Data commit

Task/Modified-random-distribution/Nim/modified-random-distribution.nim

@@ -0,0 +1,34 @@
+import random, strformat, strutils, sugar
+
+type ValRange = range[0.0..1.0]
+
+func modifier(x: ValRange): ValRange =
+  if x < 0.5: 2 * (0.5 - x) else: 2 * (x - 0.5)
+
+proc rand(modifier: (float) -> float): ValRange =
+  while true:
+    let r1 = rand(1.0)
+    let r2 = rand(1.0)
+    if r2 < modifier(r1):
+      return r1
+
+const
+  N = 100_000
+  NumBins = 20
+  HistChar = "■"
+  HistCharSize = 125
+  BinSize = 1 / NumBins
+
+randomize()
+
+var bins: array[NumBins, int]
+for i in 0..<N:
+  let rn = rand(modifier)
+  let bn = int(rn / BinSize)
+  inc bins[bn]
+
+echo &"Modified random distribution with {N} samples in range [0, 1):"
+echo "    Range           Number of samples within that range"
+for i in 0..<NumBins:
+  let hist = repeat(HistChar, (bins[i] / HistCharSize).toInt)
+  echo &"{BinSize * float(i):4.2f} ..< {BinSize * float(i + 1):4.2f}  {hist} {bins[i]}"