Another sign/clearsign related bug?



>>>>> "Jaime" == Jaime Villate <villate at fe.up.pt> writes:

    Jaime> Hi,
    Jaime> could this bug be related to the sign/clearsign issue discussed
    Jaime> recently? (bug #2627,
    Jaime> http://www.math.utexas.edu/pipermail/maxima/2013/033768.html)

    Jaime> Maxima 5.30

    Jaime> (%i4) ode2 ('diff(y,x,2)-k^2*y,y,x);
    Jaime> Is k zero or nonzero?
    Jaime> nonzero;
    Jaime> (%o4) y = %k2 x + %k1

    Jaime> (Wrong; it was assumed that k=0)

    Jaime> It has already been fixed in 5.31 (I don't know how):

    Jaime> Maxima 5.31

    Jaime> (%i4) ode2 ('diff(y,x,2)-k^2*y,y,x);
    Jaime> Is k zero or nonzero?
    Jaime> nonzero;
    Jaime> (%o4) y = %k1*%e^(k*x)+%k2*%e^-(k*x)$

    Jaime> (Correct)

    Jaime> and I was wondering what changed that made ode2 work correctly again
    Jaime> and whether something similar could be done to solve #2627.

If it's not obvious from the commit logs, you can always use git
bisect to find the (set of) changes that made it work.

Ray