Changes to advanced indexing

- Clipping now clips indices to -n <= i < n for n = axis size
- Fixed a segfault caused by a typo when copying strides

Author: ndgrigorian

dpctl/tensor/libtensor/include/kernels/advanced_indexing.hpp

@@ -54,7 +54,9 @@ template <typename indT> class ClipIndex
     {
         max_item = (max_item > 0) ? max_item : 1;
         py::ssize_t clip_ind = static_cast<py::ssize_t>(ind);
-        ind = (ind < 0) ? 0 : (clip_ind >= max_item) ? (max_item - 1) : ind;
+        ind = (ind < 0) ? (clip_ind <= -max_item) ? (0) : (clip_ind + max_item)
+              : (clip_ind >= max_item) ? (max_item - 1)
+                                       : ind;
         return;
     }
 };

dpctl/tensor/libtensor/source/advanced_indexing.cpp

@@ -197,7 +197,7 @@ std::vector<sycl::event> _populate_packed_shapes_strides_for_indexing(
             std::copy(arr_strides, arr_strides + axis_start,
                       packed_host_shapes_strides_shp->begin() +
                           2 * orthog_sh_elems);
-            std::copy(arr_strides + axis_start + ind_nd, arr_strides + inp_nd,
+            std::copy(arr_strides + axis_start + ind_nd, arr_strides + arr_nd,
                       packed_host_shapes_strides_shp->begin() +
                           2 * orthog_sh_elems + axis_start);
             std::copy(arr_strides + axis_start,