Lib/test/test_math.py

   1 # Python test set -- math module
   2 # XXXX Should not do tests around zero only
   3
   4 from test.test_support import TestFailed, verbose
   5
   6 seps='1e-05'
   7 eps = eval(seps)
   8 print 'math module, testing with eps', seps
   9 import math
  10
  11 def testit(name, value, expected):
  12     if abs(value-expected) > eps:
  13         raise TestFailed, '%s returned %f, expected %f'%\
  14               (name, value, expected)
  15
  16 print 'constants'
  17 testit('pi', math.pi, 3.1415926)
  18 testit('e', math.e, 2.7182818)
  19
  20 print 'acos'
  21 testit('acos(-1)', math.acos(-1), math.pi)
  22 testit('acos(0)', math.acos(0), math.pi/2)
  23 testit('acos(1)', math.acos(1), 0)
  24
  25 print 'asin'
  26 testit('asin(-1)', math.asin(-1), -math.pi/2)
  27 testit('asin(0)', math.asin(0), 0)
  28 testit('asin(1)', math.asin(1), math.pi/2)
  29
  30 print 'atan'
  31 testit('atan(-1)', math.atan(-1), -math.pi/4)
  32 testit('atan(0)', math.atan(0), 0)
  33 testit('atan(1)', math.atan(1), math.pi/4)
  34
  35 print 'atan2'
  36 testit('atan2(-1, 0)', math.atan2(-1, 0), -math.pi/2)
  37 testit('atan2(-1, 1)', math.atan2(-1, 1), -math.pi/4)
  38 testit('atan2(0, 1)', math.atan2(0, 1), 0)
  39 testit('atan2(1, 1)', math.atan2(1, 1), math.pi/4)
  40 testit('atan2(1, 0)', math.atan2(1, 0), math.pi/2)
  41
  42 print 'ceil'
  43 testit('ceil(0.5)', math.ceil(0.5), 1)
  44 testit('ceil(1.0)', math.ceil(1.0), 1)
  45 testit('ceil(1.5)', math.ceil(1.5), 2)
  46 testit('ceil(-0.5)', math.ceil(-0.5), 0)
  47 testit('ceil(-1.0)', math.ceil(-1.0), -1)
  48 testit('ceil(-1.5)', math.ceil(-1.5), -1)
  49
  50 print 'cos'
  51 testit('cos(-pi/2)', math.cos(-math.pi/2), 0)
  52 testit('cos(0)', math.cos(0), 1)
  53 testit('cos(pi/2)', math.cos(math.pi/2), 0)
  54 testit('cos(pi)', math.cos(math.pi), -1)
  55
  56 print 'cosh'
  57 testit('cosh(0)', math.cosh(0), 1)
  58 testit('cosh(2)-2*cosh(1)**2', math.cosh(2)-2*math.cosh(1)**2, -1) # Thanks to Lambert
  59
  60 print 'degrees'
  61 testit('degrees(pi)', math.degrees(math.pi), 180.0)
  62 testit('degrees(pi/2)', math.degrees(math.pi/2), 90.0)
  63 testit('degrees(-pi/4)', math.degrees(-math.pi/4), -45.0)
  64
  65 print 'exp'
  66 testit('exp(-1)', math.exp(-1), 1/math.e)
  67 testit('exp(0)', math.exp(0), 1)
  68 testit('exp(1)', math.exp(1), math.e)
  69
  70 print 'fabs'
  71 testit('fabs(-1)', math.fabs(-1), 1)
  72 testit('fabs(0)', math.fabs(0), 0)
  73 testit('fabs(1)', math.fabs(1), 1)
  74
  75 print 'floor'
  76 testit('floor(0.5)', math.floor(0.5), 0)
  77 testit('floor(1.0)', math.floor(1.0), 1)
  78 testit('floor(1.5)', math.floor(1.5), 1)
  79 testit('floor(-0.5)', math.floor(-0.5), -1)
  80 testit('floor(-1.0)', math.floor(-1.0), -1)
  81 testit('floor(-1.5)', math.floor(-1.5), -2)
  82
  83 print 'fmod'
  84 testit('fmod(10,1)', math.fmod(10,1), 0)
  85 testit('fmod(10,0.5)', math.fmod(10,0.5), 0)
  86 testit('fmod(10,1.5)', math.fmod(10,1.5), 1)
  87 testit('fmod(-10,1)', math.fmod(-10,1), 0)
  88 testit('fmod(-10,0.5)', math.fmod(-10,0.5), 0)
  89 testit('fmod(-10,1.5)', math.fmod(-10,1.5), -1)
  90
  91 print 'frexp'
  92 def testfrexp(name, (mant, exp), (emant, eexp)):
  93     if abs(mant-emant) > eps or exp != eexp:
  94         raise TestFailed, '%s returned %r, expected %r'%\
  95               (name, (mant, exp), (emant,eexp))
  96
  97 testfrexp('frexp(-1)', math.frexp(-1), (-0.5, 1))
  98 testfrexp('frexp(0)', math.frexp(0), (0, 0))
  99 testfrexp('frexp(1)', math.frexp(1), (0.5, 1))
 100 testfrexp('frexp(2)', math.frexp(2), (0.5, 2))
 101
 102 print 'hypot'
 103 testit('hypot(0,0)', math.hypot(0,0), 0)
 104 testit('hypot(3,4)', math.hypot(3,4), 5)
 105
 106 print 'ldexp'
 107 testit('ldexp(0,1)', math.ldexp(0,1), 0)
 108 testit('ldexp(1,1)', math.ldexp(1,1), 2)
 109 testit('ldexp(1,-1)', math.ldexp(1,-1), 0.5)
 110 testit('ldexp(-1,1)', math.ldexp(-1,1), -2)
 111
 112 print 'log'
 113 testit('log(1/e)', math.log(1/math.e), -1)
 114 testit('log(1)', math.log(1), 0)
 115 testit('log(e)', math.log(math.e), 1)
 116 testit('log(32,2)', math.log(32,2), 5)
 117 testit('log(10**40, 10)', math.log(10**40, 10), 40)
 118 testit('log(10**40, 10**20)', math.log(10**40, 10**20), 2)
 119
 120 print 'log10'
 121 testit('log10(0.1)', math.log10(0.1), -1)
 122 testit('log10(1)', math.log10(1), 0)
 123 testit('log10(10)', math.log10(10), 1)
 124
 125 print 'modf'
 126 def testmodf(name, (v1, v2), (e1, e2)):
 127     if abs(v1-e1) > eps or abs(v2-e2):
 128         raise TestFailed, '%s returned %r, expected %r'%\
 129               (name, (v1,v2), (e1,e2))
 130
 131 testmodf('modf(1.5)', math.modf(1.5), (0.5, 1.0))
 132 testmodf('modf(-1.5)', math.modf(-1.5), (-0.5, -1.0))
 133
 134 print 'pow'
 135 testit('pow(0,1)', math.pow(0,1), 0)
 136 testit('pow(1,0)', math.pow(1,0), 1)
 137 testit('pow(2,1)', math.pow(2,1), 2)
 138 testit('pow(2,-1)', math.pow(2,-1), 0.5)
 139
 140 print 'radians'
 141 testit('radians(180)', math.radians(180), math.pi)
 142 testit('radians(90)', math.radians(90), math.pi/2)
 143 testit('radians(-45)', math.radians(-45), -math.pi/4)
 144
 145 print 'sin'
 146 testit('sin(0)', math.sin(0), 0)
 147 testit('sin(pi/2)', math.sin(math.pi/2), 1)
 148 testit('sin(-pi/2)', math.sin(-math.pi/2), -1)
 149
 150 print 'sinh'
 151 testit('sinh(0)', math.sinh(0), 0)
 152 testit('sinh(1)**2-cosh(1)**2', math.sinh(1)**2-math.cosh(1)**2, -1)
 153 testit('sinh(1)+sinh(-1)', math.sinh(1)+math.sinh(-1), 0)
 154
 155 print 'sqrt'
 156 testit('sqrt(0)', math.sqrt(0), 0)
 157 testit('sqrt(1)', math.sqrt(1), 1)
 158 testit('sqrt(4)', math.sqrt(4), 2)
 159
 160 print 'tan'
 161 testit('tan(0)', math.tan(0), 0)
 162 testit('tan(pi/4)', math.tan(math.pi/4), 1)
 163 testit('tan(-pi/4)', math.tan(-math.pi/4), -1)
 164
 165 print 'tanh'
 166 testit('tanh(0)', math.tanh(0), 0)
 167 testit('tanh(1)+tanh(-1)', math.tanh(1)+math.tanh(-1), 0)
 168
 169 # RED_FLAG 16-Oct-2000 Tim
 170 # While 2.0 is more consistent about exceptions than previous releases, it
 171 # still fails this part of the test on some platforms.  For now, we only
 172 # *run* test_exceptions() in verbose mode, so that this isn't normally
 173 # tested.
 174
 175 def test_exceptions():
 176     print 'exceptions'
 177     try:
 178         x = math.exp(-1000000000)
 179     except:
 180         # mathmodule.c is failing to weed out underflows from libm, or
 181         # we've got an fp format with huge dynamic range
 182         raise TestFailed("underflowing exp() should not have raised "
 183                          "an exception")
 184     if x != 0:
 185         raise TestFailed("underflowing exp() should have returned 0")
 186
 187     # If this fails, probably using a strict IEEE-754 conforming libm, and x
 188     # is +Inf afterwards.  But Python wants overflows detected by default.
 189     try:
 190         x = math.exp(1000000000)
 191     except OverflowError:
 192         pass
 193     else:
 194         raise TestFailed("overflowing exp() didn't trigger OverflowError")
 195
 196     # If this fails, it could be a puzzle.  One odd possibility is that
 197     # mathmodule.c's macros are getting confused while comparing
 198     # Inf (HUGE_VAL) to a NaN, and artificially setting errno to ERANGE
 199     # as a result (and so raising OverflowError instead).
 200     try:
 201         x = math.sqrt(-1.0)
 202     except ValueError:
 203         pass
 204     else:
 205         raise TestFailed("sqrt(-1) didn't raise ValueError")
 206
 207 if verbose:
 208     test_exceptions()