On Sun, 10 Apr 2022 at 16:40, 'كاي' via sympy <sympy@googlegroups.com> wrote: > > Hi Oscar, > > Thanks for the advice, I am looking to prompty begin condensing my proposal > and making contributions to the SymPy codebase. > > To eliminate some confusion, would you be able to explain how a solver for a > linear system of inequalities would be integrated into the CAD algorithm, as > from my understanding, we can input a linear system into the CAD and it would > output cells from which we can easily determine the solution set of the > system? > > Essentially this would be doing the same thing twice, or am I mistaken - > could this solver be a prerequiasite check to see if the system has a > solution before applying the CAD?
Essentially CAD is a method for solving systems of polynomial inequalities in multiple real variables. Simpler methods exist for solving systems of linear inequalities but those are not yet implemented in SymPy. Adding solvers for linear inequalities would be much easier and would have immediate applicability. Even if SymPy had CAD it would not make sense to use it for linear inequalities where more efficient methods exist. > Furthermore, can you reccommend which part of this project/idea would be > suitable for my first contribution to SymPy, this will also be my patch > requirement for GSoC, I was thinking maybe a data structure to hold the set > of polynomial inequlaities but it would be great to hear your thoughts first? I don't think it's worth adding a data structure for this. A list of inequalities can already be represented easily. Linear systems of inequalities are typically represented using matrices. Polynomial systems can be represented just as lists of polynomials. > Also can you kindly explain a little more about what you meant by assumptions > system in your previous reply? The point is that it would be good to be able to say something like "assume x + y > 0 and x - y < 1" and then use that to simplify other conditional expressions like Piecewise. Making this work means being able to conclude that e.g. the given set of inequalities implies that say "y > 0" or something. For that a solver for systems of inequalities is needed. -- Oscar -- 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 sympy+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAHVvXxSQjgfRh_Dx31wfxaB8c15qUk8NY_dANtwYhegRNc22ng%40mail.gmail.com.
