I think there is a bug. If you take the two expressions, subtract them, and call simplify(), you get a result that isn't 0. equals() also says they are different.
simplify() returning False is also a bug. Can you open two issues for these things? Just put some minimal code to create the expressions in the issue (i.e., just print the expressions using str()). Aaron Meurer On Tue, Jul 14, 2015 at 12:51 PM, G.B. <[email protected]> wrote: > Hey Aaron— > > Maybe the best way to capture an example is an IPython notebook? > > Let me know if this doesn’t work properly… > > Cheers— > > -- > 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/456E1996-FF9C-4339-8C44-5D207523E66B%40gmail.com > . > For more options, visit https://groups.google.com/d/optout. > > > > On Jul 13, 2015, at 10:25 , Aaron Meurer <[email protected]> wrote: > > > > On Sun, Jul 12, 2015 at 7:46 PM, G B <[email protected]> wrote: > >> What would case Eq.simplify() to return False? There isn't a lot of > >> computation time before the result. > > > > Can you show an example of what is doing this? > > > >> > >> Also why would using together() before substituting an expression lead > to a > >> numerically different result? > > > > How different? It's possible you are changing the numerical stability > > of the expression. Or it's possible there is a bug in together. > > > > Aaron Meurer > > > >> > >> I have a series of equations that I've been substituting in to each > other > >> building up a final symbolic result. My first pass at this gave a > result > >> that looks reasonable (though I haven't proven it correct) when I > convert it > >> to a numpy function after using > >> Eq.subs(dictionary of values for symbols).simplify().n() > >> and plot it. > >> > >> When I took the last symbolic equation to be substituted and use > >> Eq.together() on it before substituting to get a simpler result, the > >> Eq.subs().simplify() returns False. When I manipulate it differently > to get > >> it to successfully lambdify, the resulting plot is different (and > appears > >> wrong). > >> > >> Thanks-- > >> > >> -- > >> 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/1c324cfc-6bb3-4951-8cd7-22394a8c4bcd%40googlegroups.com > . > >> For more options, visit https://groups.google.com/d/optout. > > > > -- > > You received this message because you are subscribed to a topic in the > Google Groups "sympy" group. > > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/sympy/niic3OG_vhs/unsubscribe. > > To unsubscribe from this group and all its topics, 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/CAKgW%3D6JwOrGG84jxWe%3D0%3DsaKRmg8s%2BFE7WpRN5mSO%3D2PP-QZLg%40mail.gmail.com > . > > 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 http://groups.google.com/group/sympy. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/456E1996-FF9C-4339-8C44-5D207523E66B%40gmail.com > . > 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 http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6%2Bg%3D9x-O9BobcD6R6Wxxb%2BBQ_OW2paF0zOxntQ8VMVqpQ%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
