diff options
| -rw-r--r-- | numpy/random/mtrand/mtrand.pyx | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/numpy/random/mtrand/mtrand.pyx b/numpy/random/mtrand/mtrand.pyx index d6ba58bb2..a2cee28b8 100644 --- a/numpy/random/mtrand/mtrand.pyx +++ b/numpy/random/mtrand/mtrand.pyx @@ -4461,8 +4461,21 @@ cdef class RandomState: A loaded dice is more likely to land on number 6: - >>> np.random.multinomial(100, [1/7.]*5) - array([13, 16, 13, 16, 42]) + >>> np.random.multinomial(100, [1/7.]*5 + [2/7.]) + array([11, 16, 14, 17, 16, 26]) + + The probability inputs should already be normalized. The value of the + last entry is always ignored and assumed to take up any leftover + probability mass. To sample a biased coin which has twice as much + weight on one side than the other should *not* be sampled like so: + + >>> np.random.multinomial(100, [1.0, 2.0]) # WRONG + array([100, 0]) + + but rather, like so: + + >>> np.random.multinomial(100, [1.0 / 3, 2.0 / 3]) # RIGHT + array([38, 62]) """ cdef npy_intp d |