Feat(Core/API): Random generation methods for numbers

mapytex/calculus/core/random.py

@@ -0,0 +1,119 @@
+#! /usr/bin/env python
+# -*- coding: utf-8 -*-
+# vim:fenc=utf-8
+#
+# Copyright © 2017 lafrite <lafrite@Poivre>
+#
+# Distributed under terms of the MIT license.
+
+"""
+Function to create random things
+
+"""
+from random import randint, choice
+
+__all__ = ["reject_random", "filter_random", "FilterRandom"]
+
+def reject_random(min_value = -10, 
+           max_value = 10,
+           rejected = [0, 1],
+           accept_callbacks=[],
+           ):
+    """ Generate a random integer with the rejection method
+
+        :param name: name of the Integer
+        :param min_value: minimum value
+        :param max_value: maximum value
+        :param rejected: rejected values
+        :param accept_callbacks: list of function for value rejection
+
+    """
+    conditions = [lambda x: x not in rejected] + accept_callbacks
+
+    candidate = randint(min_value, max_value)
+    while not all(c(candidate) for c in conditions):
+        candidate = randint(min_value, max_value)
+
+    return candidate
+
+def filter_random(min_value = -10,
+           max_value = 10,
+           rejected = [0, 1],
+           accept_callbacks=[],
+           ):
+    """ Generate a random integer by filtering then choosing a candidate
+
+        :param name: name of the Integer
+        :param min_value: minimum value
+        :param max_value: maximum value
+        :param rejected: rejected values
+        :param accept_callbacks: list of function for value rejection
+
+    """
+    candidates = set(range(min_value, max_value+1))
+    candidates = {c for c in candidates if c not in rejected}
+
+    candidates = [candidate for candidate in candidates \
+                  if all(c(candidate) for c in accept_callbacks)]
+
+    if len(candidates) == 0:
+        raise OverflowError("There is no candidates for this range and those conditions")
+    return choice(candidates)
+
+class FilterRandom(object):
+
+    """ Integer random generator which filter then choose candidate
+    """
+    # TODO: Faire un cache pour éviter de reconstruire les listes à chaque fois |ven. déc. 21 19:07:42 CET 2018
+
+    def __init__(self,
+                 rejected = [0, 1],
+                 accept_callbacks=[],
+                 min_value = -10, 
+                 max_value = 10,
+                 ):
+        self.conditions = (lambda x: x not in rejected,) + tuple(accept_callbacks)
+
+        self._min = min_value
+        self._max = max_value
+
+        candidates = set(range(self._min, self._max+1))
+
+        self._candidates = { candidate for candidate in candidates \
+            if all(c(candidate) for c in self.conditions) }
+
+    def add_candidates(self, low, high):
+        """ Add candidates between low and high to _candidates """
+        if low < self._min:
+            self._min = low
+            useless_low = False
+        else:
+            useless_low = True
+        if high > self._max:
+            self._max = high
+            useless_high = False
+        else:
+            useless_high = True
+
+        if not(useless_low and useless_high):
+            candidates = set(range(low, high+1))
+
+            self._candidates = self._candidates.union({
+                candidate for candidate in candidates \
+                if all(c(candidate) for c in self.conditions) \
+            })
+
+    def candidates(self, min_value=-10, max_value=10):
+        """ Return candidates between min_value and max_value """
+        return [c for c in self._candidates if (c > min_value and c < max_value)]
+
+    def __call__(self, min_value=-10, max_value=10):
+        """ Randomly choose on candidate """
+        self.add_candidates(min_value, max_value)
+        return choice(self.candidates(min_value, max_value))
+
+
+# -----------------------------
+# Reglages pour 'vim'
+# vim:set autoindent expandtab tabstop=4 shiftwidth=4:
+# cursor: 16 del