Add Python code to Monte Carlo Integration

contents/monte_carlo_integration/code/python/monte_carlo.py

@@ -0,0 +1,35 @@
+# submitted by hybrideagle
+from random import random
+from math import pi
+
+
+def inCircle(xPos, yPos):
+    radius = 1
+    # Compute euclidian distance from origin
+    return (xPos * xPos + yPos * yPos) < (radius * radius)
+
+
+def monteCarlo(n):
+    """
+    Computes PI using the monte carlo method using `n` points 
+    """
+    piCount = 0
+
+    for i in range(n):
+        pointX = random()
+        pointY = random()
+        if inCircle(pointX, pointY):
+            piCount += 1
+
+    # This is using a quarter of the unit sphere in a 1x1 box.
+    # The formula is pi = (boxLength^2 / radius^2) * (piCount / n), but we
+    # are only using the upper quadrant and the unit circle, so we can use
+    # 4*piCount/n instead
+    # piEstimate = 4*piCount/n
+    piEstimate = 4 * piCount / n
+    print('Pi is {0:} ({1:.4f}% error)'.format(
+        piEstimate, (pi - piEstimate) / pi * 100))
+
+
+if __name__ == "__main__":
+    monteCarlo(100000)

contents/monte_carlo_integration/monte_carlo_integration.md

@@ -59,6 +59,8 @@ each point is tested to see whether it's in the circle or not:
 [import:13-15, lang:"java"](code/java/MonteCarlo.java)
 {% sample lang="swift" %}
 [import:15-17 lang:"swift"](code/swift/monte_carlo.swift)
+{% sample lang="python" %}
+[import:6-10 lang:"python"](code/python/monte_carlo.python)
 {% endmethod %}
 
 If it's in the circle, we increase an internal count by one, and in the end,
@@ -112,6 +114,8 @@ Feel free to submit your version via pull request, and thanks for reading!
 [import, lang:"java"](code/java/MonteCarlo.java)
 {% sample lang="swift" %}
 [import, lang:"swift"](code/swift/monte_carlo.swift)
+{% sample lang="python" %}
+[import, lang:"python"](code/python/monte_carlo.python)
 {% endmethod %}