The definition given by Alan is the derivative of a boolean function wrt a boolean variable. In Chris's expression, the variable is real, not boolean.
Aaron Meurer On Wed, Sep 20, 2017 at 1:50 PM, Alan Bromborsky <[email protected]> wrote: > I afraid I can't help there. I am good at finding things with google. This > might help, maybe? > > http://pyeda.readthedocs.io/en/latest/reference/boolalg/boolfunc.html > > > On 09/20/2017 12:57 PM, Chris Smith wrote: > > I will need some help interpreting that. Here's my attempt: > >>>> f = eq = ITE(x<1,x,Eq(y,1)).to_nnf(); eq > (x∨x≥1)∧(y=1∨x<1)(x∨x≥1)∧(y=1∨x<1) >>>> eq.subs(x, 0) > False >>>> eq.subs(x, 1) > y = 1 > > > I'm not sure how I am supposed to add these mod 2. Maybe `(0 + ITE(Eq(y,1), > 1, 0)) % 2`? So does x change the value of f? The answer depends on y, > doesn't it? If y is 0 then the value of x doesn't change f but it it is 1 > then it does. So is the derivative wrt x `Eq(y, 1)`? > > On Tuesday, September 19, 2017 at 4:06:04 PM UTC-5, brombo wrote: >> >> On 09/19/2017 04:24 PM, Aaron Meurer wrote: >> > I'm not sure the derivative really makes sense. I would either error >> > or leave it unevaluated. >> > >> > Aaron Meurer >> > >> > On Tue, Sep 19, 2017 at 9:19 AM, Chris Smith <[email protected]> wrote: >> >> In PR #13204 I encountered the question of what to do with the >> >> derivative if >> >> a Boolean. A Boolean is true or false but may contain expressions >> >> within >> >> relationals, For example, `x**2 < y` depends on x and y but the Boolean >> >> value is a "square wave" for this relational. Does a derivative wrt x >> >> or y >> >> even make sense? Should an error, 0 or something else be done for a >> >> return >> >> value? >> >> >> >> /c >> >> >> >> -- >> >> 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 https://groups.google.com/group/sympy. >> >> To view this discussion on the web visit >> >> >> >> https://groups.google.com/d/msgid/sympy/13fc1fdc-caba-4336-a7df-148efa2f716a%40googlegroups.com. >> >> For more options, visit https://groups.google.com/d/optout. >> >> >> See link - >> >> https://www.encyclopediaofmath.org/index.php/Boolean_differential_calculus >> > -- > 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 https://groups.google.com/group/sympy. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/2364638a-ed60-4a6d-aa09-af6b9f738a01%40googlegroups.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 https://groups.google.com/group/sympy. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/bb2fbf12-55d8-fcbe-23f6-1406d7cac078%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 https://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6%2B43CU%2BSfqivz9Gys9sdH%3D2WqozLZgMYgxuEPKqk5aVcA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
