#11201: Point users of solve() to the to_poly_solve option
----------------------------------------------------------+-----------------
Reporter: benjaminfjones | Owner: was
Type: enhancement | Status:
needs_work
Priority: minor | Milestone:
Component: interfaces | Resolution:
Keywords: solve, maxima, to_poly_solve, beginner | Work issues:
Report Upstream: N/A | Reviewers:
Karl-Dieter Crisman, Benjamin Jones
Authors: Andrew Fleckenstein | Merged in:
Dependencies: | Stopgaps:
----------------------------------------------------------+-----------------
Changes (by benjaminfjones):
* reviewer: Karl-Dieter Crisman => Karl-Dieter Crisman, Benjamin Jones
Comment:
That's a good start. Thanks for the contribution!
I started looking at the patch and I have a couple of comments. First, I
tried running doctests on `sage/symbolic/expression.pyx` and there are a
lot of new failures due to the unexpected info message that's been added.
For example,
{{{
jonesbe@macbook ~/sage/latest/devel/sage> ../../sage -t
sage/symbolic/expression.pyx
sage -t "devel/sage-test/sage/symbolic/expression.pyx"
**********************************************************************
File "/Users/jonesbe/sage/sage-5.0.beta12/devel/sage-
test/sage/symbolic/expression.pyx", line 7761:
sage: f.roots(x)
Expected:
[(a, 1), (-I, 1), (I, 1), (1, 3), (-1, 3)]
Got:
For explicit results, try setting the 'to_poly_solve' keyword to True.
[(a, 1), (-I, 1), (I, 1), (1, 3), (-1, 3)]
}}}
There might be other doctest failures besides ones related to the new
message, I don't have time to look through them all right now.
-----
I'm still not sure what exactly setting `to_poly_solve='use_grobner=true'`
does. Consider the following Sage-5.0.beta12 session (with your patch
applied):
Here is what Maxima (5.26.0) does:
{{{
sage: maxima('load(to_poly_solver)')
"/Users/jonesbe/sage/sage-5.0.beta12/local/share/maxima/5.26.0/share/contrib/to_poly_solver.mac"
sage: maxima('to_poly_solve([x^2+y^2=2^2,(x-1)^2+(y-1)^2=2^2],[x,y]);')
%union()
sage:
maxima('to_poly_solve([x^2+y^2=2^2,(x-1)^2+(y-1)^2=2^2],[x,y],use_grobner=true);')
%union([x=-(sqrt(7)-1)/2,y=(sqrt(7)+1)/2],[x=(sqrt(7)+1)/2,y=-(sqrt(7)-1)/2])
}}}
Here is what Sage does (same system of equations, same options):
{{{
sage: solve(x == sqrt(x+1), x)
For explicit results, try setting the 'to_poly_solve' keyword to True.
[x == sqrt(x + 1)]
sage: solve(x == sqrt(x+1), x, to_poly_solve=True)
For explicit results, try setting the 'to_poly_solve' keyword to True.
[x == 1/2*sqrt(5) + 1/2]
sage: solve(x == sqrt(x+1), x, to_poly_solve='use_grobner=true')
For explicit results, try setting the 'to_poly_solve' keyword to True.
[x == 1/2*sqrt(5) + 1/2]
}}}
So it seems like `use_grobner` has no effect, despite it having an effect
in Maxima. Is it always set to true when `to_poly_solve=True` is
specified? If so, we should really get rid of this confusing solve option.
If there is a good example where it actually has an effect, that should be
added to the EXAMPLES:: section in the solve docs. The example
illustrating it right now doesn't change if you set `to_poly_solve=True`
instead of `to_poly_solve='use_grobner=true'`:
{{{
sage: solve(x == sqrt(x+1), x)
For explicit results, try setting the 'to_poly_solve' keyword to True.
[x == sqrt(x + 1)]
sage: solve(x == sqrt(x+1), x, to_poly_solve=True)
For explicit results, try setting the 'to_poly_solve' keyword to True.
[x == 1/2*sqrt(5) + 1/2]
sage: solve(x == sqrt(x+1), x, to_poly_solve='use_grobner=true')
For explicit results, try setting the 'to_poly_solve' keyword to True.
[x == 1/2*sqrt(5) + 1/2]
}}}
Last comment: I think the info message should not be printed when I do
give `to_poly_solve=` a value (see last two commands in the last session).
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11201#comment:6>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/sage-trac?hl=en.
