transition_map.py 12.9 KB
Newer Older
1
2
3
4
5
"""
TransitionMap and derived classes.
"""

import numpy as np
6
from importlib_resources import path
7
from numpy import array
8

u214892's avatar
u214892 committed
9
from flatland.core.grid.grid4 import Grid4Transitions
u214892's avatar
u214892 committed
10
from flatland.core.transitions import Transitions
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


class TransitionMap:
    """
    Base TransitionMap class.

    Generic class that implements a collection of transitions over a set of
    cells.
    """

    def get_transitions(self, cell_id):
        """
        Return a tuple of transitions available in a cell specified by
        `cell_id' (e.g., a tuple of size of the maximum number of transitions,
        with values 0 or 1, or potentially in between,
        for stochastic transitions).

        Parameters
        ----------
        cell_id : [cell identifier]
            The cell_id object depends on the specific implementation.
            It generally is an int (e.g., an index) or a tuple of indices.

        Returns
        -------
        tuple
            List of the validity of transitions in the cell.

        """
        raise NotImplementedError()

    def set_transitions(self, cell_id, new_transitions):
        """
        Replaces the available transitions in cell `cell_id' with the tuple
        `new_transitions'. `new_transitions' must have
        one element for each possible transition.

        Parameters
        ----------
        cell_id : [cell identifier]
            The cell_id object depends on the specific implementation.
            It generally is an int (e.g., an index) or a tuple of indices.
        new_transitions : tuple
            Tuple of new transitions validitiy for the cell.

        """
        raise NotImplementedError()

    def get_transition(self, cell_id, transition_index):
        """
        Return the status of whether an agent in cell `cell_id' can perform a
        movement along transition `transition_index (e.g., the NESW direction
        of movement, for agents on a grid).

        Parameters
        ----------
        cell_id : [cell identifier]
            The cell_id object depends on the specific implementation.
            It generally is an int (e.g., an index) or a tuple of indices.
        transition_index : int
            Index of the transition to probe, as index in the tuple returned by
            get_transitions(). e.g., the NESW direction of movement, for agents
            on a grid.

        Returns
        -------
u214892's avatar
u214892 committed
77
        int or float (depending on Transitions used)
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
            Validity of the requested transition (e.g.,
            0/1 allowed/not allowed, a probability in [0,1], etc...)

        """
        raise NotImplementedError()

    def set_transition(self, cell_id, transition_index, new_transition):
        """
        Replaces the validity of transition to `transition_index' in cell
        `cell_id' with the new `new_transition'.


        Parameters
        ----------
        cell_id : [cell identifier]
            The cell_id object depends on the specific implementation.
            It generally is an int (e.g., an index) or a tuple of indices.
        transition_index : int
            Index of the transition to probe, as index in the tuple returned by
            get_transitions(). e.g., the NESW direction of movement, for agents
            on a grid.
u214892's avatar
u214892 committed
99
        new_transition : int or float (depending on Transitions used)
100
101
102
103
104
105
106
107
108
109
110
111
112
113
            Validity of the requested transition (e.g.,
            0/1 allowed/not allowed, a probability in [0,1], etc...)

        """
        raise NotImplementedError()


class GridTransitionMap(TransitionMap):
    """
    Implements a TransitionMap over a 2D grid.

    GridTransitionMap implements utility functions.
    """

u214892's avatar
u214892 committed
114
    def __init__(self, width, height, transitions: Transitions = Grid4Transitions([])):
115
116
117
118
119
120
121
122
123
        """
        Builder for GridTransitionMap object.

        Parameters
        ----------
        width : int
            Width of the grid.
        height : int
            Height of the grid.
124
        transitions : Transitions object
125
126
127
128
129
130
131
132
133
            The Transitions object to use to encode/decode transitions over the
            grid.

        """

        self.width = width
        self.height = height
        self.transitions = transitions

u214892's avatar
u214892 committed
134
        self.grid = np.zeros((height, width), dtype=self.transitions.get_type())
135

u214892's avatar
u214892 committed
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
    def get_full_transitions(self, row, column):
        """
        Returns the full transitions for the cell at (row, column) in the format transition_map's transitions.

        Parameters
        ----------
        row: int
        column: int
            (row,column) specifies the cell in this transition map.

        Returns
        -------
        self.transitions.get_type()
            The cell content int the format of this map's Transitions.

        """
        return self.grid[row][column]

    def get_transitions(self, row, column, orientation):
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
        """
        Return a tuple of transitions available in a cell specified by
        `cell_id' (e.g., a tuple of size of the maximum number of transitions,
        with values 0 or 1, or potentially in between,
        for stochastic transitions).

        Parameters
        ----------
        cell_id : tuple
            The cell_id indices a cell as (column, row, orientation),
            where orientation is the direction an agent is facing within a cell.
            Alternatively, it can be accessed as (column, row) to return the
            full cell content.

        Returns
        -------
        tuple
u214892's avatar
u214892 committed
172
            List of the validity of transitions in the cell as given by the maps transitions.
173
174

        """
u214892's avatar
u214892 committed
175
        return self.transitions.get_transitions(self.grid[row][column], orientation)
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193

    def set_transitions(self, cell_id, new_transitions):
        """
        Replaces the available transitions in cell `cell_id' with the tuple
        `new_transitions'. `new_transitions' must have
        one element for each possible transition.

        Parameters
        ----------
        cell_id : tuple
            The cell_id indices a cell as (column, row, orientation),
            where orientation is the direction an agent is facing within a cell.
            Alternatively, it can be accessed as (column, row) to replace the
            full cell content.
        new_transitions : tuple
            Tuple of new transitions validitiy for the cell.

        """
u214892's avatar
u214892 committed
194
195
        assert len(cell_id) in (2, 3), \
            'GridTransitionMap.set_transitions() ERROR: cell_id tuple must have length 2 or 3.'
196
        if len(cell_id) == 3:
spiglerg's avatar
spiglerg committed
197
198
199
            self.grid[cell_id[0]][cell_id[1]] = self.transitions.set_transitions(self.grid[cell_id[0]][cell_id[1]],
                                                                                 cell_id[2],
                                                                                 new_transitions)
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
        elif len(cell_id) == 2:
            self.grid[cell_id[0]][cell_id[1]] = new_transitions

    def get_transition(self, cell_id, transition_index):
        """
        Return the status of whether an agent in cell `cell_id' can perform a
        movement along transition `transition_index (e.g., the NESW direction
        of movement, for agents on a grid).

        Parameters
        ----------
        cell_id : tuple
            The cell_id indices a cell as (column, row, orientation),
            where orientation is the direction an agent is facing within a cell.
        transition_index : int
            Index of the transition to probe, as index in the tuple returned by
            get_transitions(). e.g., the NESW direction of movement, for agents
            on a grid.

        Returns
        -------
u214892's avatar
u214892 committed
221
        int or float (depending on Transitions used in the )
222
223
224
225
            Validity of the requested transition (e.g.,
            0/1 allowed/not allowed, a probability in [0,1], etc...)

        """
u214892's avatar
u214892 committed
226
227
228

        assert len(cell_id) == 3, \
            'GridTransitionMap.get_transition() ERROR: cell_id tuple must have length 2 or 3.'
229
230
        return self.transitions.get_transition(self.grid[cell_id[0]][cell_id[1]], cell_id[2], transition_index)

231
    def set_transition(self, cell_id, transition_index, new_transition, remove_deadends=False):
232
233
234
235
236
237
238
239
240
241
242
243
244
245
        """
        Replaces the validity of transition to `transition_index' in cell
        `cell_id' with the new `new_transition'.


        Parameters
        ----------
        cell_id : tuple
            The cell_id indices a cell as (column, row, orientation),
            where orientation is the direction an agent is facing within a cell.
        transition_index : int
            Index of the transition to probe, as index in the tuple returned by
            get_transitions(). e.g., the NESW direction of movement, for agents
            on a grid.
u214892's avatar
u214892 committed
246
        new_transition : int or float (depending on Transitions used in the map.)
247
248
249
250
            Validity of the requested transition (e.g.,
            0/1 allowed/not allowed, a probability in [0,1], etc...)

        """
u214892's avatar
u214892 committed
251
252
        assert len(cell_id) == 3, \
            'GridTransitionMap.set_transition() ERROR: cell_id tuple must have length 3.'
253
254
255
256
257
258
        self.grid[cell_id[0]][cell_id[1]] = self.transitions.set_transition(
            self.grid[cell_id[0]][cell_id[1]],
            cell_id[2],
            transition_index,
            new_transition,
            remove_deadends)
259

260
261
262
263
264
265
266
267
268
269
270
271
    def save_transition_map(self, filename):
        """
        Save the transitions grid as `filename', in npy format.

        Parameters
        ----------
        filename : string
            Name of the file to which to save the transitions grid.

        """
        np.save(filename, self.grid)

u214892's avatar
u214892 committed
272
    def load_transition_map(self, package, resource):
273
274
275
276
277
278
279
        """
        Load the transitions grid from `filename' (npy format).
        The load function only updates the transitions grid, and possibly width and height, but the object has to be
        initialized with the correct `transitions' object anyway.

        Parameters
        ----------
280
281
282
283
        package : string
            Name of the package from which to load the transitions grid.
        resource : string
            Name of the file from which to load the transitions grid within the package.
284
285
286
        override_gridsize : bool
            If override_gridsize=True, the width and height of the GridTransitionMap object are replaced with the size
            of the map loaded from `filename'. If override_gridsize=False, the transitions grid is either cropped (if
spiglerg's avatar
spiglerg committed
287
288
            the grid size is larger than (height,width) ) or padded with zeros (if the grid size is smaller than
            (height,width) )
289
290

        """
291
292
        with path(package, resource) as file_in:
            new_grid = np.load(file_in)
293
294
295
296

        new_height = new_grid.shape[0]
        new_width = new_grid.shape[1]

u214892's avatar
u214892 committed
297
298
299
        self.width = new_width
        self.height = new_height
        self.grid = new_grid
300
301
302
303
304
305
306

    def cell_neighbours_valid(self, rcPos, check_this_cell=False):
        """
        Check validity of cell at rcPos = tuple(row, column)
        Checks that:
        - surrounding cells have inbound transitions for all the
            outbound transitions of this cell.
307

308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
        These are NOT checked - see transition.is_valid:
        - all transitions have the mirror transitions (N->E <=> W->S)
        - Reverse transitions (N -> S) only exist for a dead-end
        - a cell contains either no dead-ends or exactly one

        Returns: True (valid) or False (invalid)
        """
        cell_transition = self.grid[tuple(rcPos)]

        if check_this_cell:
            if not self.transitions.is_valid(cell_transition):
                return False

        gDir2dRC = self.transitions.gDir2dRC  # [[-1,0] = N, [0,1]=E, etc]
        grcPos = array(rcPos)
        grcMax = self.grid.shape

u214892's avatar
u214892 committed
325
        binTrans = self.get_full_transitions(*rcPos)  # 16bit integer - all trans in/out
326
327
        lnBinTrans = array([binTrans >> 8, binTrans & 0xff], dtype=np.uint8)  # 2 x uint8
        g2binTrans = np.unpackbits(lnBinTrans).reshape(4, 4)  # 4x4 x uint8 binary(0,1)
328
329
        gDirOut = g2binTrans.any(axis=0)  # outbound directions as boolean array (4)
        giDirOut = np.argwhere(gDirOut)[:, 0]  # valid outbound directions as array of int
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344

        # loop over available outbound directions (indices) for rcPos
        for iDirOut in giDirOut:
            gdRC = gDir2dRC[iDirOut]  # row,col increment
            gPos2 = grcPos + gdRC  # next cell in that direction

            # Check the adjacent cell is within bounds
            # if not, then this transition is invalid!
            if np.any(gPos2 < 0):
                return False
            if np.any(gPos2 >= grcMax):
                return False

            # Get the transitions out of gPos2, using iDirOut as the inbound direction
            # if there are no available transitions, ie (0,0,0,0), then rcPos is invalid
u214892's avatar
u214892 committed
345
            t4Trans2 = self.get_transitions(*gPos2, iDirOut)
346
347
348
349
350
351
352
            if any(t4Trans2):
                continue
            else:
                return False

        return True

u214892's avatar
u214892 committed
353
# TODO: improvement override __getitem__ and __setitem__ (cell contents, not transitions?)