#11606: simplify constraints in linear programs
----------------------------------+-----------------------------------------
Reporter: john_perry | Owner: ncohen
Type: enhancement | Status: needs_work
Priority: major | Milestone: sage-4.7.2
Component: linear programming | Keywords: sd32
Work_issues: | Upstream: N/A
Reviewer: | Author: john_perry
Merged: | Dependencies:
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Changes (by ncohen):
* status: needs_review => needs_work
Comment:
Hello John ! `:-)`
I really didn't think at first this method would need to use either min or
max later on :-)
Hopefully, this trick should work :
{{{
from __builtin__ import min as min_function
}}}
Could you also add in the explanation of the check_redundant parameter
what is a "redundant" constraint ? Something like "(two constraints are
redundant when one can be obtained from the other scalar by
multiplication)" or something of the kind ? `:-)`
Oh, and it looks like there are some missing "::" before the beginning of
Python code in the doctests, so those will not be properly formatted when
building the documentation.
{{{
sage -docbuild reference html
}}}
Two other remarks :
* Set is a Sage version of set, the latter being a purely Python thing.
The interest of Set is that it is hashable and immutable, while the "set"
can be modified. When you do not need the elements to be immutable, I'm
told the best is to use set. And this I was probably told after writing
this part `:-)`
* I thought that
{{{
min( x for x in range(3) if x != 0 )
}}}
would be faster than
{{{
min([ x for x in range(3) if x != 0 ])
}}}
as you do not create the list first, but it looks like the iterators
have a cost too :
{{{
sage: %timeit min( x for x in range(10000) if x != 0 )
125 loops, best of 3: 5.51 ms per loop
sage: %timeit min([ x for x in range(10000) if x != 0 ])
125 loops, best of 3: 4.56 ms per loop
sage: %timeit min(x for x in range(10) if x != 0)
625 loops, best of 3: 7.41 µs per loop
sage: %timeit min([ x for x in range(10) if x != 0 ])
625 loops, best of 3: 6.81 µs per loop
}}}
Nathann
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11606#comment:12>
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