#16896: rework of row_reduced_form/weak_popov_form calling convention
-------------------------------------+-------------------------------------
Reporter: ketzu | Owner:
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-6.7
Component: linear algebra | Resolution:
Keywords: polynomial matrix | Merged in:
Authors: David Mödinger, | Reviewers:
Johan S. R. Nielsen | Work issues:
Report Upstream: N/A | Commit:
Branch: | 67c5636f25e30655a6cc5084f6e426fb181049ce
u/jsrn/rework_of_row_reduced_form_weak_popov_form_calling_convention|
Stopgaps:
Dependencies: #16888 |
-------------------------------------+-------------------------------------
Changes (by jsrn):
* status: needs_work => needs_review
Old description:
> The calling convention of `row_reduced_form` and `weak_popov_form` is
> bizarre and should be fixed.
>
> 1. It takes a parameter `ascend` but this is ignored. It's original
> purpose was something like sorting the rows, but this is not part of weak
> Popov form or row reduced, and shouldn't pollute this method.
>
> 2. It returns a 3-tuple `(W,U,d)`. Usually, `W` is the only object of
> interest (the row reduced form), while `U` is a transformation matrix
> which can sometimes be useful. `d` can be computed directly from `W` and
> shouldn't be returned at all.
>
> 3. When the input is a matrix over a polynomial ring, it returns the
> output as over the fraction field, though the output always *lie* in the
> polynomial ring.
>
> I've added optional parameters `transformation = False` for returning
> `U`. To enable printing a deprecation warning for at least a year while
> supporting the old call style, I've added optional parameter `old_call =
> True`. Set this to `False` to get the future call style and disable
> deprecation warning. In one year, we'll change the default behaviour but
> retain `old_call` as an acceptable argument, but print a deprecation
> warning if one sets it. In two years, we can finally remove `old_call`
> and have the clean calling convention. <sigh>...
New description:
The calling convention of `row_reduced_form` and `weak_popov_form` is
bizarre and should be fixed.
1. It takes a parameter `ascend` but this is ignored. It's original
purpose was something like sorting the rows, but this is not part of weak
Popov form or row reduced, and shouldn't pollute this method.
2. It returns a 3-tuple `(W,U,d)`. Usually, `W` is the only object of
interest (the row reduced form), while `U` is a transformation matrix
which can sometimes be useful. `d` can be computed directly from `W` and
shouldn't be returned at all.
3. When the input is a matrix over a polynomial ring, it returns the
output as over the fraction field, though the output always *lie* in the
polynomial ring. This is senseless and confusing.
I've added optional parameters `transformation = False` for returning `U`.
To enable printing a deprecation warning for at least a year while
supporting the old call style, I've added optional parameter `old_call =
True`. Set this to `False` to get the future call style and disable
deprecation warning. In one year, we'll change the default behaviour but
retain `old_call` as an acceptable argument, but print a deprecation
warning if one sets it. In two years, we can finally remove `old_call` and
have the clean calling convention. <sigh>...
--
Comment:
Done!
--
Ticket URL: <http://trac.sagemath.org/ticket/16896#comment:20>
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