891: substitute goes too far: (5-e^x).substitute(x=log(x)) -> 5-log(x)
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Reporter: burcin | Owner: burcin
Type: defect | Status: new
Priority: critical | Milestone: sage-4.6
Component: symbolics | Keywords: pynac
Author: | Upstream: Not yet reported upstream; Will do
shortly.
Reviewer: | Merged:
Work_issues: |
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Reported by Kees on sage-support:
http://groups.google.com/group/sage-support/t/bfa34b077dd31b73
{{{
Running the following few lines:
eq=5-e^x
print "1:",eq.substitute(x=3*x)
print "2:",eq.substitute(x=log(x))
yields the output (Sage 4.5.2 with Ubuntu):
1: -e^(3*x) + 5
2: -log(x) + 5
}}}
This is also present in GiNaC:
{{{
ginsh - GiNaC Interactive Shell (ginac V1.5.7)
__, _______ Copyright (C) 1999-2010 Johannes Gutenberg University
Mainz,
(__) * | Germany. This is free software with ABSOLUTELY NO
WARRANTY.
._) i N a C | You are welcome to redistribute it under certain
conditions.
<-------------' For details type `warranty;'.
Type ?? for a list of help topics.
> subs(5-exp(x),x==log(x));
5-log(x)
}}}
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/9891>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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