Fixing the seed of the random generator?

[npinto]

Is there a way to fix the seed of the random generator, either as an option to gaussian(), uniform(), etc. (that could be access from e.g. root.random_seed) or a global option at the import level like import genson; genson.random_seed = 42 ?

[npinto]

How should we proceed to get a "global" random state ?

[davidcox]

The module-level option for a default random seed has some appeal. In this case, if there's a None or missing value for the random_seed kwarg in individual generators, they'd be obliged to check the module genson.default_random_seed value, if it is set.

I like less making it a special property on the genson_dict objects, since it would override the existing mechanisms -- that already provide this functionality, for the most part, if you want to use them that way. The only thing that I think is missing is for the generator objects to make sure that they check for a new value of the seed when they are reset.

[npinto]

@davidcox

I'm not sure I'm getting the right behavior from the following scripts

• genson file:

# plos09_l3_stride_one.gson                                                                                                                                                                                                                                           [[("lnorm",
   {"kwargs": {"inker_shape": choice([(3, 3), (5, 5), (7, 7), (9, 9)]),
               "outker_shape": this.inker_shape,
               "remove_mean": choice([false, true]),
               "stretch": choice([0.1, 1, 10]),
               "threshold": choice([0.1, 1, 10])}})],
 [("fbcorr",
   {"initialize": {"filter_shape": choice([(3, 3), (5, 5), (7, 7), (9, 9)]),
                   "generate": ("random:uniform", {"rseed": 42}),
                   "n_filters": choice([16, 32, 64])},
    "kwargs": {"max_out": choice([1, null]), "min_out": choice([null, 0])}}),
  ("lpool",
   {"kwargs": {"ker_shape": choice([(3, 3), (5, 5), (7, 7), (9, 9)]),
               "order": choice([1, 2, 10]),
               "stride": 1}}),
  ("lnorm",
   {"kwargs": {"inker_shape": choice([(3, 3), (5, 5), (7, 7), (9, 9)]),
               "outker_shape": this.inker_shape,
               "remove_mean": choice([false, true]),
               "stretch": choice([0.1, 1, 10]),
               "threshold": choice([0.1, 1, 10])}})],
 [("fbcorr",
   {"initialize": {"filter_shape": choice([(3, 3), (5, 5), (7, 7), (9, 9)]),
                   "generate": ("random:uniform", {"rseed": 42}),
                   "n_filters": choice([16, 32, 64, 128])},
    "kwargs": {"max_out": choice([1, null]), "min_out": choice([null, 0])}}),
  ("lpool",
   {"kwargs": {"ker_shape": choice([(3, 3), (5, 5), (7, 7), (9, 9)]),
               "order": choice([1, 2, 10]),
               "stride": 1}}),
  ("lnorm",
   {"kwargs": {"inker_shape": choice([(3, 3), (5, 5), (7, 7), (9, 9)]),
               "outker_shape": this.inker_shape,
               "remove_mean": choice([false, true]),
               "stretch": choice([0.1, 1, 10]),
               "threshold": choice([0.1, 1, 10])}})],
 [("fbcorr",
   {"initialize": {"filter_shape": choice([(3, 3), (5, 5), (7, 7), (9, 9)]),
                   "generate": ("random:uniform", {"rseed": 42}),
                   "n_filters": choice([16, 32, 64, 128, 256])},
    "kwargs": {"max_out": choice([1, null]), "min_out": choice([null, 0])}}),
  ("lpool",
   {"kwargs": {"ker_shape": choice([(3, 3), (5, 5), (7, 7), (9, 9)]),
               "order": choice([1, 2, 10]),
               "stride": 1}}),
  ("lnorm",
   {"kwargs": {"inker_shape": choice([(3, 3), (5, 5), (7, 7), (9, 9)]),
               "outker_shape": this.inker_shape,
               "remove_mean": choice([false, true]),
               "stretch": choice([0.1, 1, 10]),
               "threshold": choice([0.1, 1, 10])}})]]

• script to reproduce the bug:

# genson_random_bug.py
import genson

print genson.default_random_seed
genson.default_random_seed = 42

f = open('plos09_l3_stride_one.gson')
s = f.read()

from pprint import pprint
pprint(genson.loads(s).next())

• running it twice, I'm not getting the same output:

% python genson_random_bug.py                                                                                                                                                                                                                                             

registering: lognormal
registering: qlognormal
registering: uniform
registering: choice
registering: randint
None
[[('lnorm',
   OrderedDict([('kwargs', OrderedDict([('inker_shape', (5, 5)), ('outker_shape', (5, 5)), ('remove_mean', False), ('stretch', 0.1), ('threshold', 0.1)]))]))],
 [('fbcorr',
   OrderedDict([('initialize', OrderedDict([('filter_shape', (9, 9)), ('generate', ('random:uniform', OrderedDict([('rseed', 42)]))), ('n_filters', 32)])), ('kwargs', OrderedDict([('max_out', None), ('min_out', 0)]))])),
  ('lpool',
   OrderedDict([('kwargs', OrderedDict([('ker_shape', (3, 3)), ('order', 2), ('stride', 1)]))])),
  ('lnorm',
   OrderedDict([('kwargs', OrderedDict([('inker_shape', (3, 3)), ('outker_shape', (3, 3)), ('remove_mean', False), ('stretch', 1), ('threshold', 10)]))]))],
 [('fbcorr',
   OrderedDict([('initialize', OrderedDict([('filter_shape', (9, 9)), ('generate', ('random:uniform', OrderedDict([('rseed', 42)]))), ('n_filters', 16)])), ('kwargs', OrderedDict([('max_out', None), ('min_out', 0)]))])),
  ('lpool',
   OrderedDict([('kwargs', OrderedDict([('ker_shape', (3, 3)), ('order', 2), ('stride', 1)]))])),
  ('lnorm',
   OrderedDict([('kwargs', OrderedDict([('inker_shape', (9, 9)), ('outker_shape', (9, 9)), ('remove_mean', True), ('stretch', 10), ('threshold', 10)]))]))],
 [('fbcorr',
   OrderedDict([('initialize', OrderedDict([('filter_shape', (9, 9)), ('generate', ('random:uniform', OrderedDict([('rseed', 42)]))), ('n_filters', 128)])), ('kwargs', OrderedDict([('max_out', None), ('min_out', None)]))])),
  ('lpool',
   OrderedDict([('kwargs', OrderedDict([('ker_shape', (9, 9)), ('order', 10), ('stride', 1)]))])),
  ('lnorm',
   OrderedDict([('kwargs', OrderedDict([('inker_shape', (7, 7)), ('outker_shape', (7, 7)), ('remove_mean', True), ('stretch', 1), ('threshold', 0.1)]))]))]]


% python genson_random_bug.py                                                                                                                                                                                                                                             

registering: lognormal
registering: qlognormal
registering: uniform
registering: choice
registering: randint
None
[[('lnorm',
   OrderedDict([('kwargs', OrderedDict([('inker_shape', (3, 3)), ('outker_shape', (3, 3)), ('remove_mean', False), ('stretch', 1), ('threshold', 10)]))]))],
 [('fbcorr',
   OrderedDict([('initialize', OrderedDict([('filter_shape', (3, 3)), ('generate', ('random:uniform', OrderedDict([('rseed', 42)]))), ('n_filters', 16)])), ('kwargs', OrderedDict([('max_out', None), ('min_out', None)]))])),
  ('lpool',
   OrderedDict([('kwargs', OrderedDict([('ker_shape', (9, 9)), ('order', 2), ('stride', 1)]))])),
  ('lnorm',
   OrderedDict([('kwargs', OrderedDict([('inker_shape', (5, 5)), ('outker_shape', (5, 5)), ('remove_mean', True), ('stretch', 0.1), ('threshold', 1)]))]))],
 [('fbcorr',
   OrderedDict([('initialize', OrderedDict([('filter_shape', (3, 3)), ('generate', ('random:uniform', OrderedDict([('rseed', 42)]))), ('n_filters', 128)])), ('kwargs', OrderedDict([('max_out', 1), ('min_out', None)]))])),
  ('lpool',
   OrderedDict([('kwargs', OrderedDict([('ker_shape', (3, 3)), ('order', 1), ('stride', 1)]))])),
  ('lnorm',
   OrderedDict([('kwargs', OrderedDict([('inker_shape', (3, 3)), ('outker_shape', (3, 3)), ('remove_mean', True), ('stretch', 0.1), ('threshold', 0.1)]))]))],
 [('fbcorr',
   OrderedDict([('initialize', OrderedDict([('filter_shape', (9, 9)), ('generate', ('random:uniform', OrderedDict([('rseed', 42)]))), ('n_filters', 64)])), ('kwargs', OrderedDict([('max_out', 1), ('min_out', 0)]))])),
  ('lpool',
   OrderedDict([('kwargs', OrderedDict([('ker_shape', (3, 3)), ('order', 2), ('stride', 1)]))])),
  ('lnorm',
   OrderedDict([('kwargs', OrderedDict([('inker_shape', (3, 3)), ('outker_shape', (3, 3)), ('remove_mean', False), ('stretch', 0.1), ('threshold', 0.1)]))]))]]