Numerical instability of pFq((1, 1, 1), (2, 2), x) in HypergeometricFunctions 0.3.17
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Assessment
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Newbie friendliness
- 45/100
Research direction
Run the Julia reproducer from the issue with HypergeometricFunctions 0.3.17 and inspect the plotted values of x*pFq((1, 1, 1), (2, 2), x) against the dilogarithm. Trace the numerical evaluation path for this parameter set and verify that the corrected result has no spurious poles and that its real part is continuous for arguments greater than 1.
Written by the indexing model from the issue text.
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:
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).
- Dominant language
- Julia
- Stars
- 76
- Forks
- 12
- PR merge metrics
- No merged PRs in 30d
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