def classic_sta_lta(a, nsta, nlta):
"""
Computes the standard STA/LTA from a given input array a. The length of
the STA is given by nsta in samples, respectively is the length of the
LTA given by nlta in samples.
Fast version written in C.
:type a: NumPy :class:`~numpy.ndarray`
:param a: Seismic Trace
:type nsta: int
:param nsta: Length of short time average window in samples
:type nlta: int
:param nlta: Length of long time average window in samples
:rtype: NumPy :class:`~numpy.ndarray`
:return: Characteristic function of classic STA/LTA
"""
data = a
# initialize C struct / NumPy structured array
head = np.empty(1, dtype=head_stalta_t)
head[:] = (len(data), nsta, nlta)
# ensure correct type and contiguous of data
data = np.ascontiguousarray(data, dtype=np.float64)
# all memory should be allocated by python
charfct = np.empty(len(data), dtype=np.float64)
# run and check the error-code
errcode = clibsignal.stalta(head, data, charfct)
if errcode != 0:
raise Exception('ERROR %d stalta: len(data) < nlta' % errcode)
return charfct
def classicSTALTA(a, nsta, nlta):
"""
Computes the standard STA/LTA from a given input array a. The length of
the STA is given by nsta in samples, respectively is the length of the
LTA given by nlta in samples.
Fast version written in C.
:type a: NumPy ndarray
:param a: Seismic Trace
:type nsta: Int
:param nsta: Length of short time average window in samples
:type nlta: Int
:param nlta: Length of long time average window in samples
:rtype: NumPy ndarray
:return: Characteristic function of classic STA/LTA
"""
data = a
# initialize C struct / numpy structed array
head = np.empty(1, dtype=head_stalta_t)
head[:] = (len(data), nsta, nlta)
# ensure correct type and contiguous of data
data = np.require(data, dtype='f8', requirements=['C_CONTIGUOUS'])
# all memory should be allocated by python
charfct = np.empty(len(data), dtype='f8')
# run and check the error-code
errcode = clibsignal.stalta(head, data, charfct)
if errcode != 0:
raise Exception('ERROR %d stalta: len(data) < nlta' % errcode)
return charfct