MNT: Remove unnecessary stride/flags cleanup.

This code is unnecessary with changed flags behavior. It would
only serve the purpose of making strides look nicer for the
user.
The UpdateFlags was only required since 1-dim axis being removed
might change contiguous flags. But this cannot happen now.

2 files changed, 5 insertions, 40 deletions

diff --git a/numpy/core/src/multiarray/multiarraymodule.c b/numpy/core/src/multiarray/multiarraymodule.c
index 133652a90..1f455f528 100644
--- a/numpy/core/src/multiarray/multiarraymodule.c
+++ b/numpy/core/src/multiarray/multiarraymodule.c
@@ -1517,26 +1517,18 @@ PyArray_EquivTypenums(int typenum1, int typenum2)
 /*** END C-API FUNCTIONS **/
 
 static PyObject *
-_prepend_ones(PyArrayObject *arr, int nd, int ndmin, NPY_ORDER order)
+_prepend_ones(PyArrayObject *arr, int nd, int ndmin)
 {
     npy_intp newdims[NPY_MAXDIMS];
     npy_intp newstrides[NPY_MAXDIMS];
-    npy_intp newstride;
     int i, k, num;
     PyArrayObject *ret;
     PyArray_Descr *dtype;
 
-    if (order == NPY_FORTRANORDER || PyArray_ISFORTRAN(arr) || PyArray_NDIM(arr) == 0) {
-        newstride = PyArray_DESCR(arr)->elsize;
-    }
-    else {
-        newstride = PyArray_STRIDES(arr)[0] * PyArray_DIMS(arr)[0];
-    }
-
     num = ndmin - nd;
     for (i = 0; i < num; i++) {
         newdims[i] = 1;
-        newstrides[i] = newstride;
+        newstrides[i] = PyArray_DESCR(arr)->elsize;
     }
     for (i = num; i < ndmin; i++) {
         k = i - num;
@@ -1677,7 +1669,7 @@ _array_fromobject(PyObject *NPY_UNUSED(ignored), PyObject *args, PyObject *kws)
      * create a new array from the same data with ones in the shape
      * steals a reference to ret
      */
-    return _prepend_ones(ret, nd, ndmin, order);
+    return _prepend_ones(ret, nd, ndmin);
 
 clean_type:
     Py_XDECREF(type);
diff --git a/numpy/core/src/multiarray/shape.c b/numpy/core/src/multiarray/shape.c
index 33ec6a629..91d18474c 100644
--- a/numpy/core/src/multiarray/shape.c
+++ b/numpy/core/src/multiarray/shape.c
@@ -267,32 +267,6 @@ PyArray_Newshape(PyArrayObject *self, PyArray_Dims *newdims,
             }
         }
     }
-    else if (ndim > 0) {
-        /*
-         * replace any 0-valued strides with
-         * appropriate value to preserve contiguousness
-         */
-        if (order == NPY_FORTRANORDER) {
-            if (dimensions[0] == 1) {
-                strides[0] = PyArray_DESCR(self)->elsize;
-            }
-            for (i = 1; i < ndim; i++) {
-                if (dimensions[i] == 1) {
-                    strides[i] = strides[i-1] * dimensions[i-1];
-                }
-            }
-        }
-        else {
-            if (dimensions[ndim-1] == 1) {
-                strides[ndim-1] = PyArray_DESCR(self)->elsize;
-            }
-            for (i = ndim - 2; i > -1; i--) {
-                if (dimensions[i] == 1) {
-                    strides[i] = strides[i+1] * dimensions[i+1];
-                }
-            }
-        }
-    }
 
     Py_INCREF(PyArray_DESCR(self));
     ret = (PyArrayObject *)PyArray_NewFromDescr(Py_TYPE(self),
@@ -1164,6 +1138,8 @@ build_shape_string(npy_intp n, npy_intp *vals)
  * WARNING: If an axis flagged for removal has a shape equal to zero,
  *          the array will point to invalid memory. The caller must
  *          validate this!
+ *          If an axis flagged for removal has a shape larger then one,
+ *          the arrays contiguous flags may require updating.
  *
  * For example, this can be used to remove the reduction axes
  * from a reduction result once its computation is complete.
@@ -1186,7 +1162,4 @@ PyArray_RemoveAxesInPlace(PyArrayObject *arr, npy_bool *flags)
 
     /* The final number of dimensions */
     fa->nd = idim_out;
-    
-    /* Update contiguous flags */
-    PyArray_UpdateFlags(arr, NPY_ARRAY_C_CONTIGUOUS | NPY_ARRAY_F_CONTIGUOUS);
 }