mirror of https://github.com/python/cpython.git
66 lines
1.8 KiB
Python
66 lines
1.8 KiB
Python
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from test_support import TestFailed
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from random import random
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# XXX need many, many more tests here.
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nerrors = 0
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def check_close_real(x, y, eps=1e-12):
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"""Return true iff floats x and y "are close\""""
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# put the one with larger magnitude second
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if abs(x) > abs(y):
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x, y = y, x
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if y == 0:
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return abs(x) < eps
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if x == 0:
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return abs(y) < eps
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# check that relative difference < eps
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return abs((x-y)/y) < eps
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def check_close(x, y, eps=1e-12):
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"""Return true iff complexes x and y "are close\""""
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return check_close_real(x.real, y.real, eps) and \
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check_close_real(x.imag, y.imag, eps)
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def test_div(x, y):
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"""Compute complex z=x*y, and check that z/x==y and z/y==x."""
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global nerrors
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z = x * y
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if x != 0:
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q = z / x
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if not check_close(q, y):
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nerrors += 1
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print `z`, "/", `x`, "==", `q`, "but expected", `y`
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if y != 0:
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q = z / y
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if not check_close(q, x):
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nerrors += 1
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print `z`, "/", `y`, "==", `q`, "but expected", `x`
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simple_real = [float(i) for i in range(-5, 6)]
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simple_complex = [complex(x, y) for x in simple_real for y in simple_real]
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for x in simple_complex:
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for y in simple_complex:
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test_div(x, y)
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# A naive complex division algorithm (such as in 2.0) is very prone to
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# nonsense errors for these (overflows and underflows).
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test_div(complex(1e200, 1e200), 1+0j)
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test_div(complex(1e-200, 1e-200), 1+0j)
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# Just for fun.
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for i in range(100):
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test_div(complex(random(), random()),
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complex(random(), random()))
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try:
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z = 1.0 / (0+0j)
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except ZeroDivisionError:
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pass
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else:
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nerrors += 1
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raise TestFailed("Division by complex 0 didn't raise ZeroDivisionError")
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if nerrors:
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raise TestFailed("%d tests failed" % nerrors)
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