File: _structure.py

package info (click to toggle)
python-expyriment 0.7.0%2Bgit34-g55a4e7e-3.2
  • links: PTS, VCS
  • area: main
  • in suites: stretch
  • size: 1,504 kB
  • ctags: 2,094
  • sloc: python: 12,766; makefile: 150
file content (1818 lines) | stat: -rw-r--r-- 55,076 bytes parent folder | download | duplicates (2)
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
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
"""
The design._structure module of expyriment.

This module contains a class implementing the experiment structure.

"""

__author__ = 'Florian Krause <florian@expyriment.org>, \
Oliver Lindemann <oliver@expyriment.org>'
__version__ = '0.7.0'
__revision__ = '55a4e7e'
__date__ = 'Wed Mar 26 14:33:37 2014 +0100'


import os
try:
    import locale
except ImportError:
    locale = None  # Does not exist on Android
import sys
import types
import codecs
import re
try:
    import csv
except ImportError:
    from expyriment.misc import _csv_reader_android as csv
from copy import deepcopy

import defaults
import expyriment
from expyriment.misc import constants
from expyriment.misc import Clock
from expyriment.misc import unicode2str, str2unicode
import randomize
import permute


class Experiment(object):
    """A class implementing a basic experiment."""

    def __init__(self, name=None, foreground_colour=None,
                 background_colour=None, text_font=None, text_size=None,
                 filename_suffix=None):
        """Create an experiment.

        Parameters
        ----------
        name : str, optional
            name of the experiment
        foreground_colour : (int, int, int), optional
        background_colour : (int,int,int), optional
        text_font : str, optional
        text_size : int, optional
        filename_suffix : str, optional
            additional suffix that will be added to the main event
            and data filename

        """
        if name is not None:
            self._name = name
        elif defaults.experiment_name is not None:
            self._name = defaults.experiment_name
        else:
            self._name = os.path.split(sys.argv[0])[1].replace(".py", "")
        if background_colour is not None:
            self._background_colour = background_colour
        else:
            self._background_colour = \
                defaults.experiment_background_colour
        if foreground_colour is not None:
            self._foreground_colour = foreground_colour
        else:
            self._foreground_colour = \
                defaults.experiment_foreground_colour
        if text_font is not None:
            self._text_font = text_font
        else:
            self._text_font = defaults.experiment_text_font
        if text_size is not None:
            self._text_size = text_size
        else:
            self._text_size = defaults.experiment_text_size
        if filename_suffix is not None:
            self._filename_suffix = filename_suffix
        else:
            self._filename_suffix = defaults.experiment_filename_suffix

        self.clear_bws_factors()
        self._data_variable_names = []
        self._experiment_info = []
        self._blocks = []
        self._block_id_counter = 0

        self._is_started = False
        self._is_initialized = False
        self._keyboard = None
        self._mouse = None
        self._clock = None
        self._subject = None
        self._screen = None
        self._data = None
        self._events = None
        self._log_level = 0  # will be set from initialize
        self._wait_callback_function = None

    @property
    def name(self):
        """Getter for name."""

        return self._name

    @property
    def blocks(self):
        """Getter for blocks."""

        return self._blocks

    @property
    def background_colour(self):
        """Getter for background_colour."""

        return self._background_colour

    @property
    def foreground_colour(self):
        """Getter for foreground_colour."""

        return self._foreground_colour

    @property
    def text_font(self):
        """Getter for text_font."""

        return self._text_font

    @property
    def text_size(self):
        """Getter for text_size."""

        return self._text_size

    @property
    def filename_suffix(self):
        """Getter for filename suffix."""

        return self._filename_suffix

    @property
    def screen(self):
        """Getter for global screen."""

        return self._screen

    @property
    def data(self):
        """Getter for main data file."""

        return self._data

    @property
    def events(self):
        """Getter for main event files."""

        return self._events

    @property
    def log_level(self):
        """Getter for event logging. """

        return self._log_level

    @property
    def clock(self):
        """Getter for global clock."""

        return self._clock

    @property
    def keyboard(self):
        """Getter for global keyboard."""

        return self._keyboard

    @property
    def mouse(self):
        """Getter for global keyboard."""

        return self._mouse

    @property
    def subject(self):
        """Getter for global subject id."""

        return self._subject

    @property
    def is_started(self):
        """Getter for is_started."""

        return self._is_started

    @property
    def is_initialized(self):
        """Getter for is_initialized."""

        return self._is_initialized

    def __str__(self):
        tmp_str = "Experiment: {0}\n".format(unicode2str(self.name))
        if len(self.bws_factor_names) <= 0:
            tmp_str = tmp_str + "no between subject factors\n"
        else:
            tmp_str = tmp_str + "between subject factors (permutation type: "
            if self.bws_factor_randomized:
                tmp_str = tmp_str + "random)\n"
            else:
                tmp_str = tmp_str + "latin square)\n"
            for f in self.bws_factor_names:
                _bws_factor = \
                    [unicode2str(x) if isinstance(x, unicode) else
                     repr(x) for x in self._bws_factors[f]]
                tmp_str = tmp_str + "    {0} = [{1}]\n".format(
                    unicode2str(f), ", ".join(_bws_factor))
        for block in self.blocks:
            tmp_str = tmp_str + "{0}\n".format(unicode2str(block.summary))
        return tmp_str

    @property
    def data_variable_names(self):
        """Getter for data_variable_names."""

        return self._data_variable_names

    @data_variable_names.setter
    def data_variable_names(self, value):
        """Setter for data_variable_names."""

        self.clear_data_variable_names()
        self.add_data_variable_names(value)

    def clear_data_variable_names(self):
        """Remove all data variable names from design."""

        self._data_variable_names = []
        if self.data is not None:
            self.data.clear_variable_names()

    def add_data_variable_names(self, variable_names):
        """Add data variable names to the design.

        Parameters
        ----------
        variables : str or lst of str
            variable names

        """
        if variable_names is None:
            return
        if type(variable_names) is not list:
            variable_names = [variable_names]
        self._data_variable_names.extend(variable_names)
        if self.data is not None:
            self.data.add_variable_names(variable_names)

    @property
    def experiment_info(self):  # experiment_info can not be cleared!
        """Getter for experiment_info."""

        return self._experiment_info

    def add_experiment_info(self, text):
        """Add experiment information to the design.

        Parameters
        ----------
        text : string or list of str
            text lines to be added as experiment information

        """

        if text is None:
            return
        if type(text) is not list:
            text = [text]
        self._experiment_info.extend(text)
        if self.data is not None:
            self.data.add_experiment_info(text)

    @property
    def bws_factor_randomized(self):
        """Getter for bws_factor_randomized.

        Notes
        -----
        Is between subject factor randomized? (True/False).

        If True conditions will be assigned randomized
        otherwise (default) conditions will be systematically permuted across
        subjects.

        """

        return self._bws_factor_randomized

    @bws_factor_randomized.setter
    def bws_factor_randomized(self, value):
        """Setter for bws_factor_randomized."""

        self._bws_factor_randomized = value

    def add_bws_factor(self, factor_name, conditions):
        """Add a between subject factor.

        The defined between subject factor conditions will be permuted across
        the subjects. Factors that are added first are treated as
        hierarchically higher factors while permutation.

        Parameters
        ----------
        factor_name : str
            the name of the between subject factor
        conditions : list
            possible conditions of the between subject factor

        """

        if type(conditions) is not list:
            conditions = [conditions]
        self._bws_factors[factor_name] = conditions
        self._bws_factors_names.append(factor_name)
        self._randomized_condition_for_subject[factor_name] = {}

    def get_bws_factor(self, factor_name):
        """Return all conditions of this between subject factor."""

        try:
            cond = self._bws_factors[factor_name]
        except:
            return None
        return cond

    def get_permuted_bws_factor_condition(self, factor_name, subject_id=None):
        """Get the between subject factor condition for a subject.

        The condition for the current subject will be returned, if expyriment
        is running and the function is called without a subject_id.
        If the function is called with a subject_id, the condition for this
        particular subject will be returned.

        Parameters
        ----------
        factor_name : str
        subject_id : str, optional
            (default=None)

        Returns
        -------
        cond : str
            condition for the current subject

        """

        if subject_id is None:
            if self.subject is None:  # No current subject id defined
                return None
            else:  # Use current subject
                return self.get_permuted_bws_factor_condition(
                    factor_name, subject_id=self.subject)
        else:
            conditions = self.get_bws_factor(factor_name)
            if conditions is None:
                return None  # Factor not defined
            else:
                cond_idx = 0
                if self.bws_factor_randomized:
                    try:
                        cond_idx = self._randomized_condition_for_subject[
                            factor_name][subject_id]
                    except:  # If not yet randomized for this subject, do it
                        cond_idx = randomize.rand_int(
                            0, len(self._bws_factors[factor_name]) - 1)
                        self._randomized_condition_for_subject[
                            factor_name][subject_id] = cond_idx

                else:  # Permutation
                    # (n_cond_lower_fac) total number of conditions for all
                    # hierarchically lower factors
                    n_cond_lower_fac = self.n_bws_factor_conditions
                    for fac in self.bws_factor_names:
                        n_cond_lower_fac -= len(self.get_bws_factor(fac))
                        if fac is factor_name:
                            break
                    if n_cond_lower_fac <= 0:
                        n_cond_lower_fac = 1
                    cond_idx = ((subject_id - 1) / n_cond_lower_fac) % \
                        len(self.get_bws_factor(fac))
                return self._bws_factors[factor_name][cond_idx]

    def clear_bws_factors(self):
        """Remove all between subject factors from design."""

        self._bws_factors = {}

        # Can't use dict_keys, because dicts don't keep the order
        self._bws_factors_names = []

        self._randomized_condition_for_subject = {}
        self.bws_factor_randomized = False

    @property
    def bws_factor_names(self):
        """Getter for factors keys."""
        return self._bws_factors_names

    @property
    def n_bws_factor_conditions(self):
        """Getter for n_bws_factor_conditions.

        Total number of conditions in all bws_factors.

        """

        n = 0
        for fn in self.bws_factor_names:
            n += len(self.get_bws_factor(fn))
        return n

    def set_log_level(self, loglevel):
        """Set the log level of the current experiment

        Parameters
        ----------
        loglevel : int
            The log level (0, 1, 2) of the experiment.

        Notes
        -----
        There are three event logging levels:

        - O no event logging
        - 1 normal event logging (logging of all input & output events)
        - 2 intensive logging. Logs much more. Please use this only for
          debugging proposes.

        In most cases, it should be avoided to switch of logging (loglevel=0).
        It log files become to big due to certain repetitive events, it is
        suggested to switch of the logging of individual stimuli or IO event.
        (see the method `.set_logging()` of this objects)

        The logging of events can be also changed before initialize via the
        default value `expyriment.control.defaults.event_logging`.

        """

        self._log_level = int(loglevel)

    def add_block(self, block, copies=1):
        """Add a block to the experiment.

        Parameters
        ----------
        block : design.Block
            block to add
        copies : int, optional
            number of copies to add (default = 1)

        """

        for _x in range(0, copies):
            self._blocks.append(block.copy())
            self._blocks[-1]._id = self._block_id_counter
            self._block_id_counter += 1

        expyriment._active_exp._event_file_log(
            "Experiment,block added,{0},{1}".format(
                unicode2str(self.name), self._blocks[-1]._id), 2)

    def remove_block(self, position):
        """Remove block from experiment.

        If no position is given, the last one is removed.

        Parameters
        ----------
        position : int
            position of the block to be removed

        """

        block = self._blocks.pop(position)

        expyriment._active_exp._event_file_log(
            "Experiment,block removed,{0},{1}".format(unicode2str(self.name),
                                                      block.id), 2)

    def clear_blocks(self):
        """Remove all blocks from experiment."""

        self._blocks = []
        self._block_id_counter = 0

        expyriment._active_exp._event_file_log("Experiment,blocks cleared", 2)

    def order_blocks(self, order):
        """Order the blocks.

        Parameters
        ----------
        order : list
            list with the new order of positions

        """

        if not len(order) == len(self._blocks):
            raise ValueError("Given order has wrong number of items!")
        blocks_new = []
        for position in order:
            blocks_new.append(self._blocks[position])
        self._blocks = blocks_new

    @property
    def n_blocks(self):
        """Getter for n_blocks.

        Number of blocks.

        """

        return len(self._blocks)

    def swap_blocks(self, position1, position2):
        """Swap two blocks.

        Parameters
        ----------
        position1 : int
            position of first block
        position2 : int
            position of second block

        """

        if position1 < len(self._blocks) and position2 < len(self._blocks):
            self._blocks[position1], self._blocks[position2] = \
                self._blocks[position2], self._blocks[position1]
            return True
        else:
            return False

    def shuffle_blocks(self):
        """Shuffle all blocks."""

        randomize.shuffle_list(self._blocks)

    def permute_blocks(self, permutation_type, factor_names=None,
                       subject_id=None):
        """Permute the blocks.

        Parameters
        ----------
        permutation_type : int (permutation type)
            type of block order permutation (permutation type)
            Permutation types defined in misc.constants:
            P_BALANCED_LATIN_SQUARE, P_CYCLED_LATIN_SQUARE, and P_RANDOM
        factor_names : list (of strings), optional
            list of the factor names to be considered while permutation.
            If factor_names are not defined (None) all factors will be used.
        subject_id : int, optional
            subject number for this permutation
            If subject_id is defined or none (default) and experiment has
            been started, the current subject number will be used

        """

        if subject_id is None:
            if self.subject is None:
                raise RuntimeError("If Expyriment is not started, \
a subject number needs to be defined for the permutation.")
            else:
                subject_id = self.subject

        if not permute.is_permutation_type(permutation_type):
                raise AttributeError("{0} is a unknown permutation \
type".format(permutation_type))
        if factor_names is None:
            factor_names = self.block_list_factor_names

        # Get the condition combinations for the specified factors:
        all_factor_combi = []
        for b in self.blocks:
            combi = []
            for f in factor_names:
                combi.append([f, b.get_factor(f)])
            new = True
            for c in all_factor_combi:
                if c == combi:
                    new = False
            if new:  # Add only a new combination
                all_factor_combi.append(combi)

        # Get the permutation
        if permutation_type == constants.P_BALANCED_LATIN_SQUARE:
            permutation = permute.balanced_latin_square(all_factor_combi)
            idx = (subject_id - 1) % len(permutation)
            permutation = permutation[idx]
        elif permutation_type == constants.P_CYCLED_LATIN_SQUARE:
            permutation = permute.cycled_latin_square(all_factor_combi)
            idx = (subject_id - 1) % len(permutation)
            permutation = permutation[idx]
        else:
            randomize.shuffle_list(all_factor_combi)
            permutation = all_factor_combi

        tmp = self._blocks
        self._blocks = []
        for search_combi in permutation:
            # Search tmp block for this comb
            # And add all fitting blocks  (multiple addings possible)
            for b in tmp:
                combi = []
                for f in factor_names:
                    combi.append([f, b.get_factor(f)])
                if combi == search_combi:
                    self._blocks.append(b)

    def sort_blocks(self):
        """Sort the blocks according to their indices from low to high."""

        blocks_new = []
        id_list = [x.id for x in self._blocks]
        id_list.sort()
        for id in id_list:
            position = [i for i, x in enumerate(self._blocks)
                        if x.id == id][0]
            blocks_new.append(self._blocks[position])
        self._blocks = blocks_new

    def find_block(self, id):
        """Find the position of a block, given the id.

        Parameters
        ----------
        id : int
            block id to look for

        Returns
        -------
        pos: int
         positions as a list or None if not in block list.

        """

        positions = [i for i, x in enumerate(self._blocks) if x.id == id]
        if positions:
            return positions

    @property
    def trial_factor_names(self):
        """Getter for trial_factor_nanes.

        Get all factor names defined in the trial lists of all blocks.

        """

        factors = []
        for bl in self.blocks:
            factors.extend(bl.trial_factor_names)
        return list(set(factors))

    @property
    def block_list_factor_names(self):
        """Getter for block_list_factor_names.

        Get all factor names defined in all blocks.

        """

        factors = []
        for bl in self.blocks:
            factors.extend(bl.factor_names)
        return list(set(factors))

    @property
    def design_as_text(self):
        """Getter for desing_as_text.

        Trial list as csv table.

        """

        rtn = u"#exp: {0}\n".format(self.name)
        if len(self.experiment_info) > 0:
            for txt in self.experiment_info:
                rtn += u"#xpi: {0}\n".format(txt)
        if len(self.bws_factor_names) > 0:
            for factor_name in self.bws_factor_names:
                rtn += u"#bws: {0}=".format(factor_name)
                for txt in self.get_bws_factor(factor_name):
                    rtn += u"{0},".format(txt)
                rtn = rtn[:-1] + "\n"  # delete last comma
            rtn += u"#bws-rand: {0}\n".format(int(self.bws_factor_randomized))
        if len(self.data_variable_names) > 0:
            rtn += "#dvn: "
            for txt in self.data_variable_names:
                rtn += u"{0},".format(txt)
            rtn = rtn[:-1] + "\n"

        rtn += "block_cnt,block_id"
        bl_factors = self.block_list_factor_names
        factors = self.trial_factor_names
        for f in bl_factors:
            rtn += u",block_{0}".format(f)
        rtn += ",trial_cnt,trial_id"
        for f in factors:
            rtn += u",{0}".format(f)

        for bl_cnt, bl in enumerate(self.blocks):
            for tr_cnt, tr in enumerate(bl.trials):
                rtn += u"\n{0},{1}".format(bl_cnt, bl.id)
                for f in bl_factors:
                    rtn += u",{0}".format(bl.get_factor(f))
                rtn += u",{0},{1}".format(tr_cnt, tr.id)
                for f in factors:
                    rtn += u",{0}".format(tr.get_factor(f))

        return rtn

    def save_design(self, filename):
        """Save the design as list of trials to a csv file.

        The function considers only the defined trial factors and not the
        added stimuli.

        Notes
        -----
        The current version of this function does not handle between_subject
        factors and data_variables.

        Parameters
        ----------
        filename : str
            name (fullpath) of the csv file (str)

        """

        with open(filename, 'w') as f:
            try:
                locale_enc = locale.getdefaultlocale()[1]
            except:
                locale_enc = "UTF-8"
            header = "# -*- coding: {0} -*-\n".format(
                locale_enc)
            f.write(header + unicode2str(self.design_as_text))

    def load_design(self, filename, encoding=None):
        """Load the design from a csv file containing list of trials.

        The function considers only the defined trial factors and not the
        added stimuli. The existing design will be deleted.

        Notes
        -----
        The current version of this function does not handle between_subject
        factors and data_variables.

        Parameters
        ----------
        filename : str
            name (fullpath) of the csv file (str)

        encoding : str, optional
            the encoding to be used when reading from the file

        """

        delimiter = ","
        self.clear_blocks()
        block_factors = {}
        trial_factors = {}
        if encoding is None:
            with open(filename, 'r') as fl:
                first_line = fl.readline()
                encoding = re.findall("coding[:=]\s*([-\w.]+)", first_line)
                if encoding == []:
                    second_line = fl.readline()
                    encoding = re.findall("coding[:=]\s*([-\w.]+)",
                                          second_line)
                    if encoding == []:
                        encoding = [None]
        else:
            encoding = [encoding]
        with codecs.open(filename, 'rb', encoding[0], errors='replace') as fl:
            for ln in fl:
                ln = str2unicode(ln)
                if ln[0] == "#":
                    if ln.startswith("#exp:"):
                        self._name = ln[6:].strip()
                    elif ln.startswith("#xpi:"):
                        self.add_experiment_info(ln[6:].strip())
                    elif ln.startswith("#dvn:"):
                        for tmp in ln[6:].split(","):
                            self.add_data_variable_names(tmp.strip())
                    elif ln.startswith("#bws-rand:"):
                        self.bws_factor_randomized = (ln[11] == "1")
                    elif ln.startswith("#bws:"):
                        tmp = ln[6:].split("=")
                        print tmp[1].strip().split(",")
                        self.add_bws_factor(tmp[0], tmp[1].strip().split(","))

                else:  # data line
                    if len(block_factors) < 1:
                        # read first no-comment line --> varnames
                        for col, var in enumerate(ln.split(delimiter)):
                            var = var.strip()
                            if var.startswith("block_"):
                                var = var.replace("block_", "")
                                block_factors[col] = var
                            elif var.startswith("trial_"):
                                var = var.replace("trial_", "")
                                trial_factors[col] = var
                            else:
                                trial_factors[col] = var

                        if not("cnt" in block_factors.values() and
                               "id" in block_factors.values() and
                               "cnt" in trial_factors.values() and
                               "id" in trial_factors.values()):
                            message = "Can't read design file. " + \
                                "The file '{0}' ".format(
                                    unicode2str(filename)) + \
                                "does not contain an Expyriment trial list."
                            raise IOError(message)
                    else:
                        block_cnt = None
                        trial_cnt = None
                        # read data
                        for col, val in enumerate(ln.split(delimiter)):
                            val = val.strip()
                            # try to convert to number
                            if val.find(".") >= 0:
                                try:
                                    val = float(val)
                                except:
                                    pass
                            else:
                                try:
                                    val = int(val)
                                except:
                                    pass

                            # set value to block or trial
                            if col in block_factors:
                                if block_factors[col] == "cnt":
                                    block_cnt = val
                                    while len(self.blocks) < block_cnt + 1:
                                        self.add_block(Block())
                                elif block_factors[col] == "id":
                                    self.blocks[block_cnt]._id = val
                                else:
                                    self.blocks[block_cnt].set_factor(
                                        block_factors[col], val)

                            if col in trial_factors:
                                if trial_factors[col] == "cnt":
                                    trial_cnt = val
                                    while len(self.blocks[block_cnt].trials)\
                                            < trial_cnt + 1:
                                        self.blocks[block_cnt].add_trial(
                                            Trial())
                                elif trial_factors[col] == "id":
                                    self.blocks[block_cnt].trials[trial_cnt].\
                                        _id = val
                                else:
                                    self.blocks[block_cnt].trials[trial_cnt].\
                                        set_factor(trial_factors[col], val)

    def _event_file_log(self, log_text, log_level=1):
        # log_level 1 = default, 2 = extensive, 0 or False = off
        """ Helper function to log event in the global experiment event file"""
        if self.is_initialized and\
                self._log_level > 0 and\
                self._log_level >= log_level and \
                self.events is not None:
            self.events.log(log_text)

    def _event_file_warn(self, warning, log_level=1):
        """ Helper function to log event in the global experiment event file"""
        if self.is_initialized and\
                self._log_level > 0 and\
                self._log_level >= log_level and \
                self.events is not None:
            self.events.log(warning)

    def log_design_to_event_file(self, additional_comment=""):
        """Log the design (as comment) to the current main event file.

        If no experiment is initialized or no event file exists the function
        will not do anything. This function will be automatically called after
        an experiment has been started.

        Notes
        -----
        See also save_design().

        Parameters
        ----------
        additional_comment : str, optional
            additional comment that will be logged

        """

        if self.is_initialized and self.events is not None:
            self.events.log("design,log,{0}".format(
                unicode2str(additional_comment)))
            for ln in self.design_as_text.splitlines():
                self.events.write_comment(
                    "design: {0}".format(unicode2str(ln)).replace(
                        ":#", "-"))
            self.events.log("design,logged,{0}".format(
                unicode2str(additional_comment)))

    def register_wait_callback_function(self, function):
        """Register a wait callback function.

        Notes
        -----
        CAUTION! If wait callback function takes longer than 1 ms to process,
        Expyriment timing will be affected!

        The registered wait callback function will be repetitively executed in
        all Expyriment wait and event loops that wait for an external input.
        That is, they are executed by the following functions (at least once!):

        - control.wait_end_audiosystem
        - misc.clock.wait
        - misc.clock.wait_seconds
        - misc.clock.wait_minutes
        - io.keyboard.wait
        - io.keyboard.wait_char
        - io.buttonbox.wait
        - io.gamepad.wait_press
        - io.triggerinput.wait
        - io.mouse.wait_press
        - io.serialport.read_line
        - io.textinput.get
        - io.TouchScreenButtonBox.wait
        - io.extras.CedrusResponseDevice.wait
        - stimulus.video.wait_frame
        - stimulus.video.wait_end

        Parameters
        ----------
        function : function
            wait function (function)

        """

        if type(function) == types.FunctionType:
            self._wait_callback_function = function
        else:
            raise AttributeError("register_wait_callback_function requires " +
                                 "a function as parameter")

    def unregister_wait_callback_function(self):
        """Unregister wait function."""

        self._wait_callback_function = None

    def _execute_wait_callback(self):
        """Execute wait function.

        Returns True if wait function is defined and executed.

        """

        if self._wait_callback_function is not None:
            self._wait_callback_function()
            return True
        else:
            return False


class Block(object):
    """A class implementing an experimental block."""

    _trial_cnt_variable_name = "trial_cnt"  # variable names for csv in/output
    _trial_id_variable_name = "trial_id"

    def __init__(self, name=None):
        """Create a block.

        Parameters
        ----------
        name : str, optional
            name of the block

        """

        if name is not None:
            self._name = name
        else:
            self._name = defaults.block_name

        self._factors = {}
        self._trials = []
        self._trial_id_counter = 0
        self._id = None

    @property
    def name(self):
        """Getter for name."""

        return self._name

    @property
    def id(self):
        """Getter for id."""

        return self._id

    @property
    def trials(self):
        """Getter for trials."""

        return self._trials

    def __str__(self):
        return unicode2str(self._get_summary(True))

    @property
    def summary(self):
        """Getter for summary."""

        return self._get_summary(False)

    def _get_summary(self, include_trial_IDs):
        """Return a summary of the trials as string."""

        if self.name is None:
            name = ""
        else:
            name = self.name
        rtn = u"""Block {0}: {1}
    block factors: {2}
    n trials: {3}""".format(self.id, name,
                            self.factors_as_text,
                            len(self.trials))

        if include_trial_IDs:
            rtn = rtn + u"""
    trial IDs = {0}""".format([t.id for t in self.trials])
        rtn = rtn + u"""
    trial factors: """
        for f in self.trial_factor_names:
            val = []
            for tf in self.get_trial_factor_values(f):
                if tf not in val:
                    val.append(tf)
            val.sort()
            val = [repr(x) if type(x) not in [unicode, str]
                   else x for x in val]
            rtn = rtn + u"{0} = [{1}]\n                   ".format(
                f, ", ".join(val))

        return rtn

    @property
    def factors_as_text(self):
        """Getter for factors_as_text.

        Return all factor names and values as string line.

        """

        all_factors = ""
        for f in self.factor_names:
            all_factors = all_factors + \
                u"{0} = {1}\n                   ".format(
                    f, self.get_factor(f))
        all_factors = all_factors.rstrip()
        if len(all_factors) >= 1 and all_factors[-1] == ",":
            all_factors = all_factors[:-1]
        return all_factors

    def set_factor(self, name, value):
        """Set a factor for the block.

        Parameters
        ----------
        name : str
            factor name
        value : str or numeric
            factor value

        """

        if type(value) in [types.StringType, types.UnicodeType, types.IntType,
                           types.FloatType]:
            self._factors[name] = value
        else:
            message = "Factor values or factor conditions must to be a " + \
                "String or a Number (i.e. float or integer).\n " + \
                "{0} is not allowed.".format(type(value))
            raise TypeError(message)

    def get_factor(self, name):
        """Get a factor of the block.

        Parameters
        ----------
        name : str
            factor name (str)

        """

        try:
            rtn = self._factors[name]
        except:
            rtn = None
        return rtn

    @property
    def factor_dict(self):
        """The dictionary with all factors of the block."""

        return self._factors

    def clear_factors(self):
        """Clear all factors."""

        self._factors = {}

    @property
    def factor_names(self):
        """Getter for factor_names.

        Factor keys.

        """

        return self._factors.keys()

    def get_random_trial(self):
        """Returns a randomly selected trial.

        Notes
        -----
        This function is useful for compiling training blocks.

        Returns
        -------
        rnd : design.Trial
            random Expyriment trial
        """

        rnd = randomize.rand_int(0, len(self._trials) - 1)
        return self._trials[rnd]

    def add_trial(self, trial, copies=1, random_position=False):
        """Add trial to the block.

        Parameters
        ----------
        trial : design.Trial
            trial to add
        copies : int, optional
            number of copies to add (default = 1)
        random_position : bool, optional
            True  = insert trials at random position,
            False = append trials at the end (default=False)

        """

        for _x in range(0, copies):
            if random_position:
                pos = randomize.rand_int(0, len(self._trials))
                self._trials.insert(pos, trial.copy())
            else:
                self._trials.append(trial.copy())
            self._trials[-1]._id = self._trial_id_counter
            self._trial_id_counter += 1

        log_txt = "Block,trial added,{0}, {1}".format(unicode2str(self.name),
                                                      self._trials[-1]._id)
        if random_position:
            log_txt = log_txt + ", random position"
        expyriment._active_exp._event_file_log(log_txt, 2)

    def remove_trial(self, position):
        """Remove a trial.

        Parameters
        ----------
        position : int
            position of the trial

        """

        trial = self._trials.pop(position)

        expyriment._active_exp._event_file_log(
            "Block,trial removed,{0},{1}".format(self.id, trial.id), 2)

    def clear_trials(self):
        """Clear all trials."""

        self._trials = []
        self._trial_id_counter = 0

        expyriment._active_exp._event_file_log("Block,trials cleared", 2)

    @property
    def n_trials(self):
        """Getter for n_trials.

        Number of trials.

        """

        return len(self._trials)

    @property
    def trial_factor_names(self):
        """Getter for trial_factor_names.

        Get all factor names defined in trial list.

        """

        if len(self.trials) < 1:
            return []
        rtn = self.trials[0].factor_names
        for tr in self.trials:
            for new_fac in tr.factor_names:
                is_new = True
                for old_fac in rtn:
                    if old_fac == new_fac:
                        is_new = False
                        break
                if is_new:
                    rtn.append(new_fac)
        return rtn

    def get_trial_factor_values(self, name):
        """Return a list of the values of a certain factor for all trials.

        Parameters
        ----------
        name : str
            name of the factor

        """

        rtn = []
        for trial in self.trials:
            rtn.append(trial.get_factor(name))
        return rtn

    @property
    def design_as_text(self):
        """Getter for design_as_text.

        List of trial factors as csv table.

        The list considers only the defined trial factors and not the
        added stimuli.

        """

        rtn = "{0},{1}".format(self._trial_cnt_variable_name,
                               self._trial_id_variable_name)
        factors = self.trial_factor_names
        for f in factors:
            rtn = rtn + ",{0}".format(unicode2str(f))
        for cnt, tr in enumerate(self.trials):
            rtn = rtn + "\n{0},{1}".format(cnt, tr.id)
            for f in factors:
                rtn = rtn + ",{0}".format(unicode2str(tr.get_factor(f)))
        return rtn

    def save_design(self, filename):
        """Save the list of trials to a csv file.

        The function considers only the defined trial factors and not the
        added stimuli.

        Parameters
        filename  -- name (fullpath) of the csv file

        """

        with open(filename, 'w') as f:
            try:
                locale_enc = locale.getdefaultlocale()[1]
            except:
                locale_enc = "UTF-8"
            header = "# -*- coding: {0} -*-\n".format(
                locale_enc)
            f.write(header + unicode2str(self.design_as_text))

    def read_design(self, filename):
        """Reads a list of trials from a csv file and clears the old block
        design.

        The function considers only the trial factors and not the added
        stimuli. All factors will be read in as text strings and not casted to
        numericals. Please do this manually if required.

        Parameters
        ----------
        filename : str
            name (fullpath) of the csv file (str)

        """

        tmp = Block()
        tmp.add_trials_from_csv_file(filename)
        fac_names = tmp.trial_factor_names

        self.clear_factors()
        self.clear_trials()

        for tr in tmp.trials:
            new = Trial()
            for fac in fac_names:
                if fac == self._trial_cnt_variable_name:
                    pass
                elif fac == self._trial_id_variable_name:
                    new._id = int(tr.get_factor(fac))
                else:
                    new.set_factor(fac, tr.get_factor(fac))
            self.add_trial(new)

    def add_trials_from_csv_file(self, filename, encoding=None):
        """Read a list of trials from csv-file and append the new trials to the
        block. Trials are defined as combinations of trial factors.

        **csv-file specifications**

            The first row of the csv-file specifies the factor names. Each
            following row describes one trial. Each row must have the same
            amount of columns.

        Notes
        ------
        All factors will be read in as text strings and not casted to
        numericals. Please do this manually if required.

        Parameters
        ----------
        filename : str
            name (fullpath) of the csv file (str)

        encoding : str, optional
            the encoding to be used when reading from the file

        """

        factor_names = []
        if encoding is None:
            with open(filename, 'r') as fl:
                first_line = fl.readline()
                encoding = re.findall("coding[:=]\s*([-\w.]+)", first_line)
                if encoding == []:
                    second_line = fl.readline()
                    encoding = re.findall("coding[:=]\s*([-\w.]+)",
                                          second_line)
                    if encoding == []:
                        encoding = [None]
        else:
            encoding = [encoding]
        with codecs.open(filename, "rb", encoding[0], errors='replace') as f:
            reader = csv.reader(f)
            for r_cnt, row in enumerate(reader):
                if r_cnt == 0:
                    factor_names = deepcopy(str2unicode(row))
                else:
                    trial = Trial()
                    for c_cnt in range(0, len(row)):
                        trial.set_factor(str2unicode(factor_names[c_cnt]),
                                         str2unicode(row[c_cnt]))
                    self.add_trial(trial)

    def order_trials(self, order):
        """Order the trials.

        Parameters
        ----------
        order : list
            list with the new order of positions

        """

        if not len(order) == len(self._trials):
            raise ValueError("Given order has wrong number of items!")
        trials_new = []
        for position in order:
            trials_new.append(self._trials[position])
        self._trials = trials_new

    def swap_trials(self, position1, position2):
        """Swap two trials.

        Parameters
        ----------
        position1 : int
            position of first trial
        position2 : int
            position of second trial

        """

        if position1 < len(self._trials) and position2 < len(self._trials):
            self._trials[position1], self._trials[position2] = \
                self._trials[position2], self._trials[position1]
            return True
        else:
            return False

    @property
    def max_trial_repetitions(self):
        """Getter for max_trial_repetitions.

        Returns the maximum number of immediate trial repetitions.

        """

        tmp = []
        for t in self._trials:
            tmp.append(t.factors_as_text)

        max_reps = 0
        cnt = 0
        for x in range(1, len(tmp) - 1):
            if tmp[x - 1] == tmp[x]:
                cnt += 1
                if cnt > max_reps:
                    max_reps = cnt
            else:
                cnt = 0
        return max_reps

    def shuffle_trials(self, method=0, max_repetitions=None):
        """Shuffle all trials.

        The function returns False if no randomization could be found that
        fulfills the max immediate trial repetition criterion. The different
        type of trials are only defined by the factors. Shuffle does not
        take into account the added stimuli.

        The following randomization methods are defined:

                0 = total randomization of trial order (default),

                1 = randomization within small miniblocks. Each miniblock
                contains one trial of each type (only defined by factors!).
                In other words, copies of one trial type are always in
                different miniblocks.

        Parameters
        ----------
        method : int, optional
            method of trial randomization (default=0)
        max_repetitions : int, optional
            maximum number of allowed immediate repetitions.
            If None the repetition criterion will be ignored

        Returns
        -------
        succeeded : bool

        """

        start = Clock._cpu_time()
        cnt = 0
        while True:
            cnt += 1
            self._shuffle_trials(method)
            if max_repetitions is None or \
                    (self.max_trial_repetitions <= max_repetitions):
                return True
            else:
                if (Clock._cpu_time() - start) * 1000 >= \
                        defaults.max_shuffle_time:
                    print "Warning: Could not find an appropriate trial " + \
                          "randomization ({0} attempts)!".format(cnt)
                    return False

    def _shuffle_trials(self, method):
        """actual implementation of the trial shuffling"""
        if method == 1:  # shuffling blockwise
            cp = self.copy()
            randomize.shuffle_list(cp._trials)
            self._trials = []
            types_occured = []
            cnt = 0
            while len(cp._trials) > 0:
                tr = cp._trials[cnt]
                new = True
                tr_type = tr.factors_as_text
                for occ in types_occured:
                    if tr_type == occ:
                        new = False
                        break
                if new:
                    self._trials.append(tr)
                    cp._trials.pop(cnt)
                    types_occured.append(tr_type)
                    cnt = 0
                else:
                    cnt = cnt + 1
                    if cnt >= len(cp._trials):
                        types_occured = []
                        cnt = 0
        else:
            randomize.shuffle_list(self._trials)

    def sort_trials(self):
        """Sort the trials according to their indices from low to high."""

        trials_new = []
        id_list = [x.id for x in self._trials]
        id_list.sort()
        for _id in id_list:
            position = [i for i, x in enumerate(self._trials)
                        if x.id == _id][0]
            trials_new.append(self._trials[position])
        self._trials = trials_new

    def find_trial(self, id):
        """Find the positions of a trial.

        Parameters
        -----------
        id : int
            trial id to look for

        Returns
        -------
        pos : list
            positions as a list or None if not in trial list.

        """

        positions = [i for i, x in enumerate(self._trials) if x.id == id]
        if positions:
            return positions

    def copy(self):
        """Return a copy of the block."""

        owntrials = []
        triallist = []
        for trial in self._trials:
            owntrials.append(trial)
            triallist.append(trial.copy())
        self._trials = None
        rtn = deepcopy(self)
        self._trials = owntrials
        rtn._trials = triallist
        return rtn


class Trial(object):
    """A class implementing an experimental trial."""

    def __init__(self):
        """Create a Trial."""

        self._stimuli = []
        self._factors = {}
        self._id = None

    @property
    def stimuli(self):
        """Getter for stimuli."""

        return self._stimuli

    @property
    def id(self):
        """Getter for id."""

        return self._id

    def __str__(self):
        return """
        Trial:   {0}

        Stimuli: {1}
        """.format(str(self.id),
                   [stimulus.id for stimulus in self.stimuli])

    def set_factor(self, name, value):
        """Set a factor for the trial.

        Parameters
        ----------
        name : str
            factor name
        value : str or numeric
            factor value

        """

        if type(value) in [types.StringType, types.UnicodeType, types.IntType,
                           types.LongType, types.FloatType]:
            self._factors[name] = value
        else:
            message = "Factor values or factor conditions must to be a " + \
                "string or a numeric (i.e. float or integer).\n " + \
                "{0} is not allowed.".format(type(value))
            raise TypeError(message)

    def get_factor(self, name):
        """Get a factor of the trial.

        Parameters
        ----------
        name : str
            factor name

        Returns
        -------
        factor_val : str or numeric

        """

        try:
            rtn = self._factors[name]
        except:
            rtn = None
        return rtn

    @property
    def factor_dict(self):
        """The dictionary with all factors of the trial."""

        return self._factors

    def clear_factors(self):
        """Clear all factors."""

        self._factors = {}

    @property
    def factor_names(self):
        """Getter for factors names."""

        return self._factors.keys()

    @property
    def factors_as_text(self):
        """Return all factor names and values as csv string line"""
        all_factors = ""
        for f in self.factor_names:
            all_factors = all_factors + "{0}={1}, ".format(
                unicode2str(f), unicode2str(self.get_factor(f)))
        return all_factors

    def add_stimulus(self, stimulus):
        """Add a stimulus to the trial.

        Notes
        -----
        This will add references to stimuli, not copies!

        Parameters
        ----------
        stimulus : expyriment stimulus
            stimulus to add (expyriment.stimuli.* object)

        """

        self._stimuli.append(stimulus)

        expyriment._active_exp._event_file_log(
            "Trial,stimulus added,{0},{1}".format(self.id, stimulus.id), 2)

    def remove_stimulus(self, position):
        """Remove stimulus from trial.

        Parameters
        ----------
        position : int
            position of the stimulus

        """

        stimulus = self._stimuli.pop(position)

        expyriment._active_exp._event_file_log(
            "Trial,stimulus removed,{0},{1}".format(self.id, stimulus.id), 2)

    def order_stimuli(self, order):
        """Order the stimuli.

        Parameters
        ----------
        order : list
            list with the new order of positions

        """

        if not len(order) == len(self._stimuli):
            raise ValueError("Given order has wrong number of items!")
        stimuli_new = []
        for position in order:
            stimuli_new.append(self._stimuli[position])
        self._stimuli = stimuli_new

    def clear_stimuli(self):
        """Clear the stimuli."""

        self._stimuli = []
        expyriment._active_exp._event_file_log("Trial,stimuli cleared", 2)

    def swap_stimuli(self, position1, position2):
        """Swap two stimuli.

        Parameters
        ----------
        position1 : int
            position of first stimulus
        position2 : int
            position of second stimulus

        """

        if position1 < len(self._stimuli) and position2 < len(self._stimuli):
            self._stimuli[position1], self._stimuli[position2] = \
                self._stimuli[position2], self._stimuli[position1]
            return True
        else:
            return False

    def shuffle_stimuli(self):
        """Shuffle all stimuli."""

        randomize.shuffle_list(self.stimuli)

    def sort_stimuli(self):
        """Sort the stimuli according to their IDs from low to high."""

        stimuli_new = []
        id_list = [x.id for x in self._stimuli]
        id_list.sort()
        for _id in id_list:
            position = [i for i, x in enumerate(self._stimuli)
                        if x.id == _id][0]
            stimuli_new.append(self._stimuli[position])
        self._stimuli = stimuli_new

    def find_stimulus(self, id):
        """Find the positions of a stimulus.

        Parameters
        ----------
        id : int
            stimulus id to look for

        Returns
        -------
        pos : int
            positions as a list or None if not in stimuli list

        """

        positions = [i for i, x in enumerate(self._stimuli) if x.id == id]
        if positions:
            return positions

    def copy(self):
        """Return a copy of the trial."""

        stimlist = []
        for stim in self._stimuli:
            stimlist.append(stim)
        self._stimuli = None
        rtn = deepcopy(self)
        self._stimuli = rtn._stimuli = stimlist
        return rtn

    def preload_stimuli(self):
        """Preload all stimuli in trial.

        Returns
        -------
        time : int
            time it took to execute this method in ms

        """

        start = Clock._cpu_time()
        for stim in self._stimuli:
            stim.preload()
        return int((Clock._cpu_time() - start) * 1000)

    def unload_stimuli(self, keep_surface=False):
        """Unload all stimuli in trial.

        Parameters
        ----------
        keep_surface : bool, optional
            keep the surface after unloading (default = False)

        Returns
        -------
        time : int
            time it took to execute this method in ms

        """

        start = Clock._cpu_time()
        for stim in self._stimuli:
            stim.unload(keep_surface=keep_surface)
        return int((Clock._cpu_time() - start) * 1000)