#11832: bug fixes for profile functions for the Steenrod algebra
--------------------------+-------------------------------------------------
Reporter: jhpalmieri | Owner: AlexGhitza
Type: defect | Status: new
Priority: minor | Milestone: sage-4.7.2
Component: algebra | Keywords:
Work_issues: | Upstream: N/A
Reviewer: | Author: John Palmieri
Merged: | Dependencies:
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Profile functions for the Steenrod algebra, especially at odd primes, are
a little buggy:
{{{
sage: P3 = SteenrodAlgebra(p=3, profile=(lambda n: Infinity, lambda n: 1))
sage: P3._has_nontrivial_profile()
False
}}}
This should be `True`.
{{{
sage: P3._profile
((+Infinity, +Infinity, +Infinity, +Infinity, +Infinity, +Infinity,
+Infinity, +Infinity, +Infinity, +Infinity, +Infinity, +Infinity,
+Infinity, +Infinity, +Infinity, +Infinity, +Infinity, +Infinity,
+Infinity, +Infinity, +Infinity, +Infinity, +Infinity, +Infinity,
+Infinity, +Infinity, +Infinity, +Infinity, +Infinity, +Infinity,
+Infinity, +Infinity, +Infinity, +Infinity, +Infinity, +Infinity,
+Infinity, +Infinity, +Infinity, +Infinity, +Infinity, +Infinity,
+Infinity, +Infinity, +Infinity, +Infinity, +Infinity, +Infinity,
+Infinity, +Infinity, +Infinity, +Infinity, +Infinity, +Infinity,
+Infinity, +Infinity, +Infinity, +Infinity, +Infinity, +Infinity,
+Infinity, +Infinity, +Infinity, +Infinity, +Infinity, +Infinity,
+Infinity, +Infinity, +Infinity, +Infinity, +Infinity, +Infinity,
+Infinity, +Infinity, +Infinity, +Infinity, +Infinity, +Infinity,
+Infinity, +Infinity, +Infinity, +Infinity, +Infinity, +Infinity,
+Infinity, +Infinity, +Infinity, +Infinity, +Infinity, +Infinity,
+Infinity, +Infinity, +Infinity, +Infinity, +Infinity, +Infinity,
+Infinity, +Infinity, +Infinity), (1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1))
}}}
All of the "Infinity"s should be omitted.
{{{
sage: SteenrodAlgebra(p=3, profile=((3,2,1), lambda n: 1))
Traceback (most recent call last)
...
TypeError: unsupported operand type(s) for -: 'NoneType' and 'int'
}}}
This error shouldn't happen.
These bugs are in the function
`steenrod_algebra_misc.normalize_profile_function` and in the method
`_has_nontrivial_profile` in `steenrod_algebra.SteenrodAlgebra_generic`.
The attached patch fixes these, and it also speeds up
`steenrod_algebra_misc.is_valid_profile:
{{{
sage: sage: from sage.algebras.steenrod.steenrod_algebra_misc import
is_valid_profile, normalize_profile
sage: pro = normalize_profile(lambda n: n)
sage: timeit('is_valid_profile(pro[0], pro[1], p=2)') # before
5 loops, best of 3: 334 ms per loop
sage: timeit('is_valid_profile(pro[0], pro[1], p=2)') # after
125 loops, best of 3: 3.99 ms per loop
}}}
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11832>
Sage <http://www.sagemath.org>
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