MAINT: formatting, remove version, rework flags

6 files changed, 53 insertions, 65 deletions

diff --git a/doc/source/reference/c-api.generalized-ufuncs.rst b/doc/source/reference/c-api.generalized-ufuncs.rst
index dce198013..b59f077ad 100644
--- a/doc/source/reference/c-api.generalized-ufuncs.rst
+++ b/doc/source/reference/c-api.generalized-ufuncs.rst
@@ -149,11 +149,13 @@ Notes:
 Here are some examples of signatures:
 
 +-------------+----------------------------+-----------------------------------+
-| add         | ``(),()->()``              |                                   |
+| name        | signature                  | common usage                      |
++=============+============================+===================================+
+| add         | ``(),()->()``              | binary ufunc                      |
 +-------------+----------------------------+-----------------------------------+
-| sum1d       | ``(i)->()``                |                                   |
+| sum1d       | ``(i)->()``                | reduction                         |
 +-------------+----------------------------+-----------------------------------+
-| inner1d     | ``(i),(i)->()``            |                                   |
+| inner1d     | ``(i),(i)->()``            | vector-vector multiplication      |
 +-------------+----------------------------+-----------------------------------+
 | matmat      | ``(m,n),(n,p)->(m,p)``     | matrix multiplication             |
 +-------------+----------------------------+-----------------------------------+
@@ -167,10 +169,15 @@ Here are some examples of signatures:
 |             |                            | outer over the second to last,    |
 |             |                            | and loop/broadcast over the rest. |
 +-------------+----------------------------+-----------------------------------+
-| cross1d     | ``(3),(3)->(3)``           | cross product where the last      |
-|             |                            | dimension must be 3               |
+|  cross1d    | ``(3),(3)->(3)``           | cross product where the last      |
+|             |                            | dimension is frozen and must be 3 |
 +-------------+----------------------------+-----------------------------------+
 
+.. _frozen:
+
+The last is an instance of freezing a core dimension and can be used to
+improve ufunc performance
+
 C-API for implementing Elementary Functions
 -------------------------------------------
 
diff --git a/doc/source/reference/c-api.types-and-structures.rst b/doc/source/reference/c-api.types-and-structures.rst
index 51818142a..0766f5a3f 100644
--- a/doc/source/reference/c-api.types-and-structures.rst
+++ b/doc/source/reference/c-api.types-and-structures.rst
@@ -734,8 +734,8 @@ PyUFunc_Type
           npy_uint32 *op_flags;
           npy_uint32 *iter_flags;
           /* new in API version 0x0000000D */
-          npy_intp *core_dim_sizes; 
-          npy_intp *core_dim_flags; 
+          npy_intp *core_dim_sizes;
+          npy_intp *core_dim_flags;
 
       } PyUFuncObject;
 
@@ -796,11 +796,9 @@ PyUFunc_Type
        specifies how many different 1-d loops (of the builtin data
        types) are available.
 
-   .. c:member:: int PyUFuncObject.version
+   .. c:member:: int PyUFuncObject.reserved1
 
-       The ``NPY_API_VERSION`` used during the call to
-       :c:func:`PyUFunc_FromFuncAndDataAndSignature`. If less than
-        0x0000000D, ``core_dim_sizes`` and ``core_dim_flags`` will be ignored.
+       Unused.
 
    .. c:member:: char *PyUFuncObject.name
 
@@ -901,15 +899,15 @@ PyUFunc_Type
    .. c:member:: npy_intp *PyUFuncObject.core_dim_sizes
 
        For each distinct core dimension, the possible
-       "frozen" size (``-1`` if not frozen)
+       :ref:`frozen <frozen>` size (``-1`` if not frozen)
 
    .. c:member:: npy_uint32 *PyUFuncObject.core_dim_flags
 
-       For each distinct core dimension, a set of flags ``OR`` ed together:
+       For each distinct core dimension, a set of ``UFUNC_CORE_DIM*`` flags
 
-       - :c:data:`UFUNC_CORE_CAN_IGNORE` if the dim name ends in ``?``
-       - :c:data:`UFUNC_CORE_DIM_SIZE_UNSET` if the dim size will be
-         determined by the operands (not frozen)
+       - :c:data:`UFUNC_CORE_DIM_CAN_IGNORE` if the dim name ends in ``?``
+       - :c:data:`UFUNC_CORE_DIM_SIZE_INFERRED` if the dim size will be
+         determined from the operands and not from a :ref:`frozen <frozen>` signature
 
 PyArrayIter_Type
 ----------------
diff --git a/numpy/core/include/numpy/ufuncobject.h b/numpy/core/include/numpy/ufuncobject.h
index e24da04af..4786e73d7 100644
--- a/numpy/core/include/numpy/ufuncobject.h
+++ b/numpy/core/include/numpy/ufuncobject.h
@@ -130,8 +130,8 @@ typedef struct _tagPyUFuncObject {
         /* The number of elements in 'functions' and 'data' */
         int ntypes;
 
-        /* Used to be unused field 'check_return', repurposed in 1.16 */
-        const int version;
+        /* Used to be unused field 'check_return' */
+        int reserved1;
 
         /* The name of the ufunc */
         const char *name;
@@ -219,9 +219,7 @@ typedef struct _tagPyUFuncObject {
         npy_intp *core_dim_sizes;
 
         /*
-         * for each distinct core dimension, a set of flags OR'd together
-         * e.g., UFUNC_CORE_DIM_CAN_IGNORE if signature has ?
-         *       UFUNC_CORE_DIM_SIZE_UNSET for non-frozen dimensions.
+         * for each distinct core dimension, a set of UFUNC_CORE_DIM* flags
          */
         npy_uint32 *core_dim_flags;
 
@@ -232,7 +230,7 @@ typedef struct _tagPyUFuncObject {
 #include "arrayobject.h"
 /* Generalized ufunc; 0x0001 reserved for possible use as CORE_ENABLED */
 /* the core dimension's size will be determined by the operands. */
-#define UFUNC_CORE_DIM_SIZE_UNSET 0x0002
+#define UFUNC_CORE_DIM_SIZE_INFERRED 0x0002
 /* the core dimension may be absent */
 #define UFUNC_CORE_DIM_CAN_IGNORE 0x0004
 /* flags inferred during execution */
diff --git a/numpy/core/src/umath/_umath_tests.c.src b/numpy/core/src/umath/_umath_tests.c.src
index f0347cef8..8cb74f177 100644
--- a/numpy/core/src/umath/_umath_tests.c.src
+++ b/numpy/core/src/umath/_umath_tests.c.src
@@ -335,29 +335,29 @@ defdict = {
     Ufunc(2, 1, None_,
         r'''inner on the last dimension and broadcast on the rest \n"
         "     \"(i),(i)->()\" \n''',
-          TD('ld'),
-          ),
+        TD('ld'),
+        ),
 'innerwt' :
     Ufunc(3, 1, None_,
-          r'''inner1d with a weight argument \n"
-          "     \"(i),(i),(i)->()\" \n''',
-          TD('ld'),
-          ),
+        r'''inner1d with a weight argument \n"
+        "     \"(i),(i),(i)->()\" \n''',
+        TD('ld'),
+        ),
 }
 
 */
 
 static PyUFuncGenericFunction inner1d_functions[] = { LONG_inner1d, DOUBLE_inner1d };
-static void * inner1d_data[] = { (void *)NULL, (void *)NULL };
+static void *inner1d_data[] = { (void *)NULL, (void *)NULL };
 static char inner1d_signatures[] = { NPY_LONG, NPY_LONG, NPY_LONG, NPY_DOUBLE, NPY_DOUBLE, NPY_DOUBLE };
 static PyUFuncGenericFunction innerwt_functions[] = { LONG_innerwt, DOUBLE_innerwt };
-static void * innerwt_data[] = { (void *)NULL, (void *)NULL };
+static void *innerwt_data[] = { (void *)NULL, (void *)NULL };
 static char innerwt_signatures[] = { NPY_LONG, NPY_LONG, NPY_LONG, NPY_LONG, NPY_DOUBLE, NPY_DOUBLE, NPY_DOUBLE, NPY_DOUBLE };
 static PyUFuncGenericFunction matrix_multiply_functions[] = { LONG_matrix_multiply, FLOAT_matrix_multiply, DOUBLE_matrix_multiply };
 static void *matrix_multiply_data[] = { (void *)NULL, (void *)NULL, (void *)NULL };
 static char matrix_multiply_signatures[] = { NPY_LONG, NPY_LONG, NPY_LONG,  NPY_FLOAT, NPY_FLOAT, NPY_FLOAT,  NPY_DOUBLE, NPY_DOUBLE, NPY_DOUBLE };
 static PyUFuncGenericFunction cross1d_functions[] = { LONG_cross1d, DOUBLE_cross1d };
-static void * cross1d_data[] = { (void *)NULL, (void *)NULL };
+static void *cross1d_data[] = { (void *)NULL, (void *)NULL };
 static char cross1d_signatures[] = { NPY_LONG, NPY_LONG, NPY_LONG, NPY_DOUBLE, NPY_DOUBLE, NPY_DOUBLE };
 static PyUFuncGenericFunction euclidean_pdist_functions[] =
                             { FLOAT_euclidean_pdist, DOUBLE_euclidean_pdist };
@@ -366,7 +366,7 @@ static char euclidean_pdist_signatures[] = { NPY_FLOAT, NPY_FLOAT,
                                              NPY_DOUBLE, NPY_DOUBLE };
 
 static PyUFuncGenericFunction cumsum_functions[] = { LONG_cumsum, DOUBLE_cumsum };
-static void * cumsum_data[] = { (void *)NULL, (void *)NULL };
+static void *cumsum_data[] = { (void *)NULL, (void *)NULL };
 static char cumsum_signatures[] = { NPY_LONG, NPY_LONG, NPY_DOUBLE, NPY_DOUBLE };
 
 
@@ -527,7 +527,7 @@ UMath_Tests_test_signature(PyObject *NPY_UNUSED(dummy), PyObject *args)
             goto fail;
         }
         for (i = 0; i < core_num_ixs; i++) {
-            PyObject * val = PyLong_FromLong(f->core_dim_ixs[i]);
+            PyObject *val = PyLong_FromLong(f->core_dim_ixs[i]);
             PyTuple_SET_ITEM(core_dim_ixs, i, val);
         }
     }
@@ -541,7 +541,7 @@ UMath_Tests_test_signature(PyObject *NPY_UNUSED(dummy), PyObject *args)
             goto fail;
         }
         for (i = 0; i < f->core_num_dim_ix; i++) {
-            PyObject * val = PyLong_FromLong(f->core_dim_flags[i]);
+            PyObject *val = PyLong_FromLong(f->core_dim_flags[i]);
             PyTuple_SET_ITEM(core_dim_flags, i, val);
         }
     }
@@ -555,7 +555,7 @@ UMath_Tests_test_signature(PyObject *NPY_UNUSED(dummy), PyObject *args)
             goto fail;
         }
         for (i = 0; i < f->core_num_dim_ix; i++) {
-            PyObject * val = PyLong_FromLong(f->core_dim_sizes[i]);
+            PyObject *val = PyLong_FromLong(f->core_dim_sizes[i]);
             PyTuple_SET_ITEM(core_dim_sizes, i, val);
         }
     }
diff --git a/numpy/core/src/umath/ufunc_object.c b/numpy/core/src/umath/ufunc_object.c
index c3e1c62a8..5d477d479 100644
--- a/numpy/core/src/umath/ufunc_object.c
+++ b/numpy/core/src/umath/ufunc_object.c
@@ -652,7 +652,7 @@ _parse_signature(PyUFuncObject *ufunc, const char *signature)
                 var_names[ix] = signature + i;
                 ufunc->core_dim_sizes[ix] = frozen_size;
                 if (frozen_size < 0) {
-                    ufunc->core_dim_flags[ix] |= UFUNC_CORE_DIM_SIZE_UNSET;
+                    ufunc->core_dim_flags[ix] |= UFUNC_CORE_DIM_SIZE_INFERRED;
                 }
                 if (can_ignore) {
                     ufunc->core_dim_flags[ix] |= UFUNC_CORE_DIM_CAN_IGNORE;
@@ -2353,7 +2353,7 @@ _parse_axis_arg(PyUFuncObject *ufunc, int core_num_dims[], PyObject *axis,
  *    an output argument that were not specified in an input argument,
  *    and whose size could not be inferred from a passed in output
  *    argument, would have their size set to 1.
- *  * Core dimensions may be fixed, new in ufunc->version 1 (NumPy 1.16)
+ *  * Core dimensions may be fixed, new in NumPy 1.16
  */
 static int
 _get_coredim_sizes(PyUFuncObject *ufunc, PyArrayObject **op,
@@ -2492,23 +2492,9 @@ _initialize_variable_parts(PyUFuncObject *ufunc,
     for (i = 0; i < ufunc->nargs; i++) {
         op_core_num_dims[i] = ufunc->core_num_dims[i];
     }
-    if (ufunc->version >= 0x0000d) {
-        for (i = 0; i < ufunc->core_num_dim_ix; i++) {
-            core_dim_sizes[i] = ufunc->core_dim_sizes[i];
-            core_dim_flags[i] = ufunc->core_dim_flags[i];
-        }
-    }
-    else if (ufunc->version == 0) {
-        for (i = 0; i < ufunc->core_num_dim_ix; i++) {
-            core_dim_sizes[i] = -1;
-            core_dim_flags[i] = UFUNC_CORE_DIM_SIZE_UNSET;
-        }
-    }
-    else {
-        PyErr_Format(PyExc_TypeError,
-                     "'%s': unrecognized version number %d or corrupted data.",
-                     ufunc_get_name_cstr(ufunc), ufunc->version);
-        return -1;
+    for (i = 0; i < ufunc->core_num_dim_ix; i++) {
+        core_dim_sizes[i] = ufunc->core_dim_sizes[i];
+        core_dim_flags[i] = ufunc->core_dim_flags[i];
     }
     return 0;
 }
@@ -4868,7 +4854,6 @@ PyUFunc_FromFuncAndDataAndSignature(PyUFuncGenericFunction *func, void **data,
         return NULL;
     }
     memset(ufunc, 0, sizeof(PyUFuncObject));
-    *((int*)&ufunc->version) = NPY_API_VERSION;
     PyObject_Init((PyObject *)ufunc, &PyUFunc_Type);
 
     ufunc->nin = nin;
diff --git a/numpy/core/tests/test_ufunc.py b/numpy/core/tests/test_ufunc.py
index c0cca9e56..fbb6cfcd5 100644
--- a/numpy/core/tests/test_ufunc.py
+++ b/numpy/core/tests/test_ufunc.py
@@ -287,7 +287,7 @@ class TestUfunc(object):
         pass
 
     # from include/numpy/ufuncobject.h
-    size_unset = 2
+    size_inferred = 2
     can_ignore = 4
     def test_signature0(self):
         # the arguments to test_signature are: nin, nout, core_signature
@@ -296,7 +296,7 @@ class TestUfunc(object):
         assert_equal(enabled, 1)
         assert_equal(num_dims, (1,  1,  0))
         assert_equal(ixs, (0, 0))
-        assert_equal(flags, (self.size_unset,))
+        assert_equal(flags, (self.size_inferred,))
         assert_equal(sizes, (-1,))
 
     def test_signature1(self):
@@ -316,7 +316,7 @@ class TestUfunc(object):
         assert_equal(enabled, 1)
         assert_equal(num_dims, (2, 1, 1))
         assert_equal(ixs, (0, 1, 2, 3))
-        assert_equal(flags, (self.size_unset,)*4)
+        assert_equal(flags, (self.size_inferred,)*4)
         assert_equal(sizes, (-1, -1, -1, -1))
 
     def test_signature3(self):
@@ -325,7 +325,7 @@ class TestUfunc(object):
         assert_equal(enabled, 1)
         assert_equal(num_dims, (2, 1, 2))
         assert_equal(ixs, (0, 1, 2, 1, 3))
-        assert_equal(flags, (self.size_unset,)*4)
+        assert_equal(flags, (self.size_inferred,)*4)
         assert_equal(sizes, (-1, -1, -1, -1))
 
     def test_signature4(self):
@@ -335,7 +335,7 @@ class TestUfunc(object):
         assert_equal(enabled, 1)
         assert_equal(num_dims, (2, 2, 2))
         assert_equal(ixs, (0, 1, 1, 2, 0, 2))
-        assert_equal(flags, (self.size_unset,)*3)
+        assert_equal(flags, (self.size_inferred,)*3)
         assert_equal(sizes, (-1, -1, -1))
 
     def test_signature5(self):
@@ -345,9 +345,9 @@ class TestUfunc(object):
         assert_equal(enabled, 1)
         assert_equal(num_dims, (2, 2, 2))
         assert_equal(ixs, (0, 1, 1, 2, 0, 2))
-        assert_equal(flags, (self.size_unset | self.can_ignore,
-                             self.size_unset,
-                             self.size_unset | self.can_ignore))
+        assert_equal(flags, (self.size_inferred | self.can_ignore,
+                             self.size_inferred,
+                             self.size_inferred | self.can_ignore))
         assert_equal(sizes, (-1, -1, -1))
 
     def test_signature6(self):
@@ -365,7 +365,7 @@ class TestUfunc(object):
         assert_equal(enabled, 1)
         assert_equal(num_dims, (1, 2, 1, 1))
         assert_equal(ixs, (0, 0, 0, 1, 2))
-        assert_equal(flags, (0, self.size_unset, 0))
+        assert_equal(flags, (0, self.size_inferred, 0))
         assert_equal(sizes, (3, -1, 9))
 
     def test_signature8(self):
@@ -374,7 +374,7 @@ class TestUfunc(object):
         assert_equal(enabled, 1)
         assert_equal(num_dims, (1, 2, 1, 1))
         assert_equal(ixs, (0, 0, 0, 1, 2))
-        assert_equal(flags, (self.can_ignore, self.size_unset, 0))
+        assert_equal(flags, (self.can_ignore, self.size_inferred, 0))
         assert_equal(sizes, (3, -1, 9))
 
     def test_signature_failure0(self):