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Issue #11888: Add log2 function to math module. Patch written by Mark

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Dickinson.
This commit is contained in:
Victor Stinner 2011-05-09 01:01:09 +02:00
parent 3de49192aa
commit fa0e3d52d6
6 changed files with 234 additions and 16 deletions
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22
Lib/test/test_math.py
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@ -649,6 +649,28 @@ class MathTests(unittest.TestCase):
n= 2**90
self.assertAlmostEqual(math.log1p(n), math.log1p(float(n)))
@requires_IEEE_754
def testLog2(self):
self.assertRaises(TypeError, math.log2)
# Check that we get exact equality for log2 of powers of 2.
actual = [math.log2(2.0**n) for n in range(-324, 1024)]
expected = [float(n) for n in range(-324, 1024)]
self.assertEqual(actual, expected)
# Check some integer values
self.assertEqual(math.log2(1), 0.0)
self.assertEqual(math.log2(2), 1.0)
self.assertEqual(math.log2(4), 2.0)
# Large integer values
self.assertEqual(math.log2(2**1023), 1023.0)
self.assertEqual(math.log2(2**1024), 1024.0)
self.assertEqual(math.log2(2**2000), 2000.0)
self.assertRaises(ValueError, math.log2, -1.5)
self.assertRaises(ValueError, math.log2, NINF)
self.assertTrue(math.isnan(math.log2(NAN)))
def testLog10(self):
self.assertRaises(TypeError, math.log10)
self.ftest('log10(0.1)', math.log10(0.1), -1)