Implement random.paretovariate()

Author: namannimmo10

integration_tests/test_random.py

@@ -21,5 +21,13 @@ def test_randint():
     print(ri2)
     assert ri2 >= -50 and ri2 <= 76
 
+def test_paretovariate():
+    r: f64
+    r = random.paretovariate(2.0)
+    print(r)
+    r = random.paretovariate(-5.6)
+    print(r)
+
 test_random()
 test_randint()
+test_paretovariate()

src/runtime/random.py

@@ -1,5 +1,6 @@
 from ltypes import i32, f64, ccall
 
+
 def random() -> f64:
     """
     Returns a random floating point number in the range [0.0, 1.0)
@@ -19,3 +20,11 @@ def randint(lower: i32, upper: i32) -> i32:
 @ccall
 def _lfortran_random_int(lower: i32, upper: i32) -> i32:
     pass
+
+def paretovariate(alpha: f64) -> f64:
+    """
+    Return a random number from a Pareto distribution with parameter `alpha`.
+    """
+    u: f64
+    u = 1.0 - random()
+    return u ** (-1.0 / alpha)