Merge pull request numpy#8348 from anntzer/bincount-zero-minlength

eric-wieser · web-flow · commit 1a82adf443de · 2017-03-26T09:34:11.000+01:00
ENH: Allow bincount(..., minlength=0).
diff --git a/numpy/add_newdocs.py b/numpy/add_newdocs.py
@@ -5107,7 +5107,7 @@ def luf(lamdaexpr, *args, **kwargs):
 
 add_newdoc('numpy.core.multiarray', 'bincount',
     """
-    bincount(x, weights=None, minlength=None)
+    bincount(x, weights=None, minlength=0)
 
     Count number of occurrences of each value in array of non-negative ints.
 
diff --git a/numpy/core/src/multiarray/compiled_base.c b/numpy/core/src/multiarray/compiled_base.c
@@ -117,10 +117,10 @@ arr_bincount(PyObject *NPY_UNUSED(self), PyObject *args, PyObject *kwds)
     }
     else {
         minlength = PyArray_PyIntAsIntp(mlength);
-        if (minlength <= 0) {
+        if (minlength < 0) {
             if (!PyErr_Occurred()) {
                 PyErr_SetString(PyExc_ValueError,
-                                "minlength must be positive");
+                                "minlength must be non-negative");
             }
             goto fail;
         }
diff --git a/numpy/lib/tests/test_function_base.py b/numpy/lib/tests/test_function_base.py
@@ -2507,11 +2507,16 @@ def test_with_minlength(self):
         x = np.array([0, 1, 0, 1, 1])
         y = np.bincount(x, minlength=3)
         assert_array_equal(y, np.array([2, 3, 0]))
+        x = []
+        y = np.bincount(x, minlength=0)
+        assert_array_equal(y, np.array([]))
 
     def test_with_minlength_smaller_than_maxvalue(self):
         x = np.array([0, 1, 1, 2, 2, 3, 3])
         y = np.bincount(x, minlength=2)
         assert_array_equal(y, np.array([1, 2, 2, 2]))
+        y = np.bincount(x, minlength=0)
+        assert_array_equal(y, np.array([1, 2, 2, 2]))
 
     def test_with_minlength_and_weights(self):
         x = np.array([1, 2, 4, 5, 2])
@@ -2535,22 +2540,16 @@ def test_with_incorrect_minlength(self):
                             "'str' object cannot be interpreted",
                             lambda: np.bincount(x, minlength="foobar"))
         assert_raises_regex(ValueError,
-                            "must be positive",
+                            "must be non-negative",
                             lambda: np.bincount(x, minlength=-1))
-        assert_raises_regex(ValueError,
-                            "must be positive",
-                            lambda: np.bincount(x, minlength=0))
 
         x = np.arange(5)
         assert_raises_regex(TypeError,
                             "'str' object cannot be interpreted",
                             lambda: np.bincount(x, minlength="foobar"))
         assert_raises_regex(ValueError,
-                            "minlength must be positive",
+                            "minlength must be non-negative",
                             lambda: np.bincount(x, minlength=-1))
-        assert_raises_regex(ValueError,
-                            "minlength must be positive",
-                            lambda: np.bincount(x, minlength=0))
 
     @dec.skipif(not HAS_REFCOUNT, "python has no sys.getrefcount")
     def test_dtype_reference_leaks(self):

Original file line number	Diff line number	Diff line change
`@@ -117,10 +117,10 @@ arr_bincount(PyObject NPY_UNUSED(self), PyObject args, PyObject *kwds)`
`117`	`117`	`}`
`118`	`118`	`else {`
`119`	`119`	`minlength = PyArray_PyIntAsIntp(mlength);`
`120`		`- if (minlength <= 0) {`
	`120`	`+ if (minlength < 0) {`
`121`	`121`	`if (!PyErr_Occurred()) {`
`122`	`122`	`PyErr_SetString(PyExc_ValueError,`
`123`		`- "minlength must be positive");`
	`123`	`+ "minlength must be non-negative");`
`124`	`124`	`}`
`125`	`125`	`goto fail;`
`126`	`126`	`}`