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Issue #28469: timeit now uses the sequence 1, 2, 5, 10, 20, 50,... instead 

of 1, 10, 100,... for autoranging.
This commit is contained in:
Serhiy Storchaka 2016-10-23 15:17:05 +03:00
parent f8d7d41507
commit d3ff784f2d
4 changed files with 63 additions and 47 deletions
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23
Doc/library/timeit.rst
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@ -28,11 +28,11 @@ can be used to compare three different expressions:
.. code-block:: sh
$ python3 -m timeit '"-".join(str(n) for n in range(100))'
10000 loops, best of 3: 30.2 usec per loop
10000 loops, best of 5: 30.2 usec per loop
$ python3 -m timeit '"-".join([str(n) for n in range(100)])'
10000 loops, best of 3: 27.5 usec per loop
10000 loops, best of 5: 27.5 usec per loop
$ python3 -m timeit '"-".join(map(str, range(100)))'
10000 loops, best of 3: 23.2 usec per loop
10000 loops, best of 5: 23.2 usec per loop
This can be achieved from the :ref:`python-interface` with::
@ -141,9 +141,8 @@ The module defines three convenience functions and a public class:
This is a convenience function that calls :meth:`.timeit` repeatedly
so that the total time >= 0.2 second, returning the eventual
(number of loops, time taken for that number of loops). It calls
:meth:`.timeit` with *number* set to successive powers of ten (10,
100, 1000, ...) up to a maximum of one billion, until the time taken
is at least 0.2 second, or the maximum is reached.
:meth:`.timeit` with increasing numbers from the sequence 1, 2, 5,
10, 20, 50, ... until the time taken is at least 0.2 second.
If *callback* is given and is not ``None``, it will be called after
each trial with two arguments: ``callback(number, time_taken)``.
@ -268,9 +267,9 @@ It is possible to provide a setup statement that is executed only once at the be
.. code-block:: sh
$ python -m timeit -s 'text = "sample string"; char = "g"' 'char in text'
10000000 loops, best of 3: 0.0877 usec per loop
5000000 loops, best of 5: 0.0877 usec per loop
$ python -m timeit -s 'text = "sample string"; char = "g"' 'text.find(char)'
1000000 loops, best of 3: 0.342 usec per loop
1000000 loops, best of 5: 0.342 usec per loop
::
@ -297,14 +296,14 @@ to test for missing and present object attributes:
.. code-block:: sh
$ python -m timeit 'try:' ' str.__bool__' 'except AttributeError:' ' pass'
100000 loops, best of 3: 15.7 usec per loop
20000 loops, best of 5: 15.7 usec per loop
$ python -m timeit 'if hasattr(str, "__bool__"): pass'
100000 loops, best of 3: 4.26 usec per loop
50000 loops, best of 5: 4.26 usec per loop
$ python -m timeit 'try:' ' int.__bool__' 'except AttributeError:' ' pass'
1000000 loops, best of 3: 1.43 usec per loop
200000 loops, best of 5: 1.43 usec per loop
$ python -m timeit 'if hasattr(int, "__bool__"): pass'
100000 loops, best of 3: 2.23 usec per loop
100000 loops, best of 5: 2.23 usec per loop
::

59
Lib/test/test_timeit.py
View File

@ -256,7 +256,7 @@ class TestTimeit(unittest.TestCase):
def test_main_milliseconds(self):
s = self.run_main(seconds_per_increment=0.0055)
self.assertEqual(s, "100 loops, best of 5: 5.5 msec per loop\n")
self.assertEqual(s, "50 loops, best of 5: 5.5 msec per loop\n")
def test_main_microseconds(self):
s = self.run_main(seconds_per_increment=0.0000025, switches=['-n100'])
@ -304,35 +304,43 @@ class TestTimeit(unittest.TestCase):
"""))
def test_main_very_verbose(self):
s = self.run_main(seconds_per_increment=0.000050, switches=['-vv'])
s = self.run_main(seconds_per_increment=0.000_030, switches=['-vv'])
self.assertEqual(s, dedent("""\
1 loop -> 5e-05 secs
10 loops -> 0.0005 secs
100 loops -> 0.005 secs
1000 loops -> 0.05 secs
10000 loops -> 0.5 secs
1 loop -> 3e-05 secs
2 loops -> 6e-05 secs
5 loops -> 0.00015 secs
10 loops -> 0.0003 secs
20 loops -> 0.0006 secs
50 loops -> 0.0015 secs
100 loops -> 0.003 secs
200 loops -> 0.006 secs
500 loops -> 0.015 secs
1000 loops -> 0.03 secs
2000 loops -> 0.06 secs
5000 loops -> 0.15 secs
10000 loops -> 0.3 secs
raw times: 500 msec, 500 msec, 500 msec, 500 msec, 500 msec
raw times: 300 msec, 300 msec, 300 msec, 300 msec, 300 msec
10000 loops, best of 5: 50 usec per loop
10000 loops, best of 5: 30 usec per loop
"""))
def test_main_with_time_unit(self):
unit_sec = self.run_main(seconds_per_increment=0.002,
unit_sec = self.run_main(seconds_per_increment=0.003,
switches=['-u', 'sec'])
self.assertEqual(unit_sec,
"100 loops, best of 5: 0.002 sec per loop\n")
unit_msec = self.run_main(seconds_per_increment=0.002,
"100 loops, best of 5: 0.003 sec per loop\n")
unit_msec = self.run_main(seconds_per_increment=0.003,
switches=['-u', 'msec'])
self.assertEqual(unit_msec,
"100 loops, best of 5: 2 msec per loop\n")
unit_usec = self.run_main(seconds_per_increment=0.002,
"100 loops, best of 5: 3 msec per loop\n")
unit_usec = self.run_main(seconds_per_increment=0.003,
switches=['-u', 'usec'])
self.assertEqual(unit_usec,
"100 loops, best of 5: 2e+03 usec per loop\n")
"100 loops, best of 5: 3e+03 usec per loop\n")
# Test invalid unit input
with captured_stderr() as error_stringio:
invalid = self.run_main(seconds_per_increment=0.002,
invalid = self.run_main(seconds_per_increment=0.003,
switches=['-u', 'parsec'])
self.assertEqual(error_stringio.getvalue(),
"Unrecognized unit. Please select nsec, usec, msec, or sec.\n")
@ -347,15 +355,15 @@ class TestTimeit(unittest.TestCase):
s = self.run_main(switches=['-n1', '1/0'])
self.assert_exc_string(error_stringio.getvalue(), 'ZeroDivisionError')
def autorange(self, seconds_per_increment=0.001, callback=None):
def autorange(self, seconds_per_increment=1/1024, callback=None):
timer = FakeTimer(seconds_per_increment=seconds_per_increment)
t = timeit.Timer(stmt=self.fake_stmt, setup=self.fake_setup, timer=timer)
return t.autorange(callback)
def test_autorange(self):
num_loops, time_taken = self.autorange()
self.assertEqual(num_loops, 1000)
self.assertEqual(time_taken, 1.0)
self.assertEqual(num_loops, 500)
self.assertEqual(time_taken, 500/1024)
def test_autorange_second(self):
num_loops, time_taken = self.autorange(seconds_per_increment=1.0)
@ -367,12 +375,17 @@ class TestTimeit(unittest.TestCase):
print("{} {:.3f}".format(a, b))
with captured_stdout() as s:
num_loops, time_taken = self.autorange(callback=callback)
self.assertEqual(num_loops, 1000)
self.assertEqual(time_taken, 1.0)
self.assertEqual(num_loops, 500)
self.assertEqual(time_taken, 500/1024)
expected = ('1 0.001\n'
'2 0.002\n'
'5 0.005\n'
'10 0.010\n'
'100 0.100\n'
'1000 1.000\n')
'20 0.020\n'
'50 0.049\n'
'100 0.098\n'
'200 0.195\n'
'500 0.488\n')
self.assertEqual(s.getvalue(), expected)

25
Lib/timeit.py
View File

@ -208,22 +208,23 @@ class Timer:
def autorange(self, callback=None):
"""Return the number of loops so that total time >= 0.2.
Calls the timeit method with *number* set to successive powers of
ten (10, 100, 1000, ...) up to a maximum of one billion, until
the time taken is at least 0.2 second, or the maximum is reached.
Returns ``(number, time_taken)``.
Calls the timeit method with increasing numbers from the sequence
1, 2, 5, 10, 20, 50, ... until the time taken is at least 0.2
second. Returns (number, time_taken).
If *callback* is given and is not None, it will be called after
each trial with two arguments: ``callback(number, time_taken)``.
"""
for i in range(0, 10):
number = 10**i
time_taken = self.timeit(number)
if callback:
callback(number, time_taken)
if time_taken >= 0.2:
break
return (number, time_taken)
i = 1
while True:
for j in 1, 2, 5:
number = i * j
time_taken = self.timeit(number)
if callback:
callback(number, time_taken)
if time_taken >= 0.2:
return (number, time_taken)
i *= 10
def timeit(stmt="pass", setup="pass", timer=default_timer,
number=default_number, globals=None):

3
Misc/NEWS
View File

@ -97,6 +97,9 @@ Core and Builtins
Library
-------
- Issue #28469: timeit now uses the sequence 1, 2, 5, 10, 20, 50,... instead
of 1, 10, 100,... for autoranging.
- Issue #28115: Command-line interface of the zipfile module now uses argparse.
Added support of long options.