Thanks for reporting the bug. I opened trac ticket #33962 <https://trac.sagemath.org/ticket/33962> to fix it.
On Monday, June 6, 2022 at 4:21:01 PM UTC-6 vdelecroix wrote: > There is indeed a problem > > sage: legendre_P(2, 0) > 1/2 > sage: legendre_P(2.0, 0.0) > -0.500000000000000 > > On Mon, 6 Jun 2022 at 20:38, Dan Cross <daniel...@gmail.com> wrote: > > > > Hi, > > It seems the special values of the Legendre Polynomials evaluated at > zero are hard coded to be positive, but the sign should alternate. So, > while legendre_P(0,0) correctly gives 1 and legendre_P(4,0) correctly gives > 3/8, legendre_P(2,0) gives +1/2 instead of -1/2. Evaluating legendre_P(2,x) > for any x close to zero gives a value close to -1/2 as it should. This > problem is even evident on the documentation page ( > https://paulmasson.github.io/sagemath-docs/functions/legendre_P.html) > which shows the graph of P_2 passing through -1/2 but tabulates the special > value at zero as +1/2. > > > > Thanks. > > > > -- > > You received this message because you are subscribed to the Google > Groups "sage-devel" group. > > To unsubscribe from this group and stop receiving emails from it, send > an email to sage-devel+...@googlegroups.com. > > To view this discussion on the web visit > https://groups.google.com/d/msgid/sage-devel/9745505a-d332-4b63-9acd-770123e0291dn%40googlegroups.com > . > -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-devel/f8829538-14ba-45d5-9675-f2fb1c4cc3acn%40googlegroups.com.
