scipy.special.i1¶
- scipy.special.i1(x) = <ufunc 'i1'>¶
Modified Bessel function of order 1.
Defined as,
\[I_1(x) = \frac{1}{2}x \sum_{k=0}^\infty \frac{(x^2/4)^k}{k! (k + 1)!} = -\imath J_1(\imath x),\]where \(J_1\) is the Bessel function of the first kind of order 1.
- Parameters
- xarray_like
Argument (float)
- Returns
- Indarray
Value of the modified Bessel function of order 1 at x.
Notes
The range is partitioned into the two intervals [0, 8] and (8, infinity). Chebyshev polynomial expansions are employed in each interval.
This function is a wrapper for the Cephes [1] routine
i1.References
- 1
Cephes Mathematical Functions Library, http://www.netlib.org/cephes/