BUG: internal call fix in random.choice

An random.random call from within mtrand was done by a call to np.random.random instead of inside the class. This can possibly lead to non-deterministic results after seeding.
numpy · certik · Dec 15, 2012 · Nov 13, 2012 · Nov 13, 2012 · Nov 13, 2012
commit eb77c8d75e304da6dd7861a02fd4158db812e8e8
diff --git a/numpy/random/mtrand/mtrand.c b/numpy/random/mtrand/mtrand.c
diff --git a/numpy/random/mtrand/mtrand.pyx b/numpy/random/mtrand/mtrand.pyx
@@ -1026,7 +1026,7 @@ cdef class RandomState:
             if None != p:
                 cdf = p.cumsum()
                 cdf /= cdf[-1]
-                uniform_samples = np.random.random(shape)
+                uniform_samples = self.random_sample(shape)
                 idx = cdf.searchsorted(uniform_samples, side='right')
                 idx = np.array(idx, copy=False) # searchsorted returns a scalar
             else:

diff --git a/numpy/random/tests/test_regression.py b/numpy/random/tests/test_regression.py
@@ -63,5 +63,15 @@ def test_shuffle_mixed_dimension(self):
             random.shuffle(shuffled)
             assert_array_equal(shuffled, [t[0], t[3], t[1], t[2]])
 
+    def test_call_within_randomstate(self):
+        # Check that custom RandomState does not call into global state
+        m = np.random.RandomState()
+        res = np.array([0, 8, 7, 2, 1, 9, 4, 7, 0, 3])
+        for i in range(3):
+            np.random.seed(i)
+            m.seed(4321)
+            # If m.state is not honored, the result will change
+            assert_array_equal(m.choice(10, size=10, p=np.ones(10.)/10), res)
+
 if __name__ == "__main__":
     run_module_suite()