I changed priority to "critical". This feature is obviously highly demanded among the community (cf. https://trac.sagemath.org/ticket/25034#comment:6).
Best, Michael Jonathan Thornburg schrieb am Donnerstag, 8. April 2021 um 20:12:19 UTC+2: > There have been longstanding issues with spherical harmonics in SageMath, > notably as described in > https://groups.google.com/g/sage-support/c/I_d_meMxRbM/m/Esxo5UO2BAAJ > In that the latter thread, Eric Gourgoulhon's message of 2019-06-15 gives > a simple test case: > from sage.functions.special import SphericalHarmonic > theta,phi = var('theta phi') > spherical_harmonic(1,1, theta,phi) > producing the (wrong) result > -1/4*sqrt(3)*sqrt(2)*sqrt(-sin(theta)^2)*e^(I*phi)/sqrt(pi) > whereas the correct result would be > -1/4*sqrt(6)*e^(I*phi)*sin(theta)/sqrt(pi) > > Eric also noted that this problem was apparently a consequence of > https://trac.sagemath.org/ticket/25034 > and suggested a workaround, using the spin-weighted spherical harmonics > from the SageMath /kerrgeodesics_gw/ package. > > > An update: > * As of 9.3.rc2, SageMath's builting spherical harmonics are still broken > (same result as above for Eric's test case). > * As of 9.3.rc2, the /kerrgeodesics_gw/ package fails to load (it worked > fine for me in 9.2.). I'll report that error to the bhptoolkit.org > issue tracker. > > And a question: > Given that the underlying problem > https://trac.sagemath.org/ticket/25034 > is unlikely to be fixed for 9.3, should we perhaps put a note in the > documentation for 9.3 that spherical harmonics are unreliable at present? > > -- > -- "Jonathan Thornburg [remove -animal to reply]" <[email protected]> > Dept of Astronomy & IUCSS, Indiana University, Bloomington, Indiana, USA > currently on the west coast of Canada > "There was of course no way of knowing whether you were being watched > at any given moment. How often, or on what system, the Thought Police > plugged in on any individual wire was guesswork. It was even conceivable > that they watched everybody all the time." -- George Orwell, "1984" > -- 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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-devel/908ce50b-0e23-4d87-90d4-65a435bde3fen%40googlegroups.com.
