cpython/Lib/test/test_math.py
Tim Peters a40c793d06 Rework the way we try to check for libm overflow, given that C99 no longer
requires that errno ever get set, and it looks like glibc is already
playing that game.  New rules:

+ Never use HUGE_VAL.  Use the new Py_HUGE_VAL instead.

+ Never believe errno.  If overflow is the only thing you're interested in,
  use the new Py_OVERFLOWED(x) macro.  If you're interested in any libm
  errors, use the new Py_SET_ERANGE_IF_OVERFLOW(x) macro, which attempts
  to set errno the way C89 said it worked.

Unfortunately, none of these are reliable, but they work on Windows and I
*expect* under glibc too.
2001-09-05 22:36:56 +00:00

196 lines
5.9 KiB
Python

# Python test set -- math module
# XXXX Should not do tests around zero only
from test_support import *
seps='1e-05'
eps = eval(seps)
print 'math module, testing with eps', seps
import math
def testit(name, value, expected):
if abs(value-expected) > eps:
raise TestFailed, '%s returned %f, expected %f'%\
(name, value, expected)
print 'constants'
testit('pi', math.pi, 3.1415926)
testit('e', math.e, 2.7182818)
print 'acos'
testit('acos(-1)', math.acos(-1), math.pi)
testit('acos(0)', math.acos(0), math.pi/2)
testit('acos(1)', math.acos(1), 0)
print 'asin'
testit('asin(-1)', math.asin(-1), -math.pi/2)
testit('asin(0)', math.asin(0), 0)
testit('asin(1)', math.asin(1), math.pi/2)
print 'atan'
testit('atan(-1)', math.atan(-1), -math.pi/4)
testit('atan(0)', math.atan(0), 0)
testit('atan(1)', math.atan(1), math.pi/4)
print 'atan2'
testit('atan2(-1, 0)', math.atan2(-1, 0), -math.pi/2)
testit('atan2(-1, 1)', math.atan2(-1, 1), -math.pi/4)
testit('atan2(0, 1)', math.atan2(0, 1), 0)
testit('atan2(1, 1)', math.atan2(1, 1), math.pi/4)
testit('atan2(1, 0)', math.atan2(1, 0), math.pi/2)
print 'ceil'
testit('ceil(0.5)', math.ceil(0.5), 1)
testit('ceil(1.0)', math.ceil(1.0), 1)
testit('ceil(1.5)', math.ceil(1.5), 2)
testit('ceil(-0.5)', math.ceil(-0.5), 0)
testit('ceil(-1.0)', math.ceil(-1.0), -1)
testit('ceil(-1.5)', math.ceil(-1.5), -1)
print 'cos'
testit('cos(-pi/2)', math.cos(-math.pi/2), 0)
testit('cos(0)', math.cos(0), 1)
testit('cos(pi/2)', math.cos(math.pi/2), 0)
testit('cos(pi)', math.cos(math.pi), -1)
print 'cosh'
testit('cosh(0)', math.cosh(0), 1)
testit('cosh(2)-2*cosh(1)**2', math.cosh(2)-2*math.cosh(1)**2, -1) # Thanks to Lambert
print 'exp'
testit('exp(-1)', math.exp(-1), 1/math.e)
testit('exp(0)', math.exp(0), 1)
testit('exp(1)', math.exp(1), math.e)
print 'fabs'
testit('fabs(-1)', math.fabs(-1), 1)
testit('fabs(0)', math.fabs(0), 0)
testit('fabs(1)', math.fabs(1), 1)
print 'floor'
testit('floor(0.5)', math.floor(0.5), 0)
testit('floor(1.0)', math.floor(1.0), 1)
testit('floor(1.5)', math.floor(1.5), 1)
testit('floor(-0.5)', math.floor(-0.5), -1)
testit('floor(-1.0)', math.floor(-1.0), -1)
testit('floor(-1.5)', math.floor(-1.5), -2)
print 'fmod'
testit('fmod(10,1)', math.fmod(10,1), 0)
testit('fmod(10,0.5)', math.fmod(10,0.5), 0)
testit('fmod(10,1.5)', math.fmod(10,1.5), 1)
testit('fmod(-10,1)', math.fmod(-10,1), 0)
testit('fmod(-10,0.5)', math.fmod(-10,0.5), 0)
testit('fmod(-10,1.5)', math.fmod(-10,1.5), -1)
print 'frexp'
def testfrexp(name, (mant, exp), (emant, eexp)):
if abs(mant-emant) > eps or exp != eexp:
raise TestFailed, '%s returned %s, expected %s'%\
(name, `mant, exp`, `emant,eexp`)
testfrexp('frexp(-1)', math.frexp(-1), (-0.5, 1))
testfrexp('frexp(0)', math.frexp(0), (0, 0))
testfrexp('frexp(1)', math.frexp(1), (0.5, 1))
testfrexp('frexp(2)', math.frexp(2), (0.5, 2))
print 'hypot'
testit('hypot(0,0)', math.hypot(0,0), 0)
testit('hypot(3,4)', math.hypot(3,4), 5)
print 'ldexp'
testit('ldexp(0,1)', math.ldexp(0,1), 0)
testit('ldexp(1,1)', math.ldexp(1,1), 2)
testit('ldexp(1,-1)', math.ldexp(1,-1), 0.5)
testit('ldexp(-1,1)', math.ldexp(-1,1), -2)
print 'log'
testit('log(1/e)', math.log(1/math.e), -1)
testit('log(1)', math.log(1), 0)
testit('log(e)', math.log(math.e), 1)
print 'log10'
testit('log10(0.1)', math.log10(0.1), -1)
testit('log10(1)', math.log10(1), 0)
testit('log10(10)', math.log10(10), 1)
print 'modf'
def testmodf(name, (v1, v2), (e1, e2)):
if abs(v1-e1) > eps or abs(v2-e2):
raise TestFailed, '%s returned %s, expected %s'%\
(name, `v1,v2`, `e1,e2`)
testmodf('modf(1.5)', math.modf(1.5), (0.5, 1.0))
testmodf('modf(-1.5)', math.modf(-1.5), (-0.5, -1.0))
print 'pow'
testit('pow(0,1)', math.pow(0,1), 0)
testit('pow(1,0)', math.pow(1,0), 1)
testit('pow(2,1)', math.pow(2,1), 2)
testit('pow(2,-1)', math.pow(2,-1), 0.5)
print 'sin'
testit('sin(0)', math.sin(0), 0)
testit('sin(pi/2)', math.sin(math.pi/2), 1)
testit('sin(-pi/2)', math.sin(-math.pi/2), -1)
print 'sinh'
testit('sinh(0)', math.sinh(0), 0)
testit('sinh(1)**2-cosh(1)**2', math.sinh(1)**2-math.cosh(1)**2, -1)
testit('sinh(1)+sinh(-1)', math.sinh(1)+math.sinh(-1), 0)
print 'sqrt'
testit('sqrt(0)', math.sqrt(0), 0)
testit('sqrt(1)', math.sqrt(1), 1)
testit('sqrt(4)', math.sqrt(4), 2)
print 'tan'
testit('tan(0)', math.tan(0), 0)
testit('tan(pi/4)', math.tan(math.pi/4), 1)
testit('tan(-pi/4)', math.tan(-math.pi/4), -1)
print 'tanh'
testit('tanh(0)', math.tanh(0), 0)
testit('tanh(1)+tanh(-1)', math.tanh(1)+math.tanh(-1), 0)
# RED_FLAG 16-Oct-2000 Tim
# While 2.0 is more consistent about exceptions than previous releases, it
# still fails this part of the test on some platforms. For now, we only
# *run* test_exceptions() in verbose mode, so that this isn't normally
# tested.
def test_exceptions():
print 'exceptions'
try:
x = math.exp(-1000000000)
except:
# mathmodule.c is failing to weed out underflows from libm, or
# we've got an fp format with huge dynamic range
raise TestFailed("underflowing exp() should not have raised "
"an exception")
if x != 0:
raise TestFailed("underflowing exp() should have returned 0")
# If this fails, probably using a strict IEEE-754 conforming libm, and x
# is +Inf afterwards. But Python wants overflows detected by default.
try:
x = math.exp(1000000000)
except OverflowError:
pass
else:
raise TestFailed("overflowing exp() didn't trigger OverflowError")
# If this fails, it could be a puzzle. One odd possibility is that
# mathmodule.c's macros are getting confused while comparing
# Inf (HUGE_VAL) to a NaN, and artificially setting errno to ERANGE
# as a result (and so raising OverflowError instead).
try:
x = math.sqrt(-1.0)
except ValueError:
pass
else:
raise TestFailed("sqrt(-1) didn't raise ValueError")
if verbose:
test_exceptions()