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-rw-r--r--Doc/library/math.rst20
-rw-r--r--Lib/test/test_math.py12
-rw-r--r--Modules/clinic/mathmodule.c.h22
-rw-r--r--Modules/mathmodule.c33
4 files changed, 49 insertions, 38 deletions
diff --git a/Doc/library/math.rst b/Doc/library/math.rst
index c5a77f1..4a15789 100644
--- a/Doc/library/math.rst
+++ b/Doc/library/math.rst
@@ -41,12 +41,15 @@ Number-theoretic and representation functions
Return the number of ways to choose *k* items from *n* items without repetition
and without order.
- Also called the binomial coefficient. It is mathematically equal to the expression
- ``n! / (k! (n - k)!)``. It is equivalent to the coefficient of the *k*-th term in the
- polynomial expansion of the expression ``(1 + x) ** n``.
+ Evaluates to ``n! / (k! * (n - k)!)`` when ``k <= n`` and evaluates
+ to zero when ``k > n``.
- Raises :exc:`TypeError` if the arguments not integers.
- Raises :exc:`ValueError` if the arguments are negative or if *k* > *n*.
+ Also called the binomial coefficient because it is equivalent
+ to the coefficient of k-th term in polynomial expansion of the
+ expression ``(1 + x) ** n``.
+
+ Raises :exc:`TypeError` if either of the arguments not integers.
+ Raises :exc:`ValueError` if either of the arguments are negative.
.. versionadded:: 3.8
@@ -212,10 +215,11 @@ Number-theoretic and representation functions
Return the number of ways to choose *k* items from *n* items
without repetition and with order.
- It is mathematically equal to the expression ``n! / (n - k)!``.
+ Evaluates to ``n! / (n - k)!`` when ``k <= n`` and evaluates
+ to zero when ``k > n``.
- Raises :exc:`TypeError` if the arguments not integers.
- Raises :exc:`ValueError` if the arguments are negative or if *k* > *n*.
+ Raises :exc:`TypeError` if either of the arguments not integers.
+ Raises :exc:`ValueError` if either of the arguments are negative.
.. versionadded:: 3.8
diff --git a/Lib/test/test_math.py b/Lib/test/test_math.py
index 96e0cf2..86e3923 100644
--- a/Lib/test/test_math.py
+++ b/Lib/test/test_math.py
@@ -1904,9 +1904,9 @@ class IsCloseTests(unittest.TestCase):
self.assertRaises(ValueError, perm, 1, -1)
self.assertRaises(ValueError, perm, 1, -2**1000)
- # Raises value error if k is greater than n
- self.assertRaises(ValueError, perm, 1, 2)
- self.assertRaises(ValueError, perm, 1, 2**1000)
+ # Returns zero if k is greater than n
+ self.assertEqual(perm(1, 2), 0)
+ self.assertEqual(perm(1, 2**1000), 0)
n = 2**1000
self.assertEqual(perm(n, 0), 1)
@@ -1970,9 +1970,9 @@ class IsCloseTests(unittest.TestCase):
self.assertRaises(ValueError, comb, 1, -1)
self.assertRaises(ValueError, comb, 1, -2**1000)
- # Raises value error if k is greater than n
- self.assertRaises(ValueError, comb, 1, 2)
- self.assertRaises(ValueError, comb, 1, 2**1000)
+ # Returns zero if k is greater than n
+ self.assertEqual(comb(1, 2), 0)
+ self.assertEqual(comb(1, 2**1000), 0)
n = 2**1000
self.assertEqual(comb(n, 0), 1)
diff --git a/Modules/clinic/mathmodule.c.h b/Modules/clinic/mathmodule.c.h
index 0efe5cc..cdf4305 100644
--- a/Modules/clinic/mathmodule.c.h
+++ b/Modules/clinic/mathmodule.c.h
@@ -644,10 +644,11 @@ PyDoc_STRVAR(math_perm__doc__,
"\n"
"Number of ways to choose k items from n items without repetition and with order.\n"
"\n"
-"It is mathematically equal to the expression n! / (n - k)!.\n"
+"Evaluates to n! / (n - k)! when k <= n and evaluates\n"
+"to zero when k > n.\n"
"\n"
-"Raises TypeError if the arguments are not integers.\n"
-"Raises ValueError if the arguments are negative or if k > n.");
+"Raises TypeError if either of the arguments are not integers.\n"
+"Raises ValueError if either of the arguments are negative.");
#define MATH_PERM_METHODDEF \
{"perm", (PyCFunction)(void(*)(void))math_perm, METH_FASTCALL, math_perm__doc__},
@@ -679,12 +680,15 @@ PyDoc_STRVAR(math_comb__doc__,
"\n"
"Number of ways to choose k items from n items without repetition and without order.\n"
"\n"
-"Also called the binomial coefficient. It is mathematically equal to the expression\n"
-"n! / (k! * (n - k)!). It is equivalent to the coefficient of k-th term in\n"
-"polynomial expansion of the expression (1 + x)**n.\n"
+"Evaluates to n! / (k! * (n - k)!) when k <= n and evaluates\n"
+"to zero when k > n.\n"
"\n"
-"Raises TypeError if the arguments are not integers.\n"
-"Raises ValueError if the arguments are negative or if k > n.");
+"Also called the binomial coefficient because it is equivalent\n"
+"to the coefficient of k-th term in polynomial expansion of the\n"
+"expression (1 + x)**n.\n"
+"\n"
+"Raises TypeError if either of the arguments are not integers.\n"
+"Raises ValueError if either of the arguments are negative.");
#define MATH_COMB_METHODDEF \
{"comb", (PyCFunction)(void(*)(void))math_comb, METH_FASTCALL, math_comb__doc__},
@@ -709,4 +713,4 @@ math_comb(PyObject *module, PyObject *const *args, Py_ssize_t nargs)
exit:
return return_value;
}
-/*[clinic end generated code: output=a82b0e705b6d0ec0 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=5004266613284dcc input=a9049054013a1b77]*/
diff --git a/Modules/mathmodule.c b/Modules/mathmodule.c
index 6e10993..9a9a815 100644
--- a/Modules/mathmodule.c
+++ b/Modules/mathmodule.c
@@ -3007,15 +3007,16 @@ math.perm
Number of ways to choose k items from n items without repetition and with order.
-It is mathematically equal to the expression n! / (n - k)!.
+Evaluates to n! / (n - k)! when k <= n and evaluates
+to zero when k > n.
-Raises TypeError if the arguments are not integers.
-Raises ValueError if the arguments are negative or if k > n.
+Raises TypeError if either of the arguments are not integers.
+Raises ValueError if either of the arguments are negative.
[clinic start generated code]*/
static PyObject *
math_perm_impl(PyObject *module, PyObject *n, PyObject *k)
-/*[clinic end generated code: output=e021a25469653e23 input=f71ee4f6ff26be24]*/
+/*[clinic end generated code: output=e021a25469653e23 input=b2e7729d9a1949cf]*/
{
PyObject *result = NULL, *factor = NULL;
int overflow, cmp;
@@ -3052,8 +3053,8 @@ math_perm_impl(PyObject *module, PyObject *n, PyObject *k)
cmp = PyObject_RichCompareBool(n, k, Py_LT);
if (cmp != 0) {
if (cmp > 0) {
- PyErr_SetString(PyExc_ValueError,
- "k must be an integer less than or equal to n");
+ result = PyLong_FromLong(0);
+ goto done;
}
goto error;
}
@@ -3121,18 +3122,21 @@ math.comb
Number of ways to choose k items from n items without repetition and without order.
-Also called the binomial coefficient. It is mathematically equal to the expression
-n! / (k! * (n - k)!). It is equivalent to the coefficient of k-th term in
-polynomial expansion of the expression (1 + x)**n.
+Evaluates to n! / (k! * (n - k)!) when k <= n and evaluates
+to zero when k > n.
+
+Also called the binomial coefficient because it is equivalent
+to the coefficient of k-th term in polynomial expansion of the
+expression (1 + x)**n.
-Raises TypeError if the arguments are not integers.
-Raises ValueError if the arguments are negative or if k > n.
+Raises TypeError if either of the arguments are not integers.
+Raises ValueError if either of the arguments are negative.
[clinic start generated code]*/
static PyObject *
math_comb_impl(PyObject *module, PyObject *n, PyObject *k)
-/*[clinic end generated code: output=bd2cec8d854f3493 input=2f336ac9ec8242f9]*/
+/*[clinic end generated code: output=bd2cec8d854f3493 input=9a05315af2518709]*/
{
PyObject *result = NULL, *factor = NULL, *temp;
int overflow, cmp;
@@ -3173,9 +3177,8 @@ math_comb_impl(PyObject *module, PyObject *n, PyObject *k)
}
if (Py_SIZE(temp) < 0) {
Py_DECREF(temp);
- PyErr_SetString(PyExc_ValueError,
- "k must be an integer less than or equal to n");
- goto error;
+ result = PyLong_FromLong(0);
+ goto done;
}
cmp = PyObject_RichCompareBool(temp, k, Py_LT);
if (cmp > 0) {
generated by cgit v0.12 at 2024-11-28 16:00:04 (GMT)