#12834: Modify subs so that it can accept multiple equations just like subs_expr
---------------------------+------------------------------------------------
Reporter: JoalHeagney | Owner: AlexGhitza
Type: enhancement | Status: new
Priority: minor | Milestone: sage-5.0
Component: algebra | Keywords: subs algebra solving
Work issues: | Report Upstream: N/A
Reviewers: | Authors: Michael Orlitzky
Merged in: | Dependencies:
Stopgaps: |
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This came up as a method of passing solutions from solve back into
symbolic equations:
{{{
f(x,y) = (1-x)^2 + 100*(y - x^2)^2
solution = solve([f.diff(ar) for ar in f.args()],f.args())[0]
Gives me a list of solutions as:
[x=1;y=1]
Is there any way to programatically substitute this list of equalities
back into f?
}}}
The solution provided by Michael Orlitzky was
{{{
f(x,y).subs_expr(*solution)
}}}
Anycase, as noted by Michael, it would be nice if subs had the same
behaviour:
{{{
Passing it one equation does work,
sage: f.subs(x == 1)
y + z + 1
But more than one doesn't,
sage: f.subs(x == 1, y == 2)
...
TypeError: substitute() takes at most 1 positional argument (2 given)
I guess all that's missing is the ability to pass it multiple equations,
like `subs_expr`. It would probably be easy to add that ability to
`subs` if you want to create a ticket for something.
}}}
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/12834>
Sage <http://www.sagemath.org>
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