#6882: bugs in conversion of variable names from Maxima to Sage
-------------------------------------+-------------------------------------
Reporter: was | Owner: rws
Type: defect | Status: needs_review
Priority: major | Milestone: sage-6.3
Component: calculus | Resolution:
Keywords: | Merged in:
Authors: Ralf Stephan | Reviewers: Karl-Dieter Crisman
Report Upstream: N/A | Work issues:
Branch: | Commit:
u/rws/bugs_in_conversion_of_variable_names_from_maxima_to_sage|
518de3e62533cd209997107f903192f1a31d118c
Dependencies: | Stopgaps:
-------------------------------------+-------------------------------------
Changes (by kcrisman):
* reviewer: => Karl-Dieter Crisman
Comment:
Well, it's an improvement, though still not perfect:
{{{
# Before
sage: sefms('%inf')
Inf
sage: sefms('%minf')
-Infinity
# After
sage: sefms('%inf')
+Infinity
sage: sefms('%minf')
-Infinity
}}}
Neither of these are infinity in Maxima, of course. And indeed here is
what the [http://maxima.sourceforge.net/docs/manual/en/maxima_6.html#SEC32
Maxima manual] says about identifiers:
{{{
(%i1) %an_ordinary_identifier42;
(%o1) %an_ordinary_identifier42
}}}
"A numeral may be the first character of an identifier if it is preceded
by a backslash. " But I don't know that we need to translate all
identifiers in Maxima to Sage here... I guess I'm torn about that.
{{{
sage: timeit('sefms(str(ex))')
5 loops, best of 3: 2.19/2.14/2.15 s per loop (without #6882)
5 loops, best of 3: 2.13/2.11/2.12 s per loop (with #6882)
}}}
Of course, thinking about it, that string is a Sage string, not a Maxima
string, so `%time R = random_expr(50,nvars=2); sefms(repr(R._maxima_()))`
is probably more accurate, but that is also wildly variant on the
expression.
Okay, as far as I can tell this will not break anything (let's really
hope!) and fixes the actual problem without slowing down what is already a
very slow process (even for `random_expr(5,nvars=2)` it's 2-3 milliseconds
either way). Step in right direction, and again most people should not be
affected in the slightest. If passes tests, let's get it in.
--
Ticket URL: <http://trac.sagemath.org/ticket/6882#comment:38>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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