darkhistory.utilities.spence_series_diff¶
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darkhistory.utilities.
spence_series_diff
(b, a)¶ Returns the Taylor series for Li2(b) - Li2(a).
Li2 is the polylogarithm function defined by
\[\text{Li}_2(z) \equiv \sum_{k=1}^\infty \frac{z^k}{k^2} \,.\]Parameters: - a : ndarray
Input for Li2(a).
- b : ndarray
Input for Li2(b).
Returns: - ndarray
The Taylor series Li2(b) - Li2(a), up to the 11th order term.