Reference: https://svn.python.org/projects/python/trunk/Lib/random.py
| 20 | import uuid |
| 21 | |
| 22 | class WichmannHill(random.Random): |
| 23 | """ |
| 24 | Reference: https://svn.python.org/projects/python/trunk/Lib/random.py |
| 25 | """ |
| 26 | |
| 27 | VERSION = 1 # used by getstate/setstate |
| 28 | |
| 29 | def seed(self, a=None): |
| 30 | """Initialize internal state from hashable object. |
| 31 | |
| 32 | None or no argument seeds from current time or from an operating |
| 33 | system specific randomness source if available. |
| 34 | |
| 35 | If a is not None or an int or long, hash(a) is used instead. |
| 36 | |
| 37 | If a is an int or long, a is used directly. Distinct values between |
| 38 | 0 and 27814431486575L inclusive are guaranteed to yield distinct |
| 39 | internal states (this guarantee is specific to the default |
| 40 | Wichmann-Hill generator). |
| 41 | """ |
| 42 | |
| 43 | if a is None: |
| 44 | try: |
| 45 | a = int(binascii.hexlify(os.urandom(16)), 16) |
| 46 | except NotImplementedError: |
| 47 | a = int(time.time() * 256) # use fractional seconds |
| 48 | |
| 49 | if not isinstance(a, int): |
| 50 | a = hash(a) |
| 51 | |
| 52 | a, x = divmod(a, 30268) |
| 53 | a, y = divmod(a, 30306) |
| 54 | a, z = divmod(a, 30322) |
| 55 | self._seed = int(x) + 1, int(y) + 1, int(z) + 1 |
| 56 | |
| 57 | self.gauss_next = None |
| 58 | |
| 59 | def random(self): |
| 60 | """Get the next random number in the range [0.0, 1.0).""" |
| 61 | |
| 62 | # Wichman-Hill random number generator. |
| 63 | # |
| 64 | # Wichmann, B. A. & Hill, I. D. (1982) |
| 65 | # Algorithm AS 183: |
| 66 | # An efficient and portable pseudo-random number generator |
| 67 | # Applied Statistics 31 (1982) 188-190 |
| 68 | # |
| 69 | # see also: |
| 70 | # Correction to Algorithm AS 183 |
| 71 | # Applied Statistics 33 (1984) 123 |
| 72 | # |
| 73 | # McLeod, A. I. (1985) |
| 74 | # A remark on Algorithm AS 183 |
| 75 | # Applied Statistics 34 (1985),198-200 |
| 76 | |
| 77 | # This part is thread-unsafe: |
| 78 | # BEGIN CRITICAL SECTION |
| 79 | x, y, z = self._seed |
no outgoing calls
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