Dividing by zero is not the only place where you can have a real discontinuity. It can also occur from taking a fractional power of a negative number (like sqrt(x)), or a pole in a function (like log(x) at x=0). For the first, we need good inequality solving. For the second, we need to invent an API for functions to say where their poles are, and other information about them.
Aaron Meurer On Thu, May 2, 2013 at 10:00 PM, Chris Smith <[email protected]> wrote: > 2. Finding all points of continuity in the function (if any), and checking > if the function is continuous at a given point or a given interval. > > I think something you could use to do this is denoms: > > denoms(eq, symbols=None) > Return (recursively) set of all denominators that appear in eq > that contain any symbol in iterable ``symbols``; if ``symbols`` is > None (default) then all denominators with symbols will be returned. > > Examples > ======== > > >>> from sympy.solvers.solvers import denoms > >>> from sympy.abc import x, y, z > > >>> denoms(x/y) > set([y]) > > >>> denoms(x/(y*z)) > set([y, z]) > > >>> denoms(3/x + y/z) > set([x, z]) > > So the singularities are located where the denominators are zero -- so the > union of all solutions to the denominators being zero should be that set of > points. > > -- > 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?hl=en-US. > For more options, visit https://groups.google.com/groups/opt_out. > > -- 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?hl=en-US. For more options, visit https://groups.google.com/groups/opt_out.
