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 %s, expected %s'%\
  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
 117 print 'log10'
 118 testit('log10(0.1)', math.log10(0.1), -1)
 119 testit('log10(1)', math.log10(1), 0)
 120 testit('log10(10)', math.log10(10), 1)
 121
 122 print 'modf'
 123 def testmodf(name, (v1, v2), (e1, e2)):
 124     if abs(v1-e1) > eps or abs(v2-e2):
 125         raise TestFailed, '%s returned %s, expected %s'%\
 126               (name, `v1,v2`, `e1,e2`)
 127
 128 testmodf('modf(1.5)', math.modf(1.5), (0.5, 1.0))
 129 testmodf('modf(-1.5)', math.modf(-1.5), (-0.5, -1.0))
 130
 131 print 'pow'
 132 testit('pow(0,1)', math.pow(0,1), 0)
 133 testit('pow(1,0)', math.pow(1,0), 1)
 134 testit('pow(2,1)', math.pow(2,1), 2)
 135 testit('pow(2,-1)', math.pow(2,-1), 0.5)
 136
 137 print 'radians'
 138 testit('radians(180)', math.radians(180), math.pi)
 139 testit('radians(90)', math.radians(90), math.pi/2)
 140 testit('radians(-45)', math.radians(-45), -math.pi/4)
 141
 142 print 'sin'
 143 testit('sin(0)', math.sin(0), 0)
 144 testit('sin(pi/2)', math.sin(math.pi/2), 1)
 145 testit('sin(-pi/2)', math.sin(-math.pi/2), -1)
 146
 147 print 'sinh'
 148 testit('sinh(0)', math.sinh(0), 0)
 149 testit('sinh(1)**2-cosh(1)**2', math.sinh(1)**2-math.cosh(1)**2, -1)
 150 testit('sinh(1)+sinh(-1)', math.sinh(1)+math.sinh(-1), 0)
 151
 152 print 'sqrt'
 153 testit('sqrt(0)', math.sqrt(0), 0)
 154 testit('sqrt(1)', math.sqrt(1), 1)
 155 testit('sqrt(4)', math.sqrt(4), 2)
 156
 157 print 'tan'
 158 testit('tan(0)', math.tan(0), 0)
 159 testit('tan(pi/4)', math.tan(math.pi/4), 1)
 160 testit('tan(-pi/4)', math.tan(-math.pi/4), -1)
 161
 162 print 'tanh'
 163 testit('tanh(0)', math.tanh(0), 0)
 164 testit('tanh(1)+tanh(-1)', math.tanh(1)+math.tanh(-1), 0)
 165
 166 # RED_FLAG 16-Oct-2000 Tim
 167 # While 2.0 is more consistent about exceptions than previous releases, it
 168 # still fails this part of the test on some platforms.  For now, we only
 169 # *run* test_exceptions() in verbose mode, so that this isn't normally
 170 # tested.
 171
 172 def test_exceptions():
 173     print 'exceptions'
 174     try:
 175         x = math.exp(-1000000000)
 176     except:
 177         # mathmodule.c is failing to weed out underflows from libm, or
 178         # we've got an fp format with huge dynamic range
 179         raise TestFailed("underflowing exp() should not have raised "
 180                          "an exception")
 181     if x != 0:
 182         raise TestFailed("underflowing exp() should have returned 0")
 183
 184     # If this fails, probably using a strict IEEE-754 conforming libm, and x
 185     # is +Inf afterwards.  But Python wants overflows detected by default.
 186     try:
 187         x = math.exp(1000000000)
 188     except OverflowError:
 189         pass
 190     else:
 191         raise TestFailed("overflowing exp() didn't trigger OverflowError")
 192
 193     # If this fails, it could be a puzzle.  One odd possibility is that
 194     # mathmodule.c's macros are getting confused while comparing
 195     # Inf (HUGE_VAL) to a NaN, and artificially setting errno to ERANGE
 196     # as a result (and so raising OverflowError instead).
 197     try:
 198         x = math.sqrt(-1.0)
 199     except ValueError:
 200         pass
 201     else:
 202         raise TestFailed("sqrt(-1) didn't raise ValueError")
 203
 204 if verbose:
 205     test_exceptions()