See also https://github.com/sympy/sympy/pull/2580 which started some work
related to solving systems of equations.
On Monday, March 16, 2015 at 8:50:48 PM UTC-5, AMiT Kumar wrote:
>
> The primary hints doesn't have much significance, the sub hints
> are the main hints which would contain various methods, used
> to solve different equations.
>
> The primary hint is just the primary information we would like to extract
> from input, (I should rather rename it)
> to classify equation on the basis of univariate",
> "multivariate_or_parametric", "single_eq", "multiple_eq.
>
> For example:
>
> def classify_primaryhint(f):
> """Clasifies expression(s) `f` based on the primaryhints.
> Primaryhints are
> "univariate", "multivariate_or_parametric", "single_eq", "
> multiple_eq".
>
>
> Examples
> ========
>
>
> >>> from sympy import *
> >>> from sympy.solvers.solveset import *
> >>> from sympy.abc import x
> >>> classify_primaryhint(x**2 + 2*x + 1)
> >>> ['single_eq', 'univariate']
>
>
> """
>
>
> phints = []
>
>
> # classify by number of Equations, i.e single_eq or multiple_eq
> if not iterable(f):
> phints.append('single_eq')
> f = sympify(f)
> free_symbols = set(f.free_symbols)
>
>
> else:
> free_symbols = []
> for fi in f:
> fi = sympify(fi)
> free_symbols.append(fi.free_symbols)
> if len(f) > 1:
> phints.append('multiple_eq')
>
>
> # classify by univariate and multivariate
> if len(free_symbols) == 1:
> phints.append('univariate')
> elif len(free_symbols) > 1:
> phints.append('multivariate')
> return phints
>
>
>
> Thanks,
>
> AMiT Kumar
>
> On Tuesday, March 17, 2015 at 1:44:38 AM UTC+5:30, Aaron Meurer wrote:
>>
>> Sorry if you already answered this in the application and I didn't see
>> it, but what is the difference between primary hints and subhints?
>>
>> Also, I should point out that you're going to have to remove most (or
>> maybe all) of your formatting when you submit your proposal in
>> Melange. I would just try to make it look as good as possible in
>> Melange, and provide a link to the wiki so people can read it there.
>>
>> Aaron Meurer
>>
>> On Mon, Mar 16, 2015 at 1:39 PM, AMiT Kumar <[email protected]> wrote:
>> > Hi,
>> >
>> > Sorry for late reply, (I was busy with Mid terms & Assignments).
>> >
>> > Based on the above Ideas, I have made the draft of my Proposal on SymPy
>> > wiki, Please have a look:
>> >
>> https://github.com/sympy/sympy/wiki/GSoC-2015-Application-AMiT-Kumar--Solvers-:-Extending-Solveset
>>
>> >
>> >
>> > Thanks,
>> >
>> >
>> > AMiT Kumar
>> > 3rd Year Undergrad
>> > Delhi Technological University
>> > www.iamit.in
>> >
>> > On Tuesday, March 10, 2015 at 12:15:15 AM UTC+5:30, Aaron Meurer wrote:
>> >>
>> >> That sounds good, except as I noted at
>> >> https://groups.google.com/forum/#!msg/sympy/42GdMJ9ssyM/swC6bHVunP8J,
>> >> it's very important to build this around a framework of rewriting and
>> >> decomposition. You want to be able solve, f(g(x)) = 0, where f is a
>> >> polynomial and g is a lambertW (for example). You want the hints to
>> >> be as simple as possible, and any complicated equations to be solvable
>> >> by an application of possibly many hints. This is more complicated
>> >> than what the ODE solver does.
>> >>
>> >> Rewriting basically boils down to simplifying the matching portion of
>> >> the hints. This is something that is not done very well in the ODE
>> >> system, so I would only look there to see how it is lacking.
>> >>
>> >> You want each hint to match a simple pattern, and then have some set
>> >> of rules on how to rewrite different expressions to that pattern
>> >> mathematically, even if they don't match it structurally. I would take
>> >> a look at the rules system used in the fu algorithm, and in the unify
>> >> submodule. Also take a look at Francesco's pattern matching
>> >> suggestions (search the mailing list and the wiki).
>> >>
>> >> Aaron Meurer
>> >>
>> >> On Sun, Mar 8, 2015 at 12:18 AM, AMiT Kumar <[email protected]>
>> wrote:
>> >> > Hi,
>> >> > I was thinking, How about designing the solveset similiar
>> >> > to the ODE Module . Something like hints system to classify solvers?
>> >> >
>> >> > Example:
>> >> >
>> >> > primaryhint = [
>> >> > "univariate",
>> >> > "multivariate",
>> >> > "single_eq",
>> >> > "multiple_eq"
>> >> > ]
>> >> >
>> >> >
>> >> > subhints = [
>> >> > 'solve_linear_system'
>> >> > 'linear_trig',
>> >> > 'polynomial',
>> >> > 'transcendental',
>> >> > 'piecewise',
>> >> > 'relational'
>> >> > 'solve_lambertw'
>> >> > 'miscellaneous'
>> >> > ]
>> >> >
>> >> >
>> >> > def classify_solver(f, symbols=None):
>> >> > """
>> >> > Clasifies the input equation(s)/function(s) to solve for, into
>> >> > possible
>> >> > hints such as linear, univariate, multivariate, etc.
>> >> > """
>> >> > hints = []
>> >> >
>> >> > # Methods to classify Equations
>> >> >
>> >> > def solveset(f, symbol=None):
>> >> >
>> >> > if eq_type == 'linear':
>> >> > solve_linear(f, symbol)
>> >> >
>> >> > if eq_type == 'linear_system':
>> >> > solve_linear_system(f, symbol)
>> >> >
>> >> > .
>> >> > .
>> >> > . and so on
>> >> >
>> >> >
>> >> >
>> >> > In that case we will be able to add new solvers, without messing
>> with
>> >> > the others, and we will have a more robust and flexible framework
>> >> > which will be easy to extend.
>> >> >
>> >> > I think, building a robust framework, which felicitates further
>> >> > development, worth much more than adding new solvers.
>> >> >
>> >> > Thoughts from the community are invited.
>> >> >
>> >> > AMiT Kumar
>> >> >
>> >> > --
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>> >> > To post to this group, send email to [email protected].
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>> >> > To view this discussion on the web visit
>> >> >
>> >> >
>> https://groups.google.com/d/msgid/sympy/5b7393ef-7d4d-46f9-bfcd-dbbeb38639c4%40googlegroups.com.
>>
>>
>> >> >
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>> >
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>>
>>
>> >
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>>
>
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