summaryrefslogtreecommitdiff
path: root/lib/pelt.py
blob: 8966d56dde1d768a3ce174606becd6b9fbbc1850 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
import numpy as np
from multiprocessing import Pool


def PELT_get_changepoints(algo, penalty):
    res = (penalty, algo.predict(pen=penalty))
    return res


# calculates the raw_states for measurement measurement. num_measurement is used to identify the
# return value
# penalty, model and jump are directly passed to pelt
def PELT_get_raw_states(num_measurement, algo, signal, penalty):
    bkpts = algo.predict(pen=penalty)
    calced_states = list()
    start_time = 0
    end_time = 0
    # calc metrics for all states
    for bkpt in bkpts:
        # start_time of state is end_time of previous one
        # (Transitions are instantaneous)
        start_time = end_time
        end_time = bkpt
        power_vals = signal[start_time:end_time]
        mean_power = np.mean(power_vals)
        std_dev = np.std(power_vals)
        calced_state = (start_time, end_time, mean_power, std_dev)
        calced_states.append(calced_state)
    num = 0
    new_avg_std = 0
    # calc avg std for all states from this measurement
    for s in calced_states:
        # print_info("State " + str(num) + " starts at t=" + str(s[0])
        #            + " and ends at t=" + str(s[1])
        #            + " while using " + str(s[2])
        #            + "uW with  sigma=" + str(s[3]))
        num = num + 1
        new_avg_std = new_avg_std + s[3]
    # check case if no state has been found to avoid crashing
    if len(calced_states) != 0:
        new_avg_std = new_avg_std / len(calced_states)
    else:
        new_avg_std = 0
    change_avg_std = None  # measurement["uW_std"] - new_avg_std
    # print_info("The average standard deviation for the newly found states is "
    #            + str(new_avg_std))
    # print_info("That is a reduction of " + str(change_avg_std))
    return num_measurement, calced_states, new_avg_std, change_avg_std


class PELT:
    def __init__(self, **kwargs):
        self.model = "l1"
        self.jump = 1
        self.min_dist = 10
        self.num_samples = None
        self.refinement_threshold = 200e-6  # µW
        self.range_min = 0
        self.range_max = 100
        self.__dict__.update(kwargs)

    # signals: a set of uW measurements belonging to a single parameter configuration (i.e., a single by_param entry)
    def needs_refinement(self, signals):
        count = 0
        for signal in signals:
            # test
            p1, median, p99 = np.percentile(signal[5:-5], (1, 50, 99))

            if median - p1 > self.refinement_threshold:
                count += 1
            elif p99 - median > self.refinement_threshold:
                count += 1
        refinement_ratio = count / len(signals)
        return refinement_ratio > 0.3

    def norm_signal(self, signal, scaler=25):
        max_val = max(np.abs(signal))
        normed_signal = np.zeros(shape=len(signal))
        for i, signal_i in enumerate(signal):
            normed_signal[i] = signal_i / max_val
            normed_signal[i] = normed_signal[i] * scaler
        return normed_signal

    def get_penalty_and_changepoints(self, signal):
        # imported here as ruptures is only used for changepoint detection.
        # This way, dfatool can be used without having ruptures installed as
        # long as --pelt isn't active.
        import ruptures

        if self.num_samples is not None:
            self.jump = len(signal) // int(self.num_samples)
        else:
            self.jump = 1

        algo = ruptures.Pelt(
            model=self.model, jump=self.jump, min_size=self.min_dist
        ).fit(self.norm_signal(signal))
        queue = list()
        for i in range(0, 100):
            queue.append((algo, i))
        with Pool() as pool:
            changepoints = pool.starmap(PELT_get_changepoints, queue)
        changepoints_by_penalty = dict()
        for res in changepoints:
            if len(res[1]) > 0 and res[1][-1] == len(signal):
                res[1].pop()
            changepoints_by_penalty[res[0]] = res[1]
        num_changepoints = list()
        for i in range(0, 100):
            num_changepoints.append(len(changepoints_by_penalty[i]))

        start_index = -1
        end_index = -1
        longest_start = -1
        longest_end = -1
        prev_val = -1
        for i, num_bkpts in enumerate(num_changepoints):
            if num_bkpts != prev_val:
                end_index = i - 1
                if end_index - start_index > longest_end - longest_start:
                    longest_start = start_index
                    longest_end = end_index
                start_index = i
            if i == len(num_changepoints) - 1:
                end_index = i
                if end_index - start_index > longest_end - longest_start:
                    longest_start = start_index
                    longest_end = end_index
                start_index = i
            prev_val = num_bkpts
        middle_of_plateau = longest_start + (longest_start - longest_start) // 2
        changepoints = np.array(changepoints_by_penalty[middle_of_plateau])
        return middle_of_plateau, changepoints

    def get_changepoints(self, signal):
        _, changepoints = self.get_penalty_and_changepoints(signal)
        return changepoints

    def get_penalty(self, signal):
        penalty, _ = self.get_penalty_and_changepoints(signal)
        return penalty

    def calc_raw_states(self, signals, penalty, opt_model=None):
        # imported here as ruptures is only used for changepoint detection.
        # This way, dfatool can be used without having ruptures installed as
        # long as --pelt isn't active.
        import ruptures

        raw_states_calc_args = list()
        for num_measurement, measurement in enumerate(signals):
            normed_signal = self.norm_signal(measurement)
            algo = ruptures.Pelt(
                model=self.model, jump=self.jump, min_size=self.min_dist
            ).fit(normed_signal)
            raw_states_calc_args.append((num_measurement, algo, normed_signal, penalty))

        raw_states_list = [None] * len(signals)
        with Pool() as pool:
            raw_states_res = pool.starmap(PELT_get_raw_states, raw_states_calc_args)

        # extracting result and putting it in correct order -> index of raw_states_list
        # entry still corresponds with index of measurement in measurements_by_states
        # -> If measurements are discarded the used ones are easily recognized
        for ret_val in raw_states_res:
            num_measurement = ret_val[0]
            raw_states = ret_val[1]
            avg_std = ret_val[2]
            change_avg_std = ret_val[3]
            # FIXME: Wieso gibt mir meine IDE hier eine Warning aus? Der Index müsste doch
            #   int sein oder nicht? Es scheint auch vernünftig zu klappen...
            raw_states_list[num_measurement] = raw_states
            # print(
            #    "The average standard deviation for the newly found states in "
            #    + "measurement No. "
            #    + str(num_measurement)
            #    + " is "
            #    + str(avg_std)
            # )
            # print("That is a reduction of " + str(change_avg_std))
            for i, raw_state in enumerate(raw_states):
                print(
                    f"Measurement #{num_measurement} sub-state #{i}: {raw_state[0]} -> {raw_state[1]}, mean {raw_state[2]}"
                )
            # l_signal = measurements_by_config['offline'][num_measurement]['uW']
            # l_bkpts = [s[1] for s in raw_states]
            # fig, ax = rpt.display(np.array(l_signal), l_bkpts)
            # plt.show()