summaryrefslogtreecommitdiff
path: root/lib/automata.py
blob: 3d62735ddbf8e3a2637398fdd46b897106310ce9 (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
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
"""Classes and helper functions for PTA and other automata."""

from functions import AnalyticFunction, NormalizationFunction
from utils import is_numeric
import itertools
import numpy as np
import json
import yaml


def _dict_to_list(input_dict: dict) -> list:
    return [input_dict[x] for x in sorted(input_dict.keys())]


def _attribute_to_json(static_value: float, param_function: AnalyticFunction) -> dict:
    ret = {
        'static': static_value
    }
    if param_function:
        ret['function'] = {
            'raw': param_function._model_str,
            'regression_args': list(param_function._regression_args)
        }
    return ret


class State:
    """A single PTA state."""

    def __init__(self, name: str, power: float = 0, power_function: AnalyticFunction = None):
        u"""
        Create a new PTA state.

        :param name: state name
        :param power: static state power in µW
        :param power_function: parameterized state power in µW
        """
        self.name = name
        self.power = power
        self.power_function = power_function
        self.outgoing_transitions = {}

    def add_outgoing_transition(self, new_transition: object):
        """Add a new outgoing transition."""
        self.outgoing_transitions[new_transition.name] = new_transition

    def get_energy(self, duration: float, param_dict: dict = {}) -> float:
        u"""
        Return energy spent in state in pJ.

        :param duration: duration in µs
        :param param_dict: current parameters
        :returns: energy spent in pJ
        """
        if self.power_function:
            return self.power_function.eval(_dict_to_list(param_dict)) * duration
        return self.power * duration

    def set_random_energy_model(self, static_model=True):
        """Set a random static energy value."""
        self.power = int(np.random.sample() * 50000)

    def get_transition(self, transition_name: str) -> object:
        """
        Return Transition object for outgoing transtion transition_name.

        :param transition_name: transition name
        :returns: `Transition` object
        """
        return self.outgoing_transitions[transition_name]

    def has_interrupt_transitions(self) -> bool:
        """Check whether this state has any outgoing interrupt transitions."""
        for trans in self.outgoing_transitions.values():
            if trans.is_interrupt:
                return True
        return False

    def get_next_interrupt(self, parameters: dict) -> object:
        """
        Return the outgoing interrupt transition with the lowet timeout.

        Must only be called if has_interrupt_transitions returned true.

        :param parameters: current parameter values
        :returns: Transition object
        """
        interrupts = filter(lambda x: x.is_interrupt, self.outgoing_transitions.values())
        interrupts = sorted(interrupts, key=lambda x: x.get_timeout(parameters))
        return interrupts[0]

    def dfs(self, depth: int, with_arguments=False, trace_filter=None, sleep=0):
        """
        Return a generator object for depth-first search over all outgoing transitions.

        :param depth: search depth
        :param with_arguments: perform dfs with function+argument transitions instead of just function transitions.
        :param trace_filter: list of lists. Each sub-list is a trace. Only traces matching one of the provided sub-lists are returned.
            E.g. trace_filter = [['init', 'foo'], ['init', 'bar']] will only return traces with init as first and foo or bar as second element.
            trace_filter = [['init', 'foo', '$'], ['init', 'bar', '$']] will only return the traces ['init', 'foo'] and ['init', 'bar'].
            Note that `trace_filter` takes precedence over `depth`: traces matching `trace_filter` are generated even if their length exceeds `depth`
        :param sleep: if set and non-zero: include sleep pseudo-states with <sleep> us duration
            For the [['init', 'foo', '$'], ['init', 'bar', '$']] example above, sleep=10 results in [(None, 10), 'init', (None, 10), 'foo'] and [(None, 10), 'init', (None, 10), 'bar']
        :returns: Generator object for depth-first search. Each access yields a list of (Transition, (arguments)) elements describing a single run through the PTA.
        """

        # TODO parametergewahrer Trace-Filter, z.B. "setHeaterDuration nur wenn bme680 power mode => FORCED und GAS_ENABLED"

        # A '$' entry in trace_filter indicates that the trace should (successfully) terminate here regardless of `depth`.
        if trace_filter is not None and next(filter(lambda x: x == '$', map(lambda x: x[0], trace_filter)), None) is not None:
            yield []
        # there may be other entries in trace_filter that still yield results.
        if depth == 0:
            for trans in self.outgoing_transitions.values():
                if trace_filter is not None and len(list(filter(lambda x: x == trans.name, map(lambda x: x[0], trace_filter)))) == 0:
                    continue
                if with_arguments:
                    if trans.argument_combination == 'cartesian':
                        for args in itertools.product(*trans.argument_values):
                            if sleep:
                                yield [(None, sleep), (trans, args)]
                            else:
                                yield [(trans, args)]
                    else:
                        for args in zip(*trans.argument_values):
                            if sleep:
                                yield [(None, sleep), (trans, args)]
                            else:
                                yield [(trans, args)]
                else:
                    if sleep:
                        yield [(None, sleep), (trans,)]
                    else:
                        yield [(trans,)]
        else:
            for trans in self.outgoing_transitions.values():
                if trace_filter is not None and next(filter(lambda x: x == trans.name, map(lambda x: x[0], trace_filter)), None) is None:
                    continue
                if trace_filter is not None:
                    new_trace_filter = map(lambda x: x[1:], filter(lambda x: x[0] == trans.name, trace_filter))
                    new_trace_filter = list(filter(len, new_trace_filter))
                    if len(new_trace_filter) == 0:
                        new_trace_filter = None
                else:
                    new_trace_filter = None
                for suffix in trans.destination.dfs(depth - 1, with_arguments=with_arguments, trace_filter=new_trace_filter, sleep=sleep):
                    if with_arguments:
                        if trans.argument_combination == 'cartesian':
                            for args in itertools.product(*trans.argument_values):
                                if sleep:
                                    new_suffix = [(None, sleep), (trans, args)]
                                else:
                                    new_suffix = [(trans, args)]
                                new_suffix.extend(suffix)
                                yield new_suffix
                        else:
                            if len(trans.argument_values):
                                arg_values = zip(*trans.argument_values)
                            else:
                                arg_values = [tuple()]
                            for args in arg_values:
                                if sleep:
                                    new_suffix = [(None, sleep), (trans, args)]
                                else:
                                    new_suffix = [(trans, args)]
                                new_suffix.extend(suffix)
                                yield new_suffix
                    else:
                        if sleep:
                            new_suffix = [(None, sleep), (trans,)]
                        else:
                            new_suffix = [(trans,)]
                        new_suffix.extend(suffix)
                        yield new_suffix

    def to_json(self) -> dict:
        """Return JSON encoding of this state object."""
        ret = {
            'name': self.name,
            'power': _attribute_to_json(self.power, self.power_function)
        }
        return ret


class Transition:
    u"""
    A single PTA transition with one origin and one destination state.

    :param name: transition name, corresponds to driver function name
    :param origin: origin `State`
    :param destination: destination `State`
    :param energy: static energy needed to execute this transition, in pJ
    :param energy_function: parameterized transition energy `AnalyticFunction`, returning pJ
    :param duration: transition duration, in µs
    :param duration_function: parameterized duration `AnalyticFunction`, returning µs
    :param timeout: transition timeout, in µs. Only set for interrupt transitions.
    :param timeout_function: parameterized transition timeout `AnalyticFunction`, in µs. Only set for interrupt transitions.
    :param is_interrupt: Is this an interrupt transition?
    :param arguments: list of function argument names
    :param argument_values: list of argument values used for benchmark generation. Each entry is a list of values for the corresponding argument
    :param argument_combination: During benchmark generation, should arguments be combined via `cartesian` or `zip`?
    :param param_update_function: Setter for parameters after a transition. Gets current parameter dict and function argument values as arguments, must return the new parameter dict
    :param arg_to_param_map: dict mapping argument index to the name of the parameter affected by its value
    :param set_param: dict mapping parameter name to their value (set as side-effect of executing the transition, not parameter-dependent)
    :param return_value_handlers: todo
    :param codegen: todo
    """

    def __init__(self, orig_state: State, dest_state: State, name: str,
                 energy: float = 0, energy_function: AnalyticFunction = None,
                 duration: float = 0, duration_function: AnalyticFunction = None,
                 timeout: float = 0, timeout_function: AnalyticFunction = None,
                 is_interrupt: bool = False,
                 arguments: list = [],
                 argument_values: list = [],
                 argument_combination: str = 'cartesian',  # or 'zip'
                 param_update_function=None,
                 arg_to_param_map: dict = None,
                 set_param=None,
                 return_value_handlers: list = [],
                 codegen=dict()):
        """
        Create a new transition between two PTA states.

        :param orig_state: origin `State`
        :param dest_state: destination `State`
        :param name: transition name, typically the same as a driver/library function name
        """
        self.name = name
        self.origin = orig_state
        self.destination = dest_state
        self.energy = energy
        self.energy_function = energy_function
        self.duration = duration
        self.duration_function = duration_function
        self.timeout = timeout
        self.timeout_function = timeout_function
        self.is_interrupt = is_interrupt
        self.arguments = arguments.copy()
        self.argument_values = argument_values.copy()
        self.argument_combination = argument_combination
        self.param_update_function = param_update_function
        self.arg_to_param_map = arg_to_param_map
        self.set_param = set_param
        self.return_value_handlers = return_value_handlers
        self.codegen = codegen

        for handler in self.return_value_handlers:
            if 'formula' in handler:
                handler['formula'] = NormalizationFunction(handler['formula'])

    def get_duration(self, param_dict: dict = {}, args: list = []) -> float:
        u"""
        Return transition duration in µs.

        :param param_dict: current parameter values
        :param args: function arguments

        :returns: transition duration in µs
        """
        if self.duration_function:
            return self.duration_function.eval(_dict_to_list(param_dict), args)
        return self.duration

    def get_energy(self, param_dict: dict = {}, args: list = []) -> float:
        u"""
        Return transition energy cost in pJ.

        :param param_dict: current parameter values
        :param args: function arguments
        """
        if self.energy_function:
            return self.energy_function.eval(_dict_to_list(param_dict), args)
        return self.energy

    def set_random_energy_model(self, static_model=True):
        self.energy = int(np.random.sample() * 50000)

    def get_timeout(self, param_dict: dict = {}) -> float:
        u"""
        Return transition timeout in µs.

        Returns 0 if the transition does not have a timeout.

        :param param_dict: current parameter values
        :param args: function arguments
        """
        if self.timeout_function:
            return self.timeout_function.eval(_dict_to_list(param_dict))
        return self.timeout

    def get_params_after_transition(self, param_dict: dict, args: list = []) -> dict:
        """
        Return the new parameter dict after taking this transition.

        parameter values may be affected by this transition's update function,
        it's argument-to-param map, and its set_param settings.

        Does not normalize parameter values.
        """
        if self.param_update_function:
            return self.param_update_function(param_dict, args)
        ret = param_dict.copy()
        if self.arg_to_param_map:
            for k, v in self.arg_to_param_map.items():
                ret[v] = args[k]
        if self.set_param:
            for k, v in self.set_param.items():
                ret[k] = v
        return ret

    def to_json(self) -> dict:
        """Return JSON encoding of this transition object."""
        ret = {
            'name': self.name,
            'origin': self.origin.name,
            'destination': self.destination.name,
            'is_interrupt': self.is_interrupt,
            'arguments': self.arguments,
            'argument_values': self.argument_values,
            'argument_combination': self.argument_combination,
            'arg_to_param_map': self.arg_to_param_map,
            'set_param': self.set_param,
            'duration': _attribute_to_json(self.duration, self.duration_function),
            'energy': _attribute_to_json(self.energy, self.energy_function),
            'timeout': _attribute_to_json(self.timeout, self.timeout_function),
        }
        return ret


def _json_function_to_analytic_function(base, attribute: str, parameters: list):
    if attribute in base and 'function' in base[attribute]:
        base = base[attribute]['function']
        return AnalyticFunction(base['raw'], parameters, 0, regression_args=base['regression_args'])
    return None


def _json_get_static(base, attribute: str):
    if attribute in base:
        return base[attribute]['static']
    return 0


class PTA:
    """
    A parameterized priced timed automaton.

    Suitable for simulation, model storage, and (soon) benchmark generation.

    :param state: dict mapping state name to `State` object
    :param accepting_states: list of accepting state names
    :param parameters: current parameters
    :param parameter_normalization:  dict mapping driver API parameter values to hardware values, e.g. a bitrate register value to an actual bitrate in kbit/s.
            Each parameter key has in turn a dict value. Supported entries:
            `enum`: Mapping of enum descriptors (eys) to parameter values. Note that the mapping is not required to correspond to the driver API.
            `formula`: NormalizationFunction mapping an argument or return value (passed as `param`) to a parameter value.
    :param codegen: TODO
    :param initial_param_values: TODO
    :param transitions: list of `Transition` objects
    """

    def __init__(self, state_names: list = [],
                 accepting_states: list = None,
                 parameters: list = [], initial_param_values: list = None,
                 codegen: dict = {}, parameter_normalization: dict = None):
        """
        Return a new PTA object.

        :param state_names: names of PTA states. Note that the PTA always contains
            an initial UNINITIALIZED state, regardless of the content of state_names.
        :param accepting_states: names of accepting states. By default, all states are accepting
        :param parameters: names of PTA parameters
        :param initial_param_values: initial value for each parameter
        :param instance: class used for generated C++ code
        :param header: header include path for C++ class definition
        :param parameter_normalization: dict mapping driver API parameter values to hardware values, e.g. a bitrate register value to an actual bitrate in kbit/s.
            Each parameter key has in turn a dict value. Supported entries:
            `enum`: maps enum descriptors (keys) to parameter values. Note that the mapping is not required to correspond to the driver API.
            `formula`: maps an argument or return value (passed as `param`) to a parameter value. Must be a string describing a valid python lambda function. NumPy is available as `np`.
        """
        self.state = dict([[state_name, State(state_name)] for state_name in state_names])
        self.accepting_states = accepting_states.copy() if accepting_states else None
        self.parameters = parameters.copy()
        self.parameter_normalization = parameter_normalization
        self.codegen = codegen
        if initial_param_values:
            self.initial_param_values = initial_param_values.copy()
        else:
            self.initial_param_values = [None for x in self.parameters]
        self.transitions = []

        if 'UNINITIALIZED' not in state_names:
            self.state['UNINITIALIZED'] = State('UNINITIALIZED')

        if self.parameter_normalization:
            for normalization_spec in self.parameter_normalization.values():
                if 'formula' in normalization_spec:
                    normalization_spec['formula'] = NormalizationFunction(normalization_spec['formula'])

    def normalize_parameter(self, parameter_name: str, parameter_value) -> float:
        """
        Return normalized parameter.

        Normalization refers to anything specified in the model's `parameter_normalization` section,
        e.g. enum -> int translation or argument -> parameter value formulas.

        :param parameter_name: parameter name.
        :param parameter_value: parameter value.
        """
        if parameter_value is not None and self.parameter_normalization is not None and parameter_name in self.parameter_normalization:
            if 'enum' in self.parameter_normalization[parameter_name] and parameter_value in self.parameter_normalization[parameter_name]['enum']:
                return self.parameter_normalization[parameter_name]['enum'][parameter_value]
            if 'formula' in self.parameter_normalization[parameter_name]:
                normalization_formula = self.parameter_normalization[parameter_name]['formula']
                return normalization_formula.eval(parameter_value)
        return parameter_value

    def normalize_parameters(self, param_dict) -> dict:
        """
        Return normalized parameters.

        Normalization refers to anything specified in the model's `parameter_normalization` section,
        e.g. enum -> int translation or argument -> parameter value formulas.

        :param param_dict: non-normalized parameters.
        """
        if self.parameter_normalization is None:
            return param_dict.copy()
        normalized_param = param_dict.copy()
        for parameter, value in param_dict.items():
            normalized_param[parameter] = self.normalize_parameter(parameter, value)
        return normalized_param

    @classmethod
    def from_file(cls, model_file: str):
        """Return PTA loaded from the provided JSON or YAML file."""
        with open(model_file, 'r') as f:
            if '.json' in model_file:
                return cls.from_json(json.load(f))
            else:
                return cls.from_yaml(yaml.safe_load(f))

    @classmethod
    def from_json(cls, json_input: dict):
        """
        Return a PTA created from the provided JSON data.

        Compatible with the to_json method.
        """
        if 'transition' in json_input:
            return cls.from_legacy_json(json_input)

        kwargs = dict()
        for key in ('state_names', 'parameters', 'initial_param_values', 'accepting_states'):
            if key in json_input:
                kwargs[key] = json_input[key]
        pta = cls(**kwargs)
        for name, state in json_input['state'].items():
            power_function = _json_function_to_analytic_function(state, 'power', pta.parameters)
            pta.add_state(name, power=_json_get_static(state, 'power'), power_function=power_function)
        for transition in json_input['transitions']:
            duration_function = _json_function_to_analytic_function(transition, 'duration', pta.parameters)
            energy_function = _json_function_to_analytic_function(transition, 'energy', pta.parameters)
            timeout_function = _json_function_to_analytic_function(transition, 'timeout', pta.parameters)
            kwargs = dict()
            for key in ['arg_to_param_map', 'argument_values', 'argument_combination']:
                if key in transition:
                    kwargs[key] = transition[key]
            origins = transition['origin']
            if type(origins) != list:
                origins = [origins]
            for origin in origins:
                pta.add_transition(origin, transition['destination'],
                                   transition['name'],
                                   duration=_json_get_static(transition, 'duration'),
                                   duration_function=duration_function,
                                   energy=_json_get_static(transition, 'energy'),
                                   energy_function=energy_function,
                                   timeout=_json_get_static(transition, 'timeout'),
                                   timeout_function=timeout_function,
                                   **kwargs)

        return pta

    @classmethod
    def from_legacy_json(cls, json_input: dict):
        """
        Return a PTA created from the provided JSON data.

        Compatible with the legacy dfatool/perl format.
        """
        kwargs = {
            'parameters': list(),
            'initial_param_values': list(),
        }

        for param in sorted(json_input['parameter'].keys()):
            kwargs['parameters'].append(param)
            kwargs['initial_param_values'].append(json_input['parameter'][param]['default'])

        pta = cls(**kwargs)

        for name, state in json_input['state'].items():
            pta.add_state(name, power=float(state['power']['static']))

        for trans_name in sorted(json_input['transition'].keys()):
            transition = json_input['transition'][trans_name]
            destination = transition['destination']
            arguments = list()
            argument_values = list()
            is_interrupt = False
            if transition['level'] == 'epilogue':
                is_interrupt = True
            if type(destination) == list:
                destination = destination[0]
            for arg in transition['parameters']:
                arguments.append(arg['name'])
                argument_values.append(arg['values'])
            for origin in transition['origins']:
                pta.add_transition(origin, destination, trans_name,
                                   arguments=arguments,
                                   argument_values=argument_values,
                                   is_interrupt=is_interrupt)

        return pta

    @classmethod
    def from_yaml(cls, yaml_input: dict):
        """Return a PTA created from the YAML DFA format (passed as dict)."""

        kwargs = dict()

        if 'parameters' in yaml_input:
            kwargs['parameters'] = yaml_input['parameters']

        if 'initial_param_values' in yaml_input:
            kwargs['initial_param_values'] = yaml_input['initial_param_values']

        if 'states' in yaml_input:
            kwargs['state_names'] = yaml_input['states']
        # else: set to UNINITIALIZED by class constructor

        if 'codegen' in yaml_input:
            kwargs['codegen'] = yaml_input['codegen']

        if 'parameter_normalization' in yaml_input:
            kwargs['parameter_normalization'] = yaml_input['parameter_normalization']

        pta = cls(**kwargs)

        for trans_name in sorted(yaml_input['transition'].keys()):
            kwargs = dict()
            transition = yaml_input['transition'][trans_name]
            arguments = list()
            argument_values = list()
            arg_to_param_map = dict()
            if 'arguments' in transition:
                for i, argument in enumerate(transition['arguments']):
                    arguments.append(argument['name'])
                    argument_values.append(argument['values'])
                    if 'parameter' in argument:
                        arg_to_param_map[i] = argument['parameter']
            if 'argument_combination' in transition:
                kwargs['argument_combination'] = transition['argument_combination']
            if 'set_param' in transition:
                kwargs['set_param'] = transition['set_param']
            if 'is_interrupt' in transition:
                kwargs['is_interrupt'] = transition['is_interrupt']
            if 'return_value' in transition:
                kwargs['return_value_handlers'] = transition['return_value']
            if 'loop' in transition:
                for state_name in transition['loop']:
                    pta.add_transition(state_name, state_name, trans_name,
                                       arguments=arguments,
                                       argument_values=argument_values,
                                       arg_to_param_map=arg_to_param_map,
                                       **kwargs)
            else:
                if 'src' not in transition:
                    transition['src'] = ['UNINITIALIZED']
                if 'dst' not in transition:
                    transition['dst'] = 'UNINITIALIZED'
                for origin in transition['src']:
                    pta.add_transition(origin, transition['dst'], trans_name,
                                       arguments=arguments,
                                       argument_values=argument_values,
                                       arg_to_param_map=arg_to_param_map,
                                       **kwargs)

        return pta

    def to_json(self) -> dict:
        """
        Return JSON encoding of this PTA.

        Compatible with the from_json method.
        """
        ret = {
            'parameters': self.parameters,
            'initial_param_values': self.initial_param_values,
            'state': dict([[state.name, state.to_json()] for state in self.state.values()]),
            'transitions': [trans.to_json() for trans in self.transitions],
            'accepting_states': self.accepting_states,
        }
        return ret

    def add_state(self, state_name: str, **kwargs):
        """
        Add a new state.

        See the State() documentation for acceptable arguments.
        """
        if 'power_function' in kwargs and type(kwargs['power_function']) != AnalyticFunction and kwargs['power_function'] is not None:
            kwargs['power_function'] = AnalyticFunction(kwargs['power_function'],
                                                        self.parameters, 0)
        self.state[state_name] = State(state_name, **kwargs)

    def add_transition(self, orig_state: str, dest_state: str, function_name: str, **kwargs):
        """
        Add function_name as new transition from orig_state to dest_state.

        arguments:
        orig_state -- origin state name. Must be known to PTA
        dest_state -- destination state name. Must be known to PTA.
        function_name -- function name
        kwargs -- see Transition() documentation
        """
        orig_state = self.state[orig_state]
        dest_state = self.state[dest_state]
        for key in ('duration_function', 'energy_function', 'timeout_function'):
            if key in kwargs and kwargs[key] is not None and type(kwargs[key]) != AnalyticFunction:
                kwargs[key] = AnalyticFunction(kwargs[key], self.parameters, 0)

        new_transition = Transition(orig_state, dest_state, function_name, **kwargs)
        self.transitions.append(new_transition)
        orig_state.add_outgoing_transition(new_transition)

    def get_transition_id(self, transition: Transition) -> int:
        """Return PTA-specific ID of transition."""
        return self.transitions.index(transition)

    def get_state_names(self):
        """Return lexically sorted list of PTA state names."""
        return sorted(self.state.keys())

    def get_state_id(self, state: State) -> int:
        """Return PTA-specific ID of state."""
        return self.get_state_names().index(state.name)

    def get_unique_transitions(self):
        """
        Return list of PTA transitions without duplicates.

        I.e., each transition name only occurs once, even if it has several entries due to
        multiple origin states and/or overloading.
        """
        seen_transitions = set()
        ret_transitions = list()
        for transition in self.transitions:
            if transition.name not in seen_transitions:
                ret_transitions.append(transition)
                seen_transitions.add(transition.name)
        return ret_transitions

    def get_unique_transition_id(self, transition: Transition) -> int:
        """
        Return PTA-specific ID of transition in unique transition list.

        The followinng condition holds:
        `
        max_index = max(map(lambda t: pta.get_unique_transition_id(t), pta.get_unique_transitions()))
        max_index == len(pta.get_unique_transitions) - 1
        `
        """
        return self.get_unique_transitions().index(transition)

    def get_initial_param_dict(self):
        return dict([[self.parameters[i], self.initial_param_values[i]] for i in range(len(self.parameters))])

    def set_random_energy_model(self, static_model=True):
        for state in self.state.values():
            state.set_random_energy_model(static_model)
        for transition in self.transitions:
            transition.set_random_energy_model(static_model)

    def shrink_argument_values(self):
        """
        Throw away all but two values for each numeric argument of each transition.

        This is meant to speed up an initial PTA-based benchmark by
        reducing the parameter space while still gaining insights in the
        effect (or nop) or individual parameters on hardware behaviour.

        Parameters with non-numeric values (anything containing neither
        numbers nor enums) are left as-is, as they may be distinct
        toggles whose effect cannot be estimated when they are left out.
        """
        for transition in self.transitions:
            for i, argument in enumerate(transition.arguments):
                if len(transition.argument_values[i]) <= 2:
                    continue
                if transition.argument_combination == 'zip':
                    continue
                values_are_numeric = True
                for value in transition.argument_values[i]:
                    if not is_numeric(self.normalize_parameter(transition.arg_to_param_map[i], value)):
                        values_are_numeric = False
                if values_are_numeric and len(transition.argument_values[i]) > 2:
                    transition.argument_values[i] = [transition.argument_values[i][0], transition.argument_values[i][-1]]

    def _dfs_with_param(self, generator, param_dict):
        for trace in generator:
            param = param_dict.copy()
            ret = list()
            for elem in trace:
                transition, arguments = elem
                if transition is not None:
                    param = transition.get_params_after_transition(param, arguments)
                    ret.append((transition, arguments, self.normalize_parameters(param)))
                else:
                    # parameters have already been normalized
                    ret.append((transition, arguments, param))
            yield ret

    def dfs(self, depth: int = 10, orig_state: str = 'UNINITIALIZED', param_dict: dict = None, with_parameters: bool = False, **kwargs):
        """
        Return a generator object for depth-first search starting at orig_state.

        :param depth: search depth
        :param orig_state: initial state for depth-first search
        :param param_dict: initial parameter values
        :param with_arguments: perform dfs with argument values
        :param with_parameters: include parameters in trace?
        :param trace_filter: list of lists. Each sub-list is a trace. Only traces matching one of the provided sub-lists are returned.
        :param sleep: sleep duration between states in us. If None or 0, no sleep pseudo-transitions will be included in the trace.

        The returned generator emits traces. Each trace consts of a list of
        tuples describing the corresponding transition and (if enabled)
        arguments and parameters. When both with_arguments and with_parameters
        are True, each transition is a (Transition object, argument list, parameter dict) tuple.

        Note that the parameter dict refers to parameter values _after_
        passing the corresponding transition. Although this may seem odd at
        first, it is useful when analyzing measurements: Properties of
        the state following this transition may be affected by the parameters
        set by the transition, so it is useful to have those readily available.
        """
        if with_parameters and not param_dict:
            param_dict = self.get_initial_param_dict()

        if with_parameters and 'with_arguments' not in kwargs:
            raise ValueError("with_parameters = True requires with_arguments = True")

        if self.accepting_states:
            generator = filter(lambda x: x[-1][0].destination.name in self.accepting_states,
                               self.state[orig_state].dfs(depth, **kwargs))
        else:
            generator = self.state[orig_state].dfs(depth, **kwargs)

        if with_parameters:
            return self._dfs_with_param(generator, param_dict)
        else:
            return generator

    def simulate(self, trace: list, orig_state: str = 'UNINITIALIZED', accounting=None):
        u"""
        Simulate a single run through the PTA and return total energy, duration, final state, and resulting parameters.

        :param trace: list of (function name, arg1, arg2, ...) tuples representing the individual transitions,
            or list of (Transition, argument tuple, parameter) tuples originating from dfs.
            The tuple (None, duration) represents a sleep time between states in us
        :param orig_state: origin state, default UNINITIALIZED

        :returns (total energy in pJ, total duration in µs, end state, end parameters)
        """
        total_duration = 0.
        total_energy = 0.
        state = self.state[orig_state]
        param_dict = dict([[self.parameters[i], self.initial_param_values[i]] for i in range(len(self.parameters))])
        for function in trace:
            if isinstance(function[0], Transition):
                function_name = function[0].name
                function_args = function[1]
            else:
                function_name = function[0]
                function_args = function[1:]
            if function_name is None:
                duration = function_args[0]
                total_energy += state.get_energy(duration, param_dict)
                total_duration += duration
                if accounting is not None:
                    accounting.sleep(duration)
            else:
                transition = state.get_transition(function_name)
                total_duration += transition.get_duration(param_dict, function_args)
                total_energy += transition.get_energy(param_dict, function_args)
                param_dict = transition.get_params_after_transition(param_dict, function_args)
                state = transition.destination
                if accounting is not None:
                    accounting.pass_transition(transition)
                while (state.has_interrupt_transitions()):
                    transition = state.get_next_interrupt(param_dict)
                    duration = transition.get_timeout(param_dict)
                    total_duration += duration
                    total_energy += state.get_energy(duration, param_dict)
                    if accounting is not None:
                        accounting.sleep(duration)
                        accounting.pass_transition(transition)
                    param_dict = transition.get_params_after_transition(param_dict)
                    state = transition.destination

        return total_energy, total_duration, state, param_dict

    def update(self, static_model, param_model):
        for state in self.state.values():
            if state.name != 'UNINITIALIZED':
                state.power = static_model(state.name, 'power')
                if param_model(state.name, 'power'):
                    state.power_function = param_model(state.name, 'power')['function']
        for transition in self.transitions:
            transition.duration = static_model(transition.name, 'duration')
            if param_model(transition.name, 'duration'):
                transition.duration_function = param_model(transition.name, 'duration')['function']
            transition.energy = static_model(transition.name, 'energy')
            if param_model(transition.name, 'energy'):
                transition.energy_function = param_model(transition.name, 'energy')['function']
            if transition.is_interrupt:
                transition.timeout = static_model(transition.name, 'timeout')
                if param_model(transition.name, 'timeout'):
                    transition.timeout_function = param_model(transition.name, 'timeout')['function']