On Mon, Feb 29, 2016 at 2:05 AM, AMiT Kumar <[email protected]> wrote: > Hi Kshitij, > > Good to hear that you want to work on solvers. Here are my comments on your > queries. > > 1. Search Based Solvers: > > This idea is currently vague, we need to figure out how exactly > we can develop this. It would be ambitious to develop this idea and It > should be > accompanied with lot of research. Currently an abstract is written in the > docs: > https://github.com/sympy/sympy/blob/master/doc/src/modules/solvers/solveset.rst > > 2. Simplifying solutions returned from equations involving trigonometric > expressions: > > With the Introduction of solveset an important problem of representing > infinite solution > has been solved to some extent, but still there are some issues with > ImageSet Union, > due to which a lot of simpler results are not displayed properly. This needs > to be figured > out to get better ImageSet Union. > > In [10]: solveset(sin(x), x) > Out[10]: {2⋅n⋅π | n ∊ ℤ} ∪ {2⋅n⋅π + π | n ∊ ℤ} > > In [11]: solveset(sin(3*x), x) > Out[11]: > ⎧ 2⋅π ⎫ ⎧ 2⋅π > {2⋅n⋅π | n ∊ ℤ} ∪ {2⋅n⋅π + π | n ∊ ℤ} ∪ ⎨2⋅n⋅π - ─── | n ∊ ℤ⎬ ∪ ⎨2⋅n⋅π + ─── > | > ⎩ 3 ⎭ ⎩ 3 > > ⎫ ⎧ π ⎫ ⎧ π ⎫ > n ∊ ℤ⎬ ∪ ⎨2⋅n⋅π - ─ | n ∊ ℤ⎬ ∪ ⎨2⋅n⋅π + ─ | n ∊ ℤ⎬ > ⎭ ⎩ 3 ⎭ ⎩ 3 ⎭ > > > Here is a previous approach on fixing this: > https://github.com/sympy/sympy/pull/7673
Also https://github.com/sympy/sympy/pull/9500/files#r39220151. Aaron Meurer > > 3. Implementing more Equation solvers > > A lot of thing which needs to be done is already done in old solve, like the > solving of multivariate equation solver, you need to figure out how that > works > and how you can port those in solveset following the principles of solveset. > https://github.com/sympy/sympy/issues/10008 > >> I found this paper [5] which talks about implementing a parallel Gauss >> method for solving this issue. Is it relevant ? > > > This paper seems like implementing linear system solver, which is already > implemented as linsolve. > > 4. Solving f(x + a) - f(x) = 0 equations: [7] > > This needs to figured out. > > >> >> 5. Building the set infrastructure: >> Implementing functions to handle multidimensional ImageSet >> Can we be more elaborate on what other features are we expecting ? > > > > See this for motivation: https://github.com/sympy/sympy/issues/10008 > > > Best Regards, > Amit Kumar > > On Tuesday, February 23, 2016 at 7:56:31 PM UTC+5:30, Kshitij Saraogi wrote: >> >> Hello, >> >> >> I am Kshitij Saraogi and I will be a GSoC applicant this year under SymPy. >> >> >> I wanted to discuss about the Solvers project.[1] >> >> After going through the discussions mentioned on the Ideas page, I would >> like to get inputs on a few ideas for this project: >> >> >> 1. Search based Solvers [2]: >> >> I find this idea quite intriguing. I understand only an abstract >> view of the idea was presented there. >> >> I think we should try to implement this as it would make the API >> cleaner and robust. >> >> Since, not much has been written about this, I would like to know >> more about it. >> >> - What is the methodology we are thinking to use for ranking solutions >> (if any)? >> - What would be the parameters on which the cost function of different >> sets depend ? >> So, I would appreciate guidance in this direction. >> >> >> 2. Simplifying solutions returned from equations involving >> trigonometric expressions: >> >> The solveset module needs improvement with regards to the >> trignometric equation solver. >> >> An equation,as simple as, sin(x)=0 gives an output which should be >> simplified. >> >> This should be a big concern. >> >> What would be some good starting points to get an overview of the >> issue and possibly a few ideas to resolve this ? >> >> >> 3. Implementing more equation solvers: [3] >> >> System of multivariate linear equations. >> >> Nonlinear multivariate equation solver. >> >> Equations solvable by LamberW function (Transcendental equation solver) >> >> Nested trignometric expressions. >> >> As Amit pointed out here[4], that we need (ii) and (iii) to make solveset >> at par with solve. >> >> I found this paper [5] which talks about implementing a parallel >> Gauss method for solving this issue. Is it relevant ? >> >> While fixing an issue [6], I came to know that we need a more >> reliable multivariate nonlinear equation solver. >> >> I would like to know more about these solvers with respect to >> their immediate need and the possible methods of their implementation. >> >> >> >> 4. Solving f(x + a) - f(x) = 0 equations: [7] >> >> While going through some issues, I found that the current solvers >> can’t handle these type of equations. >> >> >> >> 5. Building the set infrastructure: >> >> Implementing functions to handle multidimensional ImageSet >> >> Can we be more elaborate on what other features are we expecting ? >> >> I would really appreciate if someone can point out the issues I may have >> missed. >> >> Also, any relevant resources or links for further readings would help too. >> >> >> Thanks, >> >> Kshitij Saraogi > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at https://groups.google.com/group/sympy. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/98d1cacd-0ff4-45ef-a0b7-d4b1b2a47c28%40googlegroups.com. > > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6K7Na9DLYFOfyibELiYGGcNdqAEeEY5fhE0847UV7yayA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
