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bpo-38639: Optimize floor(), ceil() and trunc() for floats. #16991

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merged 3 commits into from
Nov 16, 2019
Merged

bpo-38639: Optimize floor(), ceil() and trunc() for floats. #16991

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d80f7bd
bpo-38639: Optimize floor(), ceil() and trunc() for floats.
serhiy-storchaka Oct 30, 2019
265271a
Get rid of math_1_to_int.
serhiy-storchaka Oct 30, 2019
864845a
Add tests.
serhiy-storchaka Nov 7, 2019
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61 changes: 40 additions & 21 deletions Lib/test/test_math.py
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Original file line number Diff line number Diff line change
Expand Up @@ -240,6 +240,13 @@ def result_check(expected, got, ulp_tol=5, abs_tol=0.0):
else:
return None

class FloatLike:
def __init__(self, value):
self.value = value

def __float__(self):
return self.value

class IntSubclass(int):
pass

Expand Down Expand Up @@ -397,22 +404,29 @@ def testAtan2(self):
def testCeil(self):
self.assertRaises(TypeError, math.ceil)
self.assertEqual(int, type(math.ceil(0.5)))
self.ftest('ceil(0.5)', math.ceil(0.5), 1)
self.ftest('ceil(1.0)', math.ceil(1.0), 1)
self.ftest('ceil(1.5)', math.ceil(1.5), 2)
self.ftest('ceil(-0.5)', math.ceil(-0.5), 0)
self.ftest('ceil(-1.0)', math.ceil(-1.0), -1)
self.ftest('ceil(-1.5)', math.ceil(-1.5), -1)
self.assertEqual(math.ceil(0.5), 1)
self.assertEqual(math.ceil(1.0), 1)
self.assertEqual(math.ceil(1.5), 2)
self.assertEqual(math.ceil(-0.5), 0)
self.assertEqual(math.ceil(-1.0), -1)
self.assertEqual(math.ceil(-1.5), -1)
self.assertEqual(math.ceil(0.0), 0)
self.assertEqual(math.ceil(-0.0), 0)
#self.assertEqual(math.ceil(INF), INF)
#self.assertEqual(math.ceil(NINF), NINF)
#self.assertTrue(math.isnan(math.ceil(NAN)))

class TestCeil:
def __ceil__(self):
return 42
class FloatCeil(float):
def __ceil__(self):
return 42
class TestNoCeil:
pass
self.ftest('ceil(TestCeil())', math.ceil(TestCeil()), 42)
self.assertEqual(math.ceil(TestCeil()), 42)
self.assertEqual(math.ceil(FloatCeil()), 42)
self.assertEqual(math.ceil(FloatLike(42.5)), 43)
self.assertRaises(TypeError, math.ceil, TestNoCeil())

t = TestNoCeil()
Expand Down Expand Up @@ -536,26 +550,27 @@ def testFactorialHugeInputs(self):
def testFloor(self):
self.assertRaises(TypeError, math.floor)
self.assertEqual(int, type(math.floor(0.5)))
self.ftest('floor(0.5)', math.floor(0.5), 0)
self.ftest('floor(1.0)', math.floor(1.0), 1)
self.ftest('floor(1.5)', math.floor(1.5), 1)
self.ftest('floor(-0.5)', math.floor(-0.5), -1)
self.ftest('floor(-1.0)', math.floor(-1.0), -1)
self.ftest('floor(-1.5)', math.floor(-1.5), -2)
# pow() relies on floor() to check for integers
# This fails on some platforms - so check it here
self.ftest('floor(1.23e167)', math.floor(1.23e167), 1.23e167)
self.ftest('floor(-1.23e167)', math.floor(-1.23e167), -1.23e167)
self.assertEqual(math.floor(0.5), 0)
self.assertEqual(math.floor(1.0), 1)
self.assertEqual(math.floor(1.5), 1)
self.assertEqual(math.floor(-0.5), -1)
self.assertEqual(math.floor(-1.0), -1)
self.assertEqual(math.floor(-1.5), -2)
#self.assertEqual(math.ceil(INF), INF)
#self.assertEqual(math.ceil(NINF), NINF)
#self.assertTrue(math.isnan(math.floor(NAN)))

class TestFloor:
def __floor__(self):
return 42
class FloatFloor(float):
def __floor__(self):
return 42
class TestNoFloor:
pass
self.ftest('floor(TestFloor())', math.floor(TestFloor()), 42)
self.assertEqual(math.floor(TestFloor()), 42)
self.assertEqual(math.floor(FloatFloor()), 42)
self.assertEqual(math.floor(FloatLike(41.9)), 41)
self.assertRaises(TypeError, math.floor, TestNoFloor())

t = TestNoFloor()
Expand Down Expand Up @@ -1448,17 +1463,21 @@ def test_trunc(self):
self.assertEqual(math.trunc(-0.999999), -0)
self.assertEqual(math.trunc(-100.999), -100)

class TestTrunc(object):
class TestTrunc:
def __trunc__(self):
return 23

class TestNoTrunc(object):
class FloatTrunc(float):
def __trunc__(self):
return 23
class TestNoTrunc:
pass

self.assertEqual(math.trunc(TestTrunc()), 23)
self.assertEqual(math.trunc(FloatTrunc()), 23)

self.assertRaises(TypeError, math.trunc)
self.assertRaises(TypeError, math.trunc, 1, 2)
self.assertRaises(TypeError, math.trunc, FloatLike(23.5))
self.assertRaises(TypeError, math.trunc, TestNoTrunc())

def testIsfinite(self):
Expand Down
2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/Core and Builtins/2019-10-30-11-31-47.bpo-38639.9-vKtO.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
Optimized :func:`math.floor()`, :func:`math.ceil()` and :func:`math.trunc()`
for floats.
48 changes: 28 additions & 20 deletions Modules/mathmodule.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1013,12 +1013,6 @@ math_1(PyObject *arg, double (*func) (double), int can_overflow)
return math_1_to_whatever(arg, func, PyFloat_FromDouble, can_overflow);
}

static PyObject *
math_1_to_int(PyObject *arg, double (*func) (double), int can_overflow)
{
return math_1_to_whatever(arg, func, PyLong_FromDouble, can_overflow);
}

static PyObject *
math_2(PyObject *const *args, Py_ssize_t nargs,
double (*func) (double, double), const char *funcname)
Expand Down Expand Up @@ -1112,17 +1106,22 @@ math_ceil(PyObject *module, PyObject *number)
/*[clinic end generated code: output=6c3b8a78bc201c67 input=2725352806399cab]*/
{
_Py_IDENTIFIER(__ceil__);
PyObject *method, *result;

method = _PyObject_LookupSpecial(number, &PyId___ceil__);
if (method == NULL) {
if (!PyFloat_CheckExact(number)) {
PyObject *method = _PyObject_LookupSpecial(number, &PyId___ceil__);
if (method != NULL) {
PyObject *result = _PyObject_CallNoArg(method);
Py_DECREF(method);
return result;
}
if (PyErr_Occurred())
return NULL;
return math_1_to_int(number, ceil, 0);
}
result = _PyObject_CallNoArg(method);
Py_DECREF(method);
return result;
double x = PyFloat_AsDouble(number);
if (x == -1.0 && PyErr_Occurred())
return NULL;

return PyLong_FromDouble(ceil(x));
}

FUNC2(copysign, copysign,
Expand Down Expand Up @@ -1170,17 +1169,22 @@ math_floor(PyObject *module, PyObject *number)
/*[clinic end generated code: output=c6a65c4884884b8a input=63af6b5d7ebcc3d6]*/
{
_Py_IDENTIFIER(__floor__);
PyObject *method, *result;

method = _PyObject_LookupSpecial(number, &PyId___floor__);
if (method == NULL) {
if (!PyFloat_CheckExact(number)) {
PyObject *method = _PyObject_LookupSpecial(number, &PyId___floor__);
if (method != NULL) {
PyObject *result = _PyObject_CallNoArg(method);
Py_DECREF(method);
return result;
}
if (PyErr_Occurred())
return NULL;
return math_1_to_int(number, floor, 0);
}
result = _PyObject_CallNoArg(method);
Py_DECREF(method);
return result;
double x = PyFloat_AsDouble(number);
if (x == -1.0 && PyErr_Occurred())
return NULL;

return PyLong_FromDouble(floor(x));
}

FUNC1A(gamma, m_tgamma,
Expand Down Expand Up @@ -2061,6 +2065,10 @@ math_trunc(PyObject *module, PyObject *x)
_Py_IDENTIFIER(__trunc__);
PyObject *trunc, *result;

if (PyFloat_CheckExact(x)) {
return PyFloat_Type.tp_as_number->nb_int(x);
}

if (Py_TYPE(x)->tp_dict == NULL) {
if (PyType_Ready(Py_TYPE(x)) < 0)
return NULL;
Expand Down