scipy.special.y0#
- scipy.special.y0(x, out=None) = <ufunc 'y0'>#
Bessel function of the second kind of order 0.
- Parameters:
- xarray_like
Argument (float).
- outndarray, optional
Optional output array for the function results
- Returns:
- Yscalar or ndarray
Value of the Bessel function of the second kind of order 0 at x.
Notes
The domain is divided into the intervals [0, 5] and (5, infinity). In the first interval a rational approximation \(R(x)\) is employed to compute,
\[Y_0(x) = R(x) + \frac{2 \log(x) J_0(x)}{\pi},\]where \(J_0\) is the Bessel function of the first kind of order 0.
In the second interval, the Hankel asymptotic expansion is employed with two rational functions of degree 6/6 and 7/7.
This function is a wrapper for the Cephes [1] routine
y0
.Array API Standard Support
y0
has experimental support for Python Array API Standard compatible backends in addition to NumPy. Please consider testing these features by setting an environment variableSCIPY_ARRAY_API=1
and providing CuPy, PyTorch, JAX, or Dask arrays as array arguments. The following combinations of backend and device (or other capability) are supported.Library
CPU
GPU
NumPy
✅
n/a
CuPy
n/a
✅
PyTorch
✅
✅
JAX
⚠️ no JIT
⛔
Dask
✅
n/a
See Support for the array API standard for more information.
References
[1]Cephes Mathematical Functions Library, http://www.netlib.org/cephes/
Examples
Calculate the function at one point:
>>> from scipy.special import y0 >>> y0(1.) 0.08825696421567697
Calculate at several points:
>>> import numpy as np >>> y0(np.array([0.5, 2., 3.])) array([-0.44451873, 0.51037567, 0.37685001])
Plot the function from 0 to 10.
>>> import matplotlib.pyplot as plt >>> fig, ax = plt.subplots() >>> x = np.linspace(0., 10., 1000) >>> y = y0(x) >>> ax.plot(x, y) >>> plt.show()