def test_kfold_random_stable(seed):
random.seed(seed)
k = 2 + int(random.expovariate(0.2))
n = k + int(random.expovariate(0.000001))
splits1 = kfold_random(nrows=n, nsplits=k, seed=seed)
with dt.options.context(nthreads=dt.options.nthreads // 2):
splits2 = kfold_random(nrows=n, nsplits=k, seed=seed)
assert len(splits1) == len(splits2) == k
for i in range(k):
assert len(splits1[i]) == len(splits2[i]) == 2
for j in range(2):
values1 = splits1[i][j].to_list()[0]
values2 = splits2[i][j].to_list()[0]
assert values1 == values2
def test_kfold_random_bad_args():
assert_value_error(lambda: kfold_random(nrows=-1, nsplits=1),
"Argument `nrows` in kfold_random() cannot be negative")
assert_value_error(lambda: kfold_random(nrows=3, nsplits=-3),
"Argument `nsplits` in kfold_random() cannot be negative")
assert_value_error(lambda: kfold_random(nrows=10, nsplits=3, seed=-1),
"Argument `seed` in kfold_random() cannot be negative")
assert_value_error(lambda: kfold_random(nrows=5, nsplits=0),
"The number of splits cannot be less than two")
assert_value_error(lambda: kfold_random(nrows=1, nsplits=2),
"The number of splits cannot exceed the number of rows")
def test_kfold_random_any(seed):
random.seed(seed)
k = 2 + int(random.expovariate(0.01))
n = k + int(random.expovariate(0.0001))
splits = kfold_random(nrows=n, nsplits=k, seed=seed)
assert isinstance(splits, list) and len(splits) == k
all_folds = []
for split in splits:
assert isinstance(split, tuple) and len(split) == 2
train, test = split
assert isinstance(train, dt.Frame)
assert isinstance(test, dt.Frame)
assert train.stypes == (dt.int32,)
assert test.stypes == (dt.int32,)
assert train.ncols == 1
assert test.ncols == 1
assert train.nrows + test.nrows == n
assert test.nrows in [n//k, n//k + 1]
train_data = train.to_list()[0]
test_data = test.to_list()[0]
assert train_data == sorted(train_data)
assert test_data == sorted(test_data)
train_set = set(train_data)
test_set = set(test_data)
assert len(train_set) == train.nrows
assert len(test_set) == test.nrows
assert (train_set | test_set) == set(range(n))
all_folds += test_data
all_folds.sort()
assert all_folds == list(range(n))
def test_kfold_random_2_2():
splits = kfold_random(nrows=2, nsplits=2)
assert isinstance(splits, list) and len(splits) == 2
assert all(isinstance(s, tuple) and len(s) == 2 for s in splits)
assert all(s[0].shape == (1, 1) and s[1].shape == (1, 1) for s in splits)
a = splits[0][0][0, 0]
assert a == 0 or a == 1
assert splits[0][1][0, 0] == 1 - a
assert splits[1][0][0, 0] == 1 - a
assert splits[1][1][0, 0] == a
def test_kfold_random_bad_args():
msg = r"Argument nrows in function datatable.kfold_random\(\) cannot be negative"
with pytest.raises(ValueError, match=msg):
kfold_random(nrows=-1, nsplits=1)
msg = r"Argument nsplits in function datatable.kfold_random\(\) cannot be negative"
with pytest.raises(ValueError, match=msg):
kfold_random(nrows=3, nsplits=-3)
msg = r"Argument seed in function datatable.kfold_random\(\) cannot be negative"
with pytest.raises(ValueError, match=msg):
kfold_random(nrows=10, nsplits=3, seed=-1)
msg = "The number of splits cannot be less than two"
with pytest.raises(ValueError, match=msg):
kfold_random(nrows=5, nsplits=0)
msg = "The number of splits cannot exceed the number of rows"
with pytest.raises(ValueError, match=msg):
kfold_random(nrows=1, nsplits=2)
def test_kfold_random_api():
assert_type_error(lambda: kfold_random(),
"Required parameter `nrows` is missing")
assert_type_error(lambda: kfold_random(nrows=5, seed=12345678),
"Required parameter `nsplits` is missing")
assert_type_error(lambda: kfold_random(5, 2),
"kfold_random() takes no positional arguments, but 2 were given")
assert_type_error(lambda: kfold_random(nrows=5, nsplits=3.3),
"Argument `nsplits` in kfold_random() should be an integer")
assert_type_error(lambda: kfold_random(nrows=None, nsplits=7),
"Argument `nrows` in kfold_random() should be an integer")
assert_type_error(lambda: kfold_random(nrows=5, nsplits=2, seed="boo"),
"Argument `seed` in kfold_random() should be an integer")
def test_kfold_random_api():
msg = "Required parameter nrows is missing"
with pytest.raises(TypeError, match=msg):
kfold_random()
msg = "Required parameter nsplits is missing"
with pytest.raises(TypeError, match=msg):
kfold_random(nrows=5, seed=12345678)
msg = r"kfold_random\(\) takes no positional arguments, but 2 were given"
with pytest.raises(TypeError, match=msg):
kfold_random(5, 2)
msg = r"Argument nsplits in function datatable.kfold_random\(\) should be an integer"
with pytest.raises(TypeError, match=msg):
kfold_random(nrows=5, nsplits=3.3)
msg = r"Argument nrows in function datatable.kfold_random\(\) should be an integer"
with pytest.raises(TypeError, match=msg):
kfold_random(nrows=None, nsplits=7)
msg = r"Argument seed in function datatable.kfold_random\(\) should be an integer"
with pytest.raises(TypeError, match=msg):
kfold_random(nrows=5, nsplits=2, seed="boo")
