On Thu, Feb 4, 2016 at 12:07 PM, Shekhar Prasad Rajak < [email protected]> wrote:
> Thanks for sharing the links, Aaron. > Regarding Issue https://github.com/sympy/sympy/issues/10426 ,I opened a > PR : https://github.com/sympy/sympy/pull/10482 > this PR is able to give solutions in simple form in many cases. > When I was trying to solve this issue, I found that solveset converts all > the trigonometric equations into exponential form then > solve them using solveset_complex . > I haven't find any method that solves trig equations using fu module. fu > module also need more simplify expression in different terms. > It is using this algorithms > > http://rfdz.ph-noe.ac.at/fileadmin/Mathematik_Uploads/ACDCA/DESTIME2006/DES_contribs/Fu/simplification.pdf > <http://rfdz.ph-noe.ac.at/fileadmin/Mathematik_Uploads/ACDCA/DESTIME2006/DES_contribs/Fu/simplification.pdf> > that contains simple formulas only. > > Right now solveset directly convert any trig expression to it's > corresponding exponential form. > But if we add fu module in this line : > > https://github.com/sympy/sympy/pull/10482/files#diff-eec0422923e8f100745c015cd8fdd6cfR540 > <https://github.com/sympy/sympy/pull/10482/files#diff-eec0422923e8f100745c015cd8fdd6cfR540> > then we get simplified trig equations.Then solve them using > solveset_complex , This may increase number of solutions.Isn't it ? > Other way can be implement a different algorithms. > I don't see how it would add solutions, other than maybe canceling out singularities (like cos(x)*sec(x)). I think it's also worthwhile to look into other algorithms. By the way, I still think the solving module should be organized around the abstractions of rewriting and decomposition (see https://groups.google.com/forum/#!msg/sympy/42GdMJ9ssyM/swC6bHVunP8J). That was written before solveset so I can't say for sure to what degree solveset already follows this pattern. Aaron Meurer > -- > Shekhar Prasad Rajak > > On Thursday, 4 February 2016 00:51:39 UTC+5:30, Aaron Meurer wrote: >> >> Another good resource for what's there and what doesn't work yet is >> https://github.com/sympy/sympy/blob/master/doc/src/modules/solvers/solveset.rst >> . >> >> Personally, I'd like to see solutions from equations involving >> trigonometric expressions improved. Right now you will often get an answer >> but it is not as simple as it could be (maybe this is more an issue of >> simplifying set expressions). For example, solveset(sin(x), domain=S.Reals) >> gives {2⋅n⋅π | n ∊ ℤ} ∪ {2⋅n⋅π + π | n ∊ ℤ} but it would be better if it >> gave {n⋅π | n ∊ ℤ}. I suggested a potential way to fix this at >> https://github.com/sympy/sympy/pull/9500#discussion_r39220151. Fixing >> this by improving simplifying set expressions would be nice because then it >> would work even for set expressions that don't come directly from solveset. >> >> A related use-case I found where solveset fails is solving f(x) = f(x + >> a) for a not dependent on x. The ability to solve this in the positive or >> the negative would tell you if f(x) is periodic (and its period if it is). >> This currently fails even for sin(x) ( >> https://github.com/sympy/sympy/issues/10426). >> >> Aaron Meurer >> >> On Wed, Feb 3, 2016 at 2:05 PM, Shekhar Prasad Rajak < >> [email protected]> wrote: >> >>> >>> Hello, >>> my name is Shekhar Prasad Rajak.I want to discuss about Solver and >>> Solveset module >>> https://github.com/sympy/sympy/wiki/GSoC-2016-Ideas#solvers .I am going >>> to apply for GSoc'16, so trying to know >>> what sympy community expecting. >>> Solveset came to Replace all internal solve() calls >>> https://github.com/sympy/sympy/issues/8711 >>> So I should focus on Solveset,right? >>> I have some questions : >>> 1.What are the main problems/issues in Solver and Solveset right now? >>> 2.Is Solveset module done?If not,what are the main features, that should >>> be added ? >>> I have seen Harsh's PR : https://github.com/sympy/sympy/pull/7523 >>> It seems, these need some works : >>> -functions solvable by LambertW >>> -functions that can be recast as polynomials with a change of >>> variables this, for example; this can be >>> factored out of solve where multiple generators are handled >>> -use something like this : >>> https://github.com/sympy/sympy/pull/7523#issuecomment-62198981 >>> to handle the XFAILed test test_real_imag_splitting1, this will be >>> handled in the set module. >>> >>> 3.This is list of Issues/ Discussions I found. >>> >>> https://github.com/sympy/sympy/wiki/GSoC-2014-Application-Harsh-Gupta:-Solvers#relevant-issues-discussions-and-references >>> <https://github.com/sympy/sympy/wiki/GSoC-2014-Application-Harsh-Gupta:-Solvers#relevant-issues-discussions-and-references> >>> but I don't know, whether they are solved or not. >>> Issues which are still open in github repo, need solutions. >>> There are also links of pdf and research papers, I am not sure whether >>> they are implemented or not. >>> >>> 4.Can we use python library multiprocessing,Synchronization for the >>> faster execution?one issue was opened for the same,which is closed now.But >>> it is always better to take less time. >>> >>> >>> -- >>> Shekhar Prasad Rajak >>> >>> -- >>> 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/33a1b294-4a48-413a-a96f-90899291c1b0%40googlegroups.com >>> <https://groups.google.com/d/msgid/sympy/33a1b294-4a48-413a-a96f-90899291c1b0%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> 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/35c19f8c-0bc5-4aba-9b13-35bc16aff761%40googlegroups.com > <https://groups.google.com/d/msgid/sympy/35c19f8c-0bc5-4aba-9b13-35bc16aff761%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "sympy" group. 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