JuliaMath / JuliaMath/HypergeometricFunctions.jl

Numerical instability of pFq((1, 1, 1), (2, 2), x) in HypergeometricFunctions 0.3.17

Open
#65 1 comment 0 reactions 0 assignees View on GitHub
Dominant language
Julia
Stars
76
Forks
12
PR merge metrics
No merged PRs in 30d

Description

Dear HypergeometricFunctions developers,

I was comparing the function `x*pFq((1, 1, 1), (2, 2), x)` with the dilogarithm and noticed multiple numerical instabilities in version 0.3.17.

To reproduce:
~~~.jl
using HypergeometricFunctions, Plots

dilog(x) = real(x * pFq((1, 1, 1), (2, 2), x))

plot(range(-1e3, 1e4, length = 1000), dilog)
~~~
Please find the output plot below. The shown function has multiple (pseudo-)poles, which should not be there (the real part of the dilogarithm is continuous for arguments greater than 1).

![dilog](https://github.com/JuliaMath/HypergeometricFunctions.jl/assets/225817/d7912727-da70-4d74-85af-d788bf25026b)

Contributor guide

No contributing guide indexed for this repository

Assessment

This issue has not been assessed yet.

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.