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	 1919b7e72b
			
		
	
	
		1919b7e72b
		
	
	
	
	
		
			
			up the decimal module. Performance gains of the new C implementation are between 12x and 80x, depending on the application.
		
			
				
	
	
		
			250 lines
		
	
	
	
		
			9.4 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			250 lines
		
	
	
	
		
			9.4 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
| # Copyright (c) 2010 Python Software Foundation. All Rights Reserved.
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| # Adapted from Python's Lib/test/test_strtod.py (by Mark Dickinson)
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| 
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| # More test cases for deccheck.py.
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| 
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| import random
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| 
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| TEST_SIZE = 2
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| 
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| 
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| def test_short_halfway_cases():
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|     # exact halfway cases with a small number of significant digits
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|     for k in 0, 5, 10, 15, 20:
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|         # upper = smallest integer >= 2**54/5**k
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|         upper = -(-2**54//5**k)
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|         # lower = smallest odd number >= 2**53/5**k
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|         lower = -(-2**53//5**k)
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|         if lower % 2 == 0:
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|             lower += 1
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|         for i in range(10 * TEST_SIZE):
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|             # Select a random odd n in [2**53/5**k,
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|             # 2**54/5**k). Then n * 10**k gives a halfway case
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|             # with small number of significant digits.
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|             n, e = random.randrange(lower, upper, 2), k
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| 
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|             # Remove any additional powers of 5.
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|             while n % 5 == 0:
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|                 n, e = n // 5, e + 1
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|             assert n % 10 in (1, 3, 7, 9)
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| 
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|             # Try numbers of the form n * 2**p2 * 10**e, p2 >= 0,
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|             # until n * 2**p2 has more than 20 significant digits.
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|             digits, exponent = n, e
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|             while digits < 10**20:
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|                 s = '{}e{}'.format(digits, exponent)
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|                 yield s
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|                 # Same again, but with extra trailing zeros.
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|                 s = '{}e{}'.format(digits * 10**40, exponent - 40)
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|                 yield s
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|                 digits *= 2
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| 
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|             # Try numbers of the form n * 5**p2 * 10**(e - p5), p5
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|             # >= 0, with n * 5**p5 < 10**20.
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|             digits, exponent = n, e
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|             while digits < 10**20:
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|                 s = '{}e{}'.format(digits, exponent)
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|                 yield s
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|                 # Same again, but with extra trailing zeros.
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|                 s = '{}e{}'.format(digits * 10**40, exponent - 40)
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|                 yield s
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|                 digits *= 5
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|                 exponent -= 1
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| 
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| def test_halfway_cases():
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|     # test halfway cases for the round-half-to-even rule
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|     for i in range(1000):
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|         for j in range(TEST_SIZE):
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|             # bit pattern for a random finite positive (or +0.0) float
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|             bits = random.randrange(2047*2**52)
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| 
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|             # convert bit pattern to a number of the form m * 2**e
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|             e, m = divmod(bits, 2**52)
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|             if e:
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|                 m, e = m + 2**52, e - 1
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|             e -= 1074
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| 
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|             # add 0.5 ulps
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|             m, e = 2*m + 1, e - 1
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| 
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|             # convert to a decimal string
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|             if e >= 0:
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|                 digits = m << e
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|                 exponent = 0
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|             else:
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|                 # m * 2**e = (m * 5**-e) * 10**e
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|                 digits = m * 5**-e
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|                 exponent = e
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|             s = '{}e{}'.format(digits, exponent)
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|             yield s
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| 
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| def test_boundaries():
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|     # boundaries expressed as triples (n, e, u), where
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|     # n*10**e is an approximation to the boundary value and
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|     # u*10**e is 1ulp
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|     boundaries = [
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|         (10000000000000000000, -19, 1110),   # a power of 2 boundary (1.0)
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|         (17976931348623159077, 289, 1995),   # overflow boundary (2.**1024)
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|         (22250738585072013831, -327, 4941),  # normal/subnormal (2.**-1022)
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|         (0, -327, 4941),                     # zero
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|         ]
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|     for n, e, u in boundaries:
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|         for j in range(1000):
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|             for i in range(TEST_SIZE):
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|                 digits = n + random.randrange(-3*u, 3*u)
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|                 exponent = e
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|                 s = '{}e{}'.format(digits, exponent)
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|                 yield s
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|             n *= 10
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|             u *= 10
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|             e -= 1
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| 
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| def test_underflow_boundary():
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|     # test values close to 2**-1075, the underflow boundary; similar
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|     # to boundary_tests, except that the random error doesn't scale
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|     # with n
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|     for exponent in range(-400, -320):
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|         base = 10**-exponent // 2**1075
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|         for j in range(TEST_SIZE):
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|             digits = base + random.randrange(-1000, 1000)
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|             s = '{}e{}'.format(digits, exponent)
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|             yield s
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| 
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| def test_bigcomp():
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|     for ndigs in 5, 10, 14, 15, 16, 17, 18, 19, 20, 40, 41, 50:
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|         dig10 = 10**ndigs
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|         for i in range(100 * TEST_SIZE):
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|             digits = random.randrange(dig10)
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|             exponent = random.randrange(-400, 400)
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|             s = '{}e{}'.format(digits, exponent)
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|             yield s
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| 
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| def test_parsing():
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|     # make '0' more likely to be chosen than other digits
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|     digits = '000000123456789'
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|     signs = ('+', '-', '')
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| 
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|     # put together random short valid strings
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|     # \d*[.\d*]?e
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|     for i in range(1000):
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|         for j in range(TEST_SIZE):
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|             s = random.choice(signs)
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|             intpart_len = random.randrange(5)
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|             s += ''.join(random.choice(digits) for _ in range(intpart_len))
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|             if random.choice([True, False]):
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|                 s += '.'
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|                 fracpart_len = random.randrange(5)
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|                 s += ''.join(random.choice(digits)
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|                              for _ in range(fracpart_len))
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|             else:
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|                 fracpart_len = 0
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|             if random.choice([True, False]):
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|                 s += random.choice(['e', 'E'])
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|                 s += random.choice(signs)
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|                 exponent_len = random.randrange(1, 4)
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|                 s += ''.join(random.choice(digits)
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|                              for _ in range(exponent_len))
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| 
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|             if intpart_len + fracpart_len:
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|                 yield s
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| 
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| test_particular = [
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|      # squares
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|     '1.00000000100000000025',
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|     '1.0000000000000000000000000100000000000000000000000' #...
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|     '00025',
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|     '1.0000000000000000000000000000000000000000000010000' #...
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|     '0000000000000000000000000000000000000000025',
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|     '1.0000000000000000000000000000000000000000000000000' #...
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|     '000001000000000000000000000000000000000000000000000' #...
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|     '000000000025',
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|     '0.99999999900000000025',
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|     '0.9999999999999999999999999999999999999999999999999' #...
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|     '999000000000000000000000000000000000000000000000000' #...
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|     '000025',
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|     '0.9999999999999999999999999999999999999999999999999' #...
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|     '999999999999999999999999999999999999999999999999999' #...
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|     '999999999999999999999999999999999999999990000000000' #...
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|     '000000000000000000000000000000000000000000000000000' #...
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|     '000000000000000000000000000000000000000000000000000' #...
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|     '0000000000000000000000000000025',
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| 
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|     '1.0000000000000000000000000000000000000000000000000' #...
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|     '000000000000000000000000000000000000000000000000000' #...
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|     '100000000000000000000000000000000000000000000000000' #...
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|     '000000000000000000000000000000000000000000000000001',
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|     '1.0000000000000000000000000000000000000000000000000' #...
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|     '000000000000000000000000000000000000000000000000000' #...
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|     '500000000000000000000000000000000000000000000000000' #...
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|     '000000000000000000000000000000000000000000000000005',
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|     '1.0000000000000000000000000000000000000000000000000' #...
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|     '000000000100000000000000000000000000000000000000000' #...
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|     '000000000000000000250000000000000002000000000000000' #...
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|     '000000000000000000000000000000000000000000010000000' #...
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|     '000000000000000000000000000000000000000000000000000' #...
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|     '0000000000000000001',
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|     '1.0000000000000000000000000000000000000000000000000' #...
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|     '000000000100000000000000000000000000000000000000000' #...
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|     '000000000000000000249999999999999999999999999999999' #...
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|     '999999999999979999999999999999999999999999999999999' #...
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|     '999999999999999999999900000000000000000000000000000' #...
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|     '000000000000000000000000000000000000000000000000000' #...
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|     '00000000000000000000000001',
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| 
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|     '0.9999999999999999999999999999999999999999999999999' #...
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|     '999999999900000000000000000000000000000000000000000' #...
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|     '000000000000000000249999999999999998000000000000000' #...
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|     '000000000000000000000000000000000000000000010000000' #...
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|     '000000000000000000000000000000000000000000000000000' #...
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|     '0000000000000000001',
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|     '0.9999999999999999999999999999999999999999999999999' #...
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|     '999999999900000000000000000000000000000000000000000' #...
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|     '000000000000000000250000001999999999999999999999999' #...
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|     '999999999999999999999999999999999990000000000000000' #...
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|     '000000000000000000000000000000000000000000000000000' #...
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|     '1',
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| 
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|     # tough cases for ln etc.
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|     '1.000000000000000000000000000000000000000000000000' #...
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|     '00000000000000000000000000000000000000000000000000' #...
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|     '00100000000000000000000000000000000000000000000000' #...
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|     '00000000000000000000000000000000000000000000000000' #...
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|     '0001',
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|     '0.999999999999999999999999999999999999999999999999' #...
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|     '99999999999999999999999999999999999999999999999999' #...
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|     '99899999999999999999999999999999999999999999999999' #...
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|     '99999999999999999999999999999999999999999999999999' #...
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|     '99999999999999999999999999999999999999999999999999' #...
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|     '9999'
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|     ]
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| 
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| 
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| TESTCASES = [
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|       [x for x in test_short_halfway_cases()],
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|       [x for x in test_halfway_cases()],
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|       [x for x in test_boundaries()],
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|       [x for x in test_underflow_boundary()],
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|       [x for x in test_bigcomp()],
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|       [x for x in test_parsing()],
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|       test_particular
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| ]
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| 
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| def un_randfloat():
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|     for i in range(1000):
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|         l = random.choice(TESTCASES[:6])
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|         yield random.choice(l)
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|     for v in test_particular:
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|         yield v
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| 
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| def bin_randfloat():
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|     for i in range(1000):
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|         l1 = random.choice(TESTCASES)
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|         l2 = random.choice(TESTCASES)
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|         yield random.choice(l1), random.choice(l2)
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| 
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| def tern_randfloat():
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|     for i in range(1000):
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|         l1 = random.choice(TESTCASES)
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|         l2 = random.choice(TESTCASES)
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|         l3 = random.choice(TESTCASES)
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|         yield random.choice(l1), random.choice(l2), random.choice(l3)
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