def test_create_from_expected_error():
cs = CountSketch.create_from_expected_error(0.0001, 0.01)
assert repr(cs) == "<CountSketch (5 x 271828209)>"
assert len(cs) == 1359141045, 'Unexpected length'
assert cs.sizeof() == 5436564180, 'Unexpected size in bytes'
with pytest.raises(ValueError) as excinfo:
cs = CountSketch.create_from_expected_error(0.001, 2)
assert str(excinfo.value) == 'Error rate shell be in (0, 1)'
with pytest.raises(ValueError) as excinfo:
cs = CountSketch.create_from_expected_error(0.0000000001, 0.02)
assert str(excinfo.value) == 'Deviation is too small. Not enough counters'
def test_init():
cs = CountSketch(2, 4)
assert cs.sizeof() == 32, 'Unexpected size in bytes'
with pytest.raises(ValueError) as excinfo:
cs = CountSketch(0, 5)
assert str(excinfo.value) == 'At least one counter array is required'
with pytest.raises(ValueError) as excinfo:
cs = CountSketch(5, 0)
assert str(excinfo.value) == (
'The length of the counter array cannot be less then 1')
def test_len():
cs = CountSketch(2, 4)
assert len(cs) == 8
def test_frequency():
cs = CountSketch(4, 100)
cs.add("test")
assert cs.frequency("test") == 1, "Can't find recently added element"
assert cs.frequency("test_test") == 0, "False positive detected"
def test_add():
cs = CountSketch(4, 100)
for word in ["test", 1, {"hello": "world"}]:
cs.add(word)
assert cs.frequency(word) == 1, "Can't find frequency for element"
def test_repr():
cs = CountSketch(2, 4)
assert repr(cs) == "<CountSketch (2 x 4)>"
cs = CountSketch.create_from_expected_error(0.1, 0.01)
assert repr(cs) == "<CountSketch (5 x 272)>"
21,
9,
29,
6,
5,
2,
3,
1,
16,
17,
15,
5,
3,
6,
9,
12,
]
if __name__ == '__main__':
cs = CountSketch(5, 2000)
print(cs)
print("CS uses {} bytes in the memory".format(cs.sizeof()))
for digit in DATASET:
cs.add(digit)
for digit in sorted(set(DATASET)):
print("Element: {}. Freq.: {}, Est. Freq.: {}".format(
digit, DATASET.count(digit), cs.frequency(digit)))
def test_size():
cs = CountSketch(2, 4)
element_size = array.array('i', [1]).itemsize
assert cs.sizeof() == element_size * len(cs), "Unexpected size in bytes"