8000 Merge pull request #18482 from bashtage/multinomial-pvals-err · numpy/numpy@9a2a786 · GitHub
[go: up one dir, main page]
Skip to content

Commit 9a2a786

Browse files
charrischarris
authored
Merge pull request #18482 from bashtage/multinomial-pvals-err
ENH: Improve error message in multinomial
2 parents 7d3b555 + b1015ad<
8000
/a> commit 9a2a786

4 files changed

+44
-2
lines changed

‎numpy/random/_generator.pyx

Lines changed: 14 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -3756,7 +3756,20 @@ cdef class Generator:
37563756
pix = <double*>np.PyArray_DATA(parr)
37573757
check_array_constraint(parr, 'pvals', CONS_BOUNDED_0_1)
37583758
if kahan_sum(pix, d-1) > (1.0 + 1e-12):
3759-
raise ValueError("sum(pvals[:-1]) > 1.0")
3759+
# When floating, but not float dtype, and close, improve the error
3760+
# 1.0001 works for float16 and float32
3761+
if (isinstance(pvals, np.ndarray)
3762+
and np.issubdtype(pvals.dtype, np.floating)
3763+
and pvals.dtype != float
3764+
and pvals.sum() < 1.0001):
3765+
msg = ("sum(pvals[:-1].astype(np.float64)) > 1.0. The pvals "
3766+
"array is cast to 64-bit floating point prior to "
3767+
"checking the sum. Precision changes when casting may "
3768+
"cause problems even if the sum of the original pvals "
3769+
"is valid.")
3770+
else:
3771+
msg = "sum(pvals[:-1]) > 1.0"
3772+
raise ValueError(msg)
37603773

37613774
if np.PyArray_NDIM(on) != 0: # vector
37623775
check_array_constraint(on, 'n', CONS_NON_NEGATIVE)

‎numpy/random/mtrand.pyx

Lines changed: 14 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -4232,7 +4232,20 @@ cdef class RandomState:
42324232
pix = <double*>np.PyArray_DATA(parr)
42334233
check_array_constraint(parr, 'pvals', CONS_BOUNDED_0_1)
42344234
if kahan_sum(pix, d-1) > (1.0 + 1e-12):
4235-
raise ValueError("sum(pvals[:-1]) > 1.0")
4235+
# When floating, but not float dtype, and close, improve the error
4236+
# 1.0001 works for float16 and float32
4237+
if (isinstance(pvals, np.ndarray)
4238+
and np.issubdtype(pvals.dtype, np.floating)
4239+
and pvals.dtype != float
4240+
and pvals.sum() < 1.0001):
4241+
msg = ("sum(pvals[:-1].astype(np.float64)) > 1.0. The pvals "
4242+
"array is cast to 64-bit floating point prior to "
4243+
"checking the sum. Precision changes when casting may "
4244+
"cause problems even if the sum of the original pvals "
4245+
"is valid.")
4246+
else:
4247+
msg = "sum(pvals[:-1]) > 1.0"
4248+
raise ValueError(msg)
42364249

42374250
if size is None:
42384251
shape = (d,)

‎numpy/random/tests/test_generator_mt19937.py

Lines changed: 8 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -142,6 +142,14 @@ def test_multidimensional_pvals(self):
142142
assert_raises(ValueError, random.multinomial, 10, [[[0], [1]], [[1], [0]]])
143143
assert_raises(ValueError, random.multinomial, 10, np.array([[0, 1], [1, 0]]))
144144

145+
def test_multinomial_pvals_float32(self):
146+
x = np.array([9.9e-01, 9.9e-01, 1.0e-09, 1.0e-09, 1.0e-09, 1.0e-09,
147+
1.0e-09, 1.0e-09, 1.0e-09, 1.0e-09], dtype=np.float32)
148+
pvals = x / x.sum()
149+
random = Generator(MT19937(1432985819))
150+
match = r"[\w\s]*pvals array is cast to 64-bit floating"
151+
with pytest.raises(ValueError, match=match):
152+
random.multinomial(1, pvals)
145153

146154
class TestMultivariateHypergeometric:
147155

‎numpy/random/tests/test_randomstate.py

Lines changed: 8 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -167,6 +167,14 @@ def test_p_non_contiguous(self):
167167
contig = random.multinomial(100, pvals=np.ascontiguousarray(pvals))
168168
assert_array_equal(non_contig, contig)
169169

170+
def test_multinomial_pvals_float32(self):
171+
x = np.array([9.9e-01, 9.9e-01, 1.0e-09, 1.0e-09, 1.0e-09, 1.0e-09,
172+
1.0e-09, 1.0e-09, 1.0e-09, 1.0e-09], dtype=np.float32)
173+
pvals = x / x.sum()
174+
match = r"[\w\s]*pvals array is cast to 64-bit floating"
175+
with pytest.raises(ValueError, match=match):
176+
random.multinomial(1, pvals)
177+
170178

171179
class TestSetState:
172180
def setup(self):

0 commit comments

Comments
 (0)
0