def calculate_lanczos_kernel(x, a, window):
"""
Helper function to get the actually used kernel for a specific value of
a. Useful to analyse the behaviour of different tapers and different values
of a.
:type x: :class:`numpy.ndarray`
:param x: The x values at which to calculate the kernel.
:type a: int
:param a: The width of the window in samples on either side.
:type window: str
:param window: The window used to multiply the sinc function with. One
of ``"lanczos"``, ``"hanning"``, ``"blackman"``.
Returns a dictionary of arrays:
* ``"full_kernel"``: The tapered sinc function evaluated at samples ``x``.
* ``"only_sinc"``: The sinc function evaluated at samples ``x``.
* ``"only_taper"``: The taper function evaluated at samples ``x``.
"""
window = window.lower()
if window not in _LANCZOS_KERNEL_MAP:
msg = "Invalid window. Valid windows: %s" % ", ".join(
sorted(_LANCZOS_KERNEL_MAP.keys()))
raise ValueError(msg)
x = np.require(x, dtype=np.float64)
y0 = np.zeros(x.shape, dtype=np.float64)
y1 = np.zeros(x.shape, dtype=np.float64)
y2 = np.zeros(x.shape, dtype=np.float64)
clibsignal.calculate_kernel(
x, y0, len(x), a, 0, _LANCZOS_KERNEL_MAP[window])
clibsignal.calculate_kernel(
x, y1, len(x), a, 1, _LANCZOS_KERNEL_MAP[window])
clibsignal.calculate_kernel(
x, y2, len(x), a, 2, _LANCZOS_KERNEL_MAP[window])
ret_val = {
"full_kernel": y0,
"only_sinc": y1,
"only_taper": y2
}
return ret_val
def calculate_lanczos_kernel(x, a, window):
"""
Helper function to get the actually used kernel for a specific value of
a. Useful to analyse the behaviour of different tapers and different values
of a.
:type x: :class:`numpy.ndarray`
:param x: The x values at which to calculate the kernel.
:type a: int
:param a: The width of the window in samples on either side.
:type window: str
:param window: The window used to multiply the sinc function with. One
of ``"lanczos"``, ``"hanning"``, ``"blackman"``.
Returns a dictionary of arrays:
* ``"full_kernel"``: The tapered sinc function evaluated at samples ``x``.
* ``"only_sinc"``: The sinc function evaluated at samples ``x``.
* ``"only_taper"``: The taper function evaluated at samples ``x``.
"""
window = window.lower()
if window not in _LANCZOS_KERNEL_MAP:
msg = "Invalid window. Valid windows: %s" % ", ".join(
sorted(_LANCZOS_KERNEL_MAP.keys()))
raise ValueError(msg)
x = np.require(x, dtype=np.float64)
y0 = np.zeros(x.shape, dtype=np.float64)
y1 = np.zeros(x.shape, dtype=np.float64)
y2 = np.zeros(x.shape, dtype=np.float64)
clibsignal.calculate_kernel(
x, y0, len(x), a, 0, _LANCZOS_KERNEL_MAP[window])
clibsignal.calculate_kernel(
x, y1, len(x), a, 1, _LANCZOS_KERNEL_MAP[window])
clibsignal.calculate_kernel(
x, y2, len(x), a, 2, _LANCZOS_KERNEL_MAP[window])
ret_val = {
"full_kernel": y0,
"only_sinc": y1,
"only_taper": y2
}
return ret_val