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Additional tests for math.pow, and extra special-case 

handling code in math.pow, in the hope of making all
tests pass on the alpha Tru64 buildbot.
This commit is contained in:
Mark Dickinson 2008-04-19 18:51:48 +00:00
parent c7bef37402
commit e941d97d12
2 changed files with 135 additions and 10 deletions
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134
Lib/test/test_math.py
View File

@ -102,7 +102,7 @@ class MathTests(unittest.TestCase):
self.ftest('atan(0)', math.atan(0), 0) self.ftest('atan(0)', math.atan(0), 0)
self.ftest('atan(1)', math.atan(1), math.pi/4) self.ftest('atan(1)', math.atan(1), math.pi/4)
self.ftest('atan(inf)', math.atan(INF), math.pi/2) self.ftest('atan(inf)', math.atan(INF), math.pi/2)
self.ftest('atan(-inf)', math.atan(-INF), -math.pi/2) self.ftest('atan(-inf)', math.atan(NINF), -math.pi/2)
self.assert_(math.isnan(math.atan(NAN))) self.assert_(math.isnan(math.atan(NAN)))
def testAtanh(self): def testAtanh(self):
@ -387,14 +387,128 @@ class MathTests(unittest.TestCase):
self.assert_(math.isnan(math.pow(2, NAN))) self.assert_(math.isnan(math.pow(2, NAN)))
self.assert_(math.isnan(math.pow(0, NAN))) self.assert_(math.isnan(math.pow(0, NAN)))
self.assertEqual(math.pow(1, NAN), 1) self.assertEqual(math.pow(1, NAN), 1)
self.assertEqual(1**NAN, 1)
self.assertEqual(1**INF, 1) # pow(0., x)
self.assertEqual(1**NINF, 1) self.assertEqual(math.pow(0., INF), 0.)
self.assertEqual(1**0, 1) self.assertEqual(math.pow(0., 3.), 0.)
self.assertEqual(1.**NAN, 1) self.assertEqual(math.pow(0., 2.3), 0.)
self.assertEqual(1.**INF, 1) self.assertEqual(math.pow(0., 2.), 0.)
self.assertEqual(1.**NINF, 1) self.assertEqual(math.pow(0., 0.), 1.)
self.assertEqual(1.**0, 1) self.assertEqual(math.pow(0., -0.), 1.)
self.assertRaises(ValueError, math.pow, 0., -2.)
self.assertRaises(ValueError, math.pow, 0., -2.3)
self.assertRaises(ValueError, math.pow, 0., -3.)
self.assertRaises(ValueError, math.pow, 0., NINF)
self.assert_(math.isnan(math.pow(0., NAN)))
# pow(INF, x)
self.assertEqual(math.pow(INF, INF), INF)
self.assertEqual(math.pow(INF, 3.), INF)
self.assertEqual(math.pow(INF, 2.3), INF)
self.assertEqual(math.pow(INF, 2.), INF)
self.assertEqual(math.pow(INF, 0.), 1.)
self.assertEqual(math.pow(INF, -0.), 1.)
self.assertEqual(math.pow(INF, -2.), 0.)
self.assertEqual(math.pow(INF, -2.3), 0.)
self.assertEqual(math.pow(INF, -3.), 0.)
self.assertEqual(math.pow(INF, NINF), 0.)
self.assert_(math.isnan(math.pow(INF, NAN)))
# pow(-0., x)
self.assertEqual(math.pow(-0., INF), 0.)
self.assertEqual(math.pow(-0., 3.), -0.)
self.assertEqual(math.pow(-0., 2.3), 0.)
self.assertEqual(math.pow(-0., 2.), 0.)
self.assertEqual(math.pow(-0., 0.), 1.)
self.assertEqual(math.pow(-0., -0.), 1.)
self.assertRaises(ValueError, math.pow, -0., -2.)
self.assertRaises(ValueError, math.pow, -0., -2.3)
self.assertRaises(ValueError, math.pow, -0., -3.)
self.assertRaises(ValueError, math.pow, -0., NINF)
self.assert_(math.isnan(math.pow(-0., NAN)))
# pow(NINF, x)
self.assertEqual(math.pow(NINF, INF), INF)
self.assertEqual(math.pow(NINF, 3.), NINF)
self.assertEqual(math.pow(NINF, 2.3), INF)
self.assertEqual(math.pow(NINF, 2.), INF)
self.assertEqual(math.pow(NINF, 0.), 1.)
self.assertEqual(math.pow(NINF, -0.), 1.)
self.assertEqual(math.pow(NINF, -2.), 0.)
self.assertEqual(math.pow(NINF, -2.3), 0.)
self.assertEqual(math.pow(NINF, -3.), -0.)
self.assertEqual(math.pow(NINF, NINF), 0.)
self.assert_(math.isnan(math.pow(NINF, NAN)))
# pow(-1, x)
self.assertEqual(math.pow(-1., INF), 1.)
self.assertEqual(math.pow(-1., 3.), -1.)
self.assertRaises(ValueError, math.pow, -1., 2.3)
self.assertEqual(math.pow(-1., 2.), 1.)
self.assertEqual(math.pow(-1., 0.), 1.)
self.assertEqual(math.pow(-1., -0.), 1.)
self.assertEqual(math.pow(-1., -2.), 1.)
self.assertRaises(ValueError, math.pow, -1., -2.3)
self.assertEqual(math.pow(-1., -3.), -1.)
self.assertEqual(math.pow(-1., NINF), 1.)
self.assert_(math.isnan(math.pow(-1., NAN)))
# pow(1, x)
self.assertEqual(math.pow(1., INF), 1.)
self.assertEqual(math.pow(1., 3.), 1.)
self.assertEqual(math.pow(1., 2.3), 1.)
self.assertEqual(math.pow(1., 2.), 1.)
self.assertEqual(math.pow(1., 0.), 1.)
self.assertEqual(math.pow(1., -0.), 1.)
self.assertEqual(math.pow(1., -2.), 1.)
self.assertEqual(math.pow(1., -2.3), 1.)
self.assertEqual(math.pow(1., -3.), 1.)
self.assertEqual(math.pow(1., NINF), 1.)
self.assertEqual(math.pow(1., NAN), 1.)
# pow(x, 0) should be 1 for any x
self.assertEqual(math.pow(2.3, 0.), 1.)
self.assertEqual(math.pow(-2.3, 0.), 1.)
self.assertEqual(math.pow(NAN, 0.), 1.)
self.assertEqual(math.pow(2.3, -0.), 1.)
self.assertEqual(math.pow(-2.3, -0.), 1.)
self.assertEqual(math.pow(NAN, -0.), 1.)
# pow(x, y) is invalid if x is negative and y is not integral
self.assertRaises(ValueError, math.pow, -1., 2.3)
self.assertRaises(ValueError, math.pow, -15., -3.1)
# pow(x, NINF)
self.assertEqual(math.pow(1.9, NINF), 0.)
self.assertEqual(math.pow(1.1, NINF), 0.)
self.assertEqual(math.pow(0.9, NINF), INF)
self.assertEqual(math.pow(0.1, NINF), INF)
self.assertEqual(math.pow(-0.1, NINF), INF)
self.assertEqual(math.pow(-0.9, NINF), INF)
self.assertEqual(math.pow(-1.1, NINF), 0.)
self.assertEqual(math.pow(-1.9, NINF), 0.)
# pow(x, INF)
self.assertEqual(math.pow(1.9, INF), INF)
self.assertEqual(math.pow(1.1, INF), INF)
self.assertEqual(math.pow(0.9, INF), 0.)
self.assertEqual(math.pow(0.1, INF), 0.)
self.assertEqual(math.pow(-0.1, INF), 0.)
self.assertEqual(math.pow(-0.9, INF), 0.)
self.assertEqual(math.pow(-1.1, INF), INF)
self.assertEqual(math.pow(-1.9, INF), INF)
# the following tests have been commented out since they don't
# really belong here: the implementation of ** for floats is
# independent of the implemention of math.pow
#self.assertEqual(1**NAN, 1)
#self.assertEqual(1**INF, 1)
#self.assertEqual(1**NINF, 1)
#self.assertEqual(1**0, 1)
#self.assertEqual(1.**NAN, 1)
#self.assertEqual(1.**INF, 1)
#self.assertEqual(1.**NINF, 1)
#self.assertEqual(1.**0, 1)
def testRadians(self): def testRadians(self):
self.assertRaises(TypeError, math.radians) self.assertRaises(TypeError, math.radians)
@ -421,7 +535,7 @@ class MathTests(unittest.TestCase):
self.ftest('sinh(1)**2-cosh(1)**2', math.sinh(1)**2-math.cosh(1)**2, -1) self.ftest('sinh(1)**2-cosh(1)**2', math.sinh(1)**2-math.cosh(1)**2, -1)
self.ftest('sinh(1)+sinh(-1)', math.sinh(1)+math.sinh(-1), 0) self.ftest('sinh(1)+sinh(-1)', math.sinh(1)+math.sinh(-1), 0)
self.assertEquals(math.sinh(INF), INF) self.assertEquals(math.sinh(INF), INF)
self.assertEquals(math.sinh(-INF), -INF) self.assertEquals(math.sinh(NINF), NINF)
self.assert_(math.isnan(math.sinh(NAN))) self.assert_(math.isnan(math.sinh(NAN)))
def testSqrt(self): def testSqrt(self):

11
Modules/mathmodule.c
View File

@ -513,6 +513,7 @@ math_pow(PyObject *self, PyObject *args)
{ {
PyObject *ox, *oy; PyObject *ox, *oy;
double r, x, y; double r, x, y;
int y_is_odd;
if (! PyArg_UnpackTuple(args, "pow", 2, 2, &ox, &oy)) if (! PyArg_UnpackTuple(args, "pow", 2, 2, &ox, &oy))
return NULL; return NULL;
@ -523,6 +524,16 @@ math_pow(PyObject *self, PyObject *args)
/* 1**x and x**0 return 1., even if x is a NaN or infinity. */ /* 1**x and x**0 return 1., even if x is a NaN or infinity. */
if (x == 1.0 || y == 0.0) if (x == 1.0 || y == 0.0)
return PyFloat_FromDouble(1.); return PyFloat_FromDouble(1.);
/* inf ** (nonzero, non-NaN) is one of +-0, +-infinity */
if (Py_IS_INFINITY(x) && !Py_IS_NAN(y)) {
y_is_odd = Py_IS_FINITE(y) && fmod(fabs(y), 2.0) == 1.0;
if (y > 0.)
r = y_is_odd ? x : fabs(x);
else
r = y_is_odd ? copysign(0., x) : 0.;
return PyFloat_FromDouble(r);
}
errno = 0; errno = 0;
PyFPE_START_PROTECT("in math_pow", return 0); PyFPE_START_PROTECT("in math_pow", return 0);
r = pow(x, y); r = pow(x, y);