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62 lines
2.0 KiB
62 lines
2.0 KiB
6 years ago
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import numpy as np
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def is_intersect(target_segment, segments):
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for segment in segments:
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start = max(segment['start'], target_segment[0])
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finish = min(segment['finish'], target_segment[1])
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if start <= finish:
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return True
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return False
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def exponential_smoothing(series, alpha):
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result = [series[0]]
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for n in range(1, len(series)):
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result.append(alpha * series[n] + (1 - alpha) * result[n - 1])
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return result
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def find_steps(array, threshold):
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"""
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Finds local maxima by segmenting array based on positions at which
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the threshold value is crossed. Note that this thresholding is
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applied after the absolute value of the array is taken. Thus,
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the distinction between upward and downward steps is lost. However,
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get_step_sizes can be used to determine directionality after the
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fact.
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Parameters
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----------
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array : numpy array
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1 dimensional array that represents time series of data points
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threshold : int / float
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Threshold value that defines a step
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Returns
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-------
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steps : list
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List of indices of the detected steps
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"""
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steps = []
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array = np.abs(array)
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above_points = np.where(array > threshold, 1, 0)
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ap_dif = np.diff(above_points)
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cross_ups = np.where(ap_dif == 1)[0]
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cross_dns = np.where(ap_dif == -1)[0]
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for upi, dni in zip(cross_ups,cross_dns):
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steps.append(np.argmax(array[upi:dni]) + upi)
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return steps
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def anomalies_to_timestamp(anomalies):
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for anomaly in anomalies:
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anomaly['start'] = int(anomaly['start'].timestamp() * 1000)
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anomaly['finish'] = int(anomaly['finish'].timestamp() * 1000)
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return anomalies
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def segments_box(segments):
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max_time = 0
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min_time = float("inf")
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for segment in segments:
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min_time = min(min_time, segment['start'])
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max_time = max(max_time, segment['finish'])
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min_time = pd.to_datetime(min_time, unit='ms')
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max_time = pd.to_datetime(max_time, unit='ms')
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return min_time, max_time
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