But note that ``` sage: bool(Eq.substitute_function(B,tanh(t-C1).function(t))) True ```
Sign errors happen... Le lundi 4 avril 2022 à 01:14:29 UTC+2, [email protected] a écrit : > Nope. > > Using `sympy` through `sage` : > > ``` > sage: reset() > sage: t=var("t") > sage: B=function("B") > sage: Eq=-B(t)^2-B(t).diff(t)+1==0 > sage: import sympy > sage: Sol=sympy.dsolve(*map(sympy.sympify, (Eq, B(t))))._sage_() ; Sol > B(t) == -1/tanh(C1 - t) > sage: C1=var("C1") > sage: foo(t)=Sol.rhs() > sage: bool(Eq.substitute_function(B, foo)) > True > sage: bar(t)=tanh(C1-t) > sage: bool(Eq.substitute_function(B, bar)) > False > ``` > > HTH, > > Le lundi 4 avril 2022 à 00:39:41 UTC+2, [email protected] a écrit : > >> There is an issue in the sympy.dsolve module. When I was trying to solve >> the ode: -B(t)^2 - B'(t) +1 =0. The proper result should be tanh(C_1 - t), >> while the given result is the 1/tanh(C_1 - t). >> >> I can help to solve this issue as a GSOC project if provided the >> permission from the community. I often use the sympy package, and I love it >> as it is a competitive alternative to the Wolfram Mathematica. >> >> And I am now a master's student at the Mathematical Institute, Oxford >> University. Before coming here, I possess a computer science undergraduate >> degree. Here is my Linkdin >> <https://www.linkedin.com/in/kang-li-84949a154/>. >> >> [image: IMG_7136.jpg] >> > -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/sympy/43c45014-f83d-48df-ae08-605195938950n%40googlegroups.com.
