Initial data commit

Task/Modified-random-distribution/Python/modified-random-distribution.py

@@ -0,0 +1,63 @@
+import random
+from typing import List, Callable, Optional
+
+
+def modifier(x: float) -> float:
+    """
+    V-shaped, modifier(x) goes from 1 at 0 to 0 at 0.5 then back to 1 at 1.0 .
+
+    Parameters
+    ----------
+    x : float
+        Number, 0.0 .. 1.0 .
+
+    Returns
+    -------
+    float
+        Target probability for generating x; between 0 and 1.
+
+    """
+    return 2*(.5 - x) if x < 0.5 else 2*(x - .5)
+
+
+def modified_random_distribution(modifier: Callable[[float], float],
+                                 n: int) -> List[float]:
+    """
+    Generate n random numbers between 0 and 1 subject to modifier.
+
+    Parameters
+    ----------
+    modifier : Callable[[float], float]
+        Target random number gen. 0 <= modifier(x) < 1.0 for 0 <= x < 1.0 .
+    n : int
+        number of random numbers generated.
+
+    Returns
+    -------
+    List[float]
+        n random numbers generated with given probability.
+
+    """
+    d: List[float] = []
+    while len(d) < n:
+        r1 = prob = random.random()
+        if random.random() < modifier(prob):
+            d.append(r1)
+    return d
+
+
+if __name__ == '__main__':
+    from collections import Counter
+
+    data = modified_random_distribution(modifier, 50_000)
+    bins = 15
+    counts = Counter(d // (1 / bins) for d in data)
+    #
+    mx = max(counts.values())
+    print("   BIN, COUNTS, DELTA: HISTOGRAM\n")
+    last: Optional[float] = None
+    for b, count in sorted(counts.items()):
+        delta = 'N/A' if last is None else str(count - last)
+        print(f"  {b / bins:5.2f},  {count:4},  {delta:>4}: "
+              f"{'#' * int(40 * count / mx)}")
+        last = count