On Fri, Feb 20, 2015 at 9:57 AM, Petr Baudis <[email protected]> wrote: > On Thu, Feb 19, 2015 at 02:43:51PM -0700, Ondřej Čertík wrote: >> On Thu, Feb 19, 2015 at 5:35 AM, Petr Baudis <[email protected]> wrote: >> > On Wed, Feb 18, 2015 at 11:01:54AM -0600, Aaron Meurer wrote: >> >> On Tue, Feb 17, 2015 at 10:41 PM, Petr Baudis <[email protected]> wrote: >> >> > So one curious observation I have is that even if sym.solve() is given >> >> > multiple equations and only a single variable, it does yield a solution >> >> > in this case. I'm still confused about what the exact API contract of >> >> > sym.solve() is. Working "sometimes" leaves me unsure about what I can >> >> > or cannot rely on... >> >> >> >> Sadly, there is none. Part of this is due to algorithmic limitations >> >> (solve() is basically a bunch of heuristics, there are few guarantees >> >> that it will find a solution if it exists). But a lot of it is just >> >> poor design. We are trying to make the design better with the new >> >> solveset module. >> > >> > Thanks! Knowing this is quite valuable for me. >> > >> >> >> Right now I'm inclined to conclude that what I want to do *is* rather >> >> >> hard and I'd have to come up with some new algorithms to deal with >> >> >> this. >> >> >> (Or likely take a look at some other CASes first if any handle this >> >> >> case >> >> >> for me already.) >> >> >> >> If you find some other CAS that can do this better, please let us know >> >> and post here your solution. As Aaron said, we would like to improve >> >> our solver module. >> > >> > I will for sure - my plan is to take a hard look at Maple and a brief >> > look at Mathematica. If I won't be successful, I might come back to >> > SymPy and try to help improve the solveset module (I can't promise >> > I will have the time though, this was supposed to be just a small piece >> > of puzzle in a larger project - http://21robot.org/). >> >> Are you trying to do all of this: >> >> http://21robot.org/research_activities/math/ >> >> ? > > Actually, I'm working on physics questions (not sure why these aren't > listed on the homepage). The nature of the questions is not always > the same, but SAT questions are reasonable examples of what we are > trying to solve, e.g.: > > > http://papers.xtremepapers.com/SAT/SAT%20II%20Success%20Physics.pdf.pdf > > The pipeline should convert text to logical form (set of predicates > that describe the situation and the question) and currently the logical > form is transformed to Modelica statements and the situation is > simulated. I'm trying to explore an alternate avenue of converting the > predicates to a system of equations and solving them symbolically.
I see, thanks for the clarification. To me that sounds like a major project. Definitely keep us posted how it goes. Ondrej -- 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 http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CADDwiVCwweGihm1juUq-qDaAjgOcTO%3D3ocjR71TaxscVKb3BqQ%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
