ENH: add mm->q floordiv

* add support for floor division between
timedelta64 (m8) operands with generic
or specific units; type signature is
mm->q

5 files changed, 118 insertions, 3 deletions

diff --git a/numpy/core/code_generators/generate_umath.py b/numpy/core/code_generators/generate_umath.py
index f5ee02c42..108fff631 100644
--- a/numpy/core/code_generators/generate_umath.py
+++ b/numpy/core/code_generators/generate_umath.py
@@ -315,7 +315,7 @@ defdict = {
           TD(intfltcmplx),
           [TypeDescription('m', FullTypeDescr, 'mq', 'm'),
            TypeDescription('m', FullTypeDescr, 'md', 'm'),
-           #TypeDescription('m', FullTypeDescr, 'mm', 'd'),
+           TypeDescription('m', FullTypeDescr, 'mm', 'q'),
           ],
           TD(O, f='PyNumber_FloorDivide'),
           ),
diff --git a/numpy/core/src/umath/loops.c.src b/numpy/core/src/umath/loops.c.src
index f96e621b8..611bd02a5 100644
--- a/numpy/core/src/umath/loops.c.src
+++ b/numpy/core/src/umath/loops.c.src
@@ -1619,6 +1619,31 @@ TIMEDELTA_mm_m_remainder(char **args, npy_intp *dimensions, npy_intp *steps, voi
     }
 }
 
+NPY_NO_EXPORT void
+TIMEDELTA_mm_q_floor_divide(char **args, npy_intp *dimensions, npy_intp *steps, void *NPY_UNUSED(func))
+{
+    BINARY_LOOP {
+        const npy_timedelta in1 = *(npy_timedelta *)ip1;
+        const npy_timedelta in2 = *(npy_timedelta *)ip2;
+        if (in1 == NPY_DATETIME_NAT || in2 == NPY_DATETIME_NAT) {
+            npy_set_floatstatus_invalid();
+            *((npy_timedelta *)op1) = 0;
+        }
+        else if (in2 == 0) {
+            npy_set_floatstatus_divbyzero();
+            *((npy_timedelta *)op1) = 0;
+        }
+        else {
+            if (((in1 > 0) != (in2 > 0)) && (in1 % in2 != 0)) {
+                *((npy_timedelta *)op1) = in1/in2 - 1;
+            }
+            else {
+                *((npy_timedelta *)op1) = in1/in2;
+            }
+        }
+    }
+}
+
 /*
  *****************************************************************************
  **                             FLOAT LOOPS                                 **
diff --git a/numpy/core/src/umath/loops.h.src b/numpy/core/src/umath/loops.h.src
index 9b6327308..3c908121e 100644
--- a/numpy/core/src/umath/loops.h.src
+++ b/numpy/core/src/umath/loops.h.src
@@ -474,6 +474,9 @@ NPY_NO_EXPORT void
 TIMEDELTA_mm_d_divide(char **args, npy_intp *dimensions, npy_intp *steps, void *NPY_UNUSED(func));
 
 NPY_NO_EXPORT void
+TIMEDELTA_mm_q_floor_divide(char **args, npy_intp *dimensions, npy_intp *steps, void *NPY_UNUSED(func));
+
+NPY_NO_EXPORT void
 TIMEDELTA_mm_m_remainder(char **args, npy_intp *dimensions, npy_intp *steps, void *NPY_UNUSED(func));
 
 /* Special case equivalents to above functions */
diff --git a/numpy/core/src/umath/ufunc_type_resolution.c b/numpy/core/src/umath/ufunc_type_resolution.c
index ec60d9cfd..3cf507258 100644
--- a/numpy/core/src/umath/ufunc_type_resolution.c
+++ b/numpy/core/src/umath/ufunc_type_resolution.c
@@ -1114,7 +1114,16 @@ PyUFunc_DivisionTypeResolver(PyUFuncObject *ufunc,
             }
             out_dtypes[1] = out_dtypes[0];
             Py_INCREF(out_dtypes[1]);
+
+            /*
+             * TODO: split function into truediv and floordiv resolvers
+             */
+            if (strcmp(ufunc->name, "floor_divide") == 0) {
+                out_dtypes[2] = PyArray_DescrFromType(NPY_LONGLONG);
+            }
+            else {
             out_dtypes[2] = PyArray_DescrFromType(NPY_DOUBLE);
+            }
             if (out_dtypes[2] == NULL) {
                 Py_DECREF(out_dtypes[0]);
                 out_dtypes[0] = NULL;
diff --git a/numpy/core/tests/test_datetime.py b/numpy/core/tests/test_datetime.py
index b2ce0402a..cb7555a34 100644
--- a/numpy/core/tests/test_datetime.py
+++ b/numpy/core/tests/test_datetime.py
@@ -1081,6 +1081,86 @@ class TestDateTime(object):
                 check(np.timedelta64(0), f, nat)
                 check(nat, f, nat)
 
+    @pytest.mark.parametrize("op1, op2, exp", [
+        # m8 same units round down
+        (np.timedelta64(7, 's'),
+         np.timedelta64(4, 's'),
+         1),
+        # m8 same units round down with negative
+        (np.timedelta64(7, 's'),
+         np.timedelta64(-4, 's'),
+         -2),
+        # m8 same units negative no round down
+        (np.timedelta64(8, 's'),
+         np.timedelta64(-4, 's'),
+         -2),
+        # m8 different units
+        (np.timedelta64(1, 'm'),
+         np.timedelta64(31, 's'),
+         1),
+        # m8 generic units
+        (np.timedelta64(1890),
+         np.timedelta64(31),
+         60),
+        # Y // M works
+        (np.timedelta64(2, 'Y'),
+         np.timedelta64('13', 'M'),
+         1),
+        # handle 1D arrays
+        (np.array([1, 2, 3], dtype='m8'),
+         np.array([2], dtype='m8'),
+         np.array([0, 1, 1], dtype=np.int64)),
+        ])
+    def test_timedelta_floor_divide(self, op1, op2, exp):
+        assert_equal(op1 // op2, exp)
+
+    @pytest.mark.parametrize("op1, op2", [
+        # div by 0
+        (np.timedelta64(10, 'us'),
+         np.timedelta64(0, 'us')),
+        # div with NaT
+        (np.timedelta64('NaT'),
+         np.timedelta64(50, 'us')),
+        # special case for int64 min
+        # in integer floor division
+        (np.timedelta64(np.iinfo(np.int64).min),
+         np.timedelta64(-1)),
+        ])
+    def test_timedelta_floor_div_warnings(self, op1, op2):
+        with assert_warns(RuntimeWarning):
+            actual = op1 // op2
+            assert_equal(actual, 0)
+            assert_equal(actual.dtype, np.int64)
+
+    @pytest.mark.parametrize("val1, val2", [
+        # the smallest integer that can't be represented
+        # exactly in a double should be preserved if we avoid
+        # casting to double in floordiv operation
+        (9007199254740993, 1),
+        # stress the alternate floordiv code path where
+        # operand signs don't match and remainder isn't 0
+        (9007199254740999, -2),
+        ])
+    def test_timedelta_floor_div_precision(self, val1, val2):
+        op1 = np.timedelta64(val1)
+        op2 = np.timedelta64(val2)
+        actual = op1 // op2
+        # Python reference integer floor
+        expected = val1 // val2
+        assert_equal(actual, expected)
+
+    @pytest.mark.parametrize("val1, val2", [
+        # years and months sometimes can't be unambiguously
+        # divided for floor division operation
+        (np.timedelta64(7, 'Y'),
+         np.timedelta64(3, 's')),
+        (np.timedelta64(7, 'M'),
+         np.timedelta64(1, 'D')),
+        ])
+    def test_timedelta_floor_div_error(self, val1, val2):
+        with assert_raises_regex(TypeError, "common metadata divisor"):
+            val1 // val2
+
     def test_datetime_divide(self):
         for dta, tda, tdb, tdc, tdd in \
                     [
@@ -1111,8 +1191,6 @@ class TestDateTime(object):
             assert_equal(tda / tdd, 60.0)
             assert_equal(tdd / tda, 1.0 / 60.0)
 
-            # m8 // m8
-            assert_raises(TypeError, np.floor_divide, tda, tdb)
             # int / m8
             assert_raises(TypeError, np.divide, 2, tdb)
             # float / m8