On Mon, Sep 16, 2013 at 5:56 AM, Moritz Beber <[email protected]> wrote: > Dear all, > > My question basically has two parts: > > 1.) I have a number of (a few thousand) logical expressions each consisting > of a handful of symbols (in total there are several thousand symbols as > well). Currently, I generate a dictionary (let's call it 'big_dict') with > the symbols and their truth values. Then I loop through each expression and > evaluate it by calling expr.subs(big_dict). This is painfully slow. I looked > through the source code for 'subs' a little and saw that it roughly > translates the dict into an iterable of old, new pairs which it then loops > through in order to apply replacements. Is there a more efficient way? I > guess what I could code but actually expect an evaluation of a boolean > expressions to do is: using the symbols in it, extract the values and solve.
You can try using xreplace, or (I belive) subs(simultaneous=True), which should only walk the expression tree once. > > 2.) Since I have many such expressions, am I missing a way to solve the > whole system? I'm not clear what you mean by "solve", but look at simplify_logic() and satisfiable(). Aaron Meurer > > Thank you for your insights, > Moritz > > -- > 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. > 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. For more options, visit https://groups.google.com/groups/opt_out.
