#17394: TypeError in Expression.simplify_hypergeometric()
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Reporter: mjo | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-6.5
Component: symbolics | Resolution:
Keywords: | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: | Stopgaps:
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Comment (by nbruin):
It's simply this:
{{{
sage: A=SR(x+y+x*y)
sage: A.operator()(*A.operands())
TypeError: op_add expected 2 arguments, got 3
sage: A.operator()
sage: A.operator()
<built-in function add>
}}}
We should probably not use the built-in function add to mark addition
etc., but instead use a variadic version. Same would apply to mul. This
issue arises in a lot of places. See for instance `maxima_lib.add_vararg`.
It's probably a change that would need to be made in pynac somewhere.
Other point:
{{{
op(*map(lambda o: o.simplify_hypergeometric(algorithm), ops))
}}}
is both more compactly and more efficiently expressed in python by
{{{
op(*(o.simplify_hypergeometric(algorithm) for o in ops))
}}}
Compare:
{{{
sage: def l(*args):
....: return list(args)
....:
sage: %timeit l( *[a.bit_length() for a in xrange(100)] )
100000 loops, best of 3: 10.2 µs per loop
sage: %timeit l( *(a.bit_length() for a in xrange(100)) )
100000 loops, best of 3: 12.9 µs per loop
sage: %timeit l( *map(lambda a: a.bit_length(), xrange(100)) )
10000 loops, best of 3: 17.9 µs per loop
}}}
Basically: don't use "map" in python unless it's considerably more
convenient than the corresponding list comprehension.
--
Ticket URL: <http://trac.sagemath.org/ticket/17394#comment:1>
Sage <http://www.sagemath.org>
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