30 lines
873 B
Python
30 lines
873 B
Python
import numpy as np
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from scipy.signal import convolve
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def _ricker(points, a):
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A = 2 / (np.sqrt(3 * a) * (np.pi**0.25))
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wsq = a**2
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vec = np.arange(0, points) - (points - 1.0) / 2
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xsq = vec**2
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mod = (1 - xsq / wsq)
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gauss = np.exp(-xsq / (2 * wsq))
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total = A * mod * gauss
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return total
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def _cwt(data, wavelet, widths, dtype=None, **kwargs):
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# Determine output type
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if dtype is None:
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if np.asarray(wavelet(1, widths[0], **kwargs)).dtype.char in 'FDG':
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dtype = np.complex128
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else:
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dtype = np.float64
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output = np.empty((len(widths), len(data)), dtype=dtype)
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for ind, width in enumerate(widths):
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N = np.min([10 * width, len(data)])
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wavelet_data = np.conj(wavelet(N, width, **kwargs)[::-1])
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output[ind] = convolve(data, wavelet_data, mode='same')
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return output
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