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| author | Guido van Rossum <guido@python.org> | 1997-12-02 02:47:39 (GMT) |
|---|---|---|
| committer | Guido van Rossum <guido@python.org> | 1997-12-02 02:47:39 (GMT) |
| commit | cf4559a62ec9316a3bb55a67c6fca81ec1ad0d18 (patch) | |
| tree | 0eaae870304815719e40986151f33eee6989065c /Lib/random.py | |
| parent | c99a239f4277b76fcdcc85772847d07fa49cf10a (diff) | |
| download | cpython-cf4559a62ec9316a3bb55a67c6fca81ec1ad0d18.zip cpython-cf4559a62ec9316a3bb55a67c6fca81ec1ad0d18.tar.gz cpython-cf4559a62ec9316a3bb55a67c6fca81ec1ad0d18.tar.bz2 | |
Added Pareto and Weibull distributions, courtesy Jeremy Hylton.
Diffstat (limited to 'Lib/random.py')
| -rw-r--r-- | Lib/random.py | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/Lib/random.py b/Lib/random.py index 608203f..52a4266 100644 --- a/Lib/random.py +++ b/Lib/random.py @@ -212,6 +212,22 @@ def betavariate(alpha, beta): z = expovariate(1.0/beta) return z/(y+z) +# -------------------- pareto -------------------- + +def paretovariate(alpha): + # Jain, pg. 495 + + u = random() + return 1.0 / pow(u, 1.0/alpha) + +# -------------------- pareto -------------------- + +def weibullvariate(alpha, beta): + # Jain, pg. 499; bug fix courtesy Bill Arms + + u = random() + return alpha * pow(-log(u), 1.0/beta) + # -------------------- test program -------------------- def test(N = 200): @@ -233,6 +249,8 @@ def test(N = 200): test_generator(N, 'gammavariate(200.0, 1.0)') test_generator(N, 'gauss(0.0, 1.0)') test_generator(N, 'betavariate(3.0, 3.0)') + test_generator(N, 'paretovariate(1.0)') + test_generator(N, 'weibullvariate(1.0, 1.0)') def test_generator(n, funccall): import time |