Updates:
Cc: ondrej.certik
Labels: -module-series Series
Comment #2 on issue 431 by asmeurer: series bug: w**(-1-w) *
sin(2*w)**(1+w)
http://code.google.com/p/sympy/issues/detail?id=431
This doesn't traceback anymore:
In [2]: (x**(-1-x) * sin(2*x)**(1+x)).series(x, 2)
Out[2]: O(log(x)**12)
Is this the correct result?
By the way, I bisected, and it seems it was fixed when I refactored
expand():
2fea550d5618e6350d537a7d9b06f224751b1fdf is the first bad commit
commit 2fea550d5618e6350d537a7d9b06f224751b1fdf
Author: Aaron Meurer <[email protected]>
Date: Tue Jun 16 23:01:02 2009 -0600
Refactored expand, fixing issues 1455, 1453, and 1445
Expand hints are now much more specific. power_exp, power_base,
multinomial,
mul, and log have replaced basic as the default hints. basic remains
as a
default hint so it can be used for things that don't fit into those
other hints
but needs to be automatic.
All expand functions include a deep keyword argument which determines
if it
passes on the expand hints to the inner parts of an expression.
I added expand_mul, expand_log, expand_func, expand_trig, and
expand_complex
functions to make it easier to only expand with those hints.
This also changes a few other things internally. expand_hint functions
no
longer return None if they do not expand; they return the expression.
Mul and
Add now have basic expand_hint functions that expands through the terms
of the
expression. This replaces similar code in Basic because not all Basic
subclasses works with class.new(*class.args) (e.g., Poly).
This fixes all the tests that it made fail, either by changing the test
to an
equivalent expression or by changing the expand calling routine in some
code
somewhere.
The integration engine relies on expand(log(x**2)) => 2*log(x) working
always,
even though it is technically only true when x is positive. This keeps
the old
behavior. Hopefully, it will be easier to fix when we have the new
assumptions
system.
Also cleaned up code in powsimp.
Signed-off-by: Ondrej Certik <[email protected]>
:040000 040000 cb2c6c1793a8e2ee1981bf52051fe7c97c505ae1
8a056931917f337696ab5e7241448b46f39503d2 M sympy
By the way, I am guessing this is still not right, because I also get, for
example:
In [3]: (x**(-1-x) * sin(2*x)**(1+x)).series(x, 100)
Out[3]: O(log(x)**12)
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