Axiom Computer Algebra System - Bugs: bug #10350, integrating UTS
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bug #10350: integrating UTS
Submitter: | Martin Rubey <kratt6> | ||
Submitted: | Sat 11 Sep 2004 12:34:23 PM UTC | ||
Category: | algebra | Severity: | 3 - Normal |
Item Group: | code bug | Status: | transferred |
Privacy: | Public | Assigned to: | None |
Originator Name: | Martin Rubey | Open/Closed: | Open |
Release: | Reproducibility: | None | |
Fixed Release: | |||
Error message: |
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Example of code trigerring the bug: | integrate((1/x)::UTS(FRAC POLY INT, x, 0),x)
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Internal cause: | The first bug is an indication that 1/x should not be of type UTS(x, FRAC POLY INT), UP(x, FRAC POLY INT) and so on. The second is an indication that QFCAT should have a function variables: % -> List Symbol. |
Sat 02 Oct 2004 12:09:22 PM UTC, comment #2: |
Anonymous |
Sat 02 Oct 2004 08:33:01 AM UTC, comment #1: Neither of these is a bug. In the first one, Axiom coerced 1/x into FRAC POLY INT correctly: the only / operation available in UTS is one induced from the coefficient domain, which requires the denominator to be in the coefficient domain, and the division is done termwise to the coefficients of the series. So 1/x ends up in FRAC POLY INT. Note that to obtain a Taylor series at x = 0 is mathematically is wrong, since 1/x is not defined at x=0. Also the way to obtain a Taylor series is taylor(func, x=a). If you do integrate(taylor(1/x,x=1),x), that would cause no problems. Note that the domain of this command is UTS(EXPR INT, x,1), so such towers are valid and necessary in Axiom. Note also there are only two exported[coerce] in UTS and they do NOT apply to 1/x. The x in UTS is like the x in UP and is different from the x in FRAC POLY INT. The representation is Stream Coef (no variable specified because it is univariate).
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Anonymous |
Sat 11 Sep 2004 12:34:23 PM UTC, original submission:
integrate((1/x)::UTS(FRAC POLY INT, x, 0),x) |
Martin Rubey <kratt6> |
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Follow 2 latest changes.
Date | Changed by | Updated Field | Previous Value | => | Replaced by |
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2006-02-18 | billpage1 | Status | None | ![]() |
transferred |
Example of code trigerring the bug | integrate((1/x)::UTS(FRAC POLY INT, x, 0),x) integrate((1/y)::UTS(FRAC POLY INT, x, 0),z) | ![]() |
integrate((1/x)::UTS(FRAC POLY INT, x, 0),x) integrate((1/y)::UTS(FRAC POLY INT, x, 0),z) |
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Corresponding source code
I disagree with the previous comment; x should be captured and not allowed in the FRAC POLY INT. (I agree that the second example in the original report is not a bug.)
But surely we can all agree that
integrate((1/x)::ULS(FRAC POLY INT, x, 0),x)
is a bug? The problem is the same: the 1/x is being treated in the coefficient domain. Note that
integrate(1/(x::ULS(FRAC POLY INT, x, 0)),x)
produces a correct result.
Dylan (dpt@math.harvard.edu)