Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

MST: ReggeWheelerRadial returns inaccurate results without warning when insufficient precision is supplied for \omega #6

Open
jgcaribe opened this issue Jul 2, 2020 · 3 comments

Comments

@jgcaribe
Copy link

jgcaribe commented Jul 2, 2020

The following was observed when using the ReggeWheeler paclet version 0.2.0 with Mathematica 12.1

By running:
ReggeWheelerRadial[0, 62, N[66/1000, 32], {Method -> "MST" , "BoundaryConditions" -> "Up"}][38/5],
One gets:
0.049504398364466443420579668 + 0.217205837414011646653422619 I .

But increasing the \omega precision to 64 and running the same command:
ReggeWheelerRadial[0, 62, N[66/1000, 64], {Method -> "MST" , "BoundaryConditions" -> "Up"}][38/5]
We get:
-2.3569478178789971313441929282871005305115037874570680281*10^125 - 2.3656010145588055265180298405292161434055554963899593261*10^125 I

The second result is very different from the first one and seems to be robust, because it agrees to what one gets by using the "NumericalIntegration" method:
ReggeWheelerRadial[0, 62, N[66/1000, 32], Method -> {"NumericalIntegration", "Domain" -> {2 + 1/20, 10}}, "BoundaryConditions" -> "Up"][38/5]
Results in:
-2.35694781787899467243053936565*10^125 - 2.36560101455880240670000175428*10^125 I

For some reason, the parameters s = 0, \ell = 62, \omega = 66/1000 and r = 38/5 manage to produce an inaccurate result without trowing any warning if insufficient precision is given for \omega.

@barrywardell
Copy link
Member

This appears to be an issue with computing the renormalized angular momentum. For example,

RenormalizedAngularMomentum[0, 62, 0, 0, N[66/1000, 32]]

produces different results than

RenormalizedAngularMomentum[0, 62, 0, 0, N[66/1000, 64]]

@znasipak
Copy link

znasipak commented Jul 26, 2022

I think the monodromy calculation within RenormalizedAngularMomentum can be improved. I have a C++ implementation that is able to compute nu via monodromy that has no problem solving this case at finite precision

@barrywardell
Copy link
Member

It would certainly be interesting to compare the implementations. It has been a long-standing frustration that certain cases suffer from significant loss of precision.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
None yet
Projects
None yet
Development

No branches or pull requests

3 participants