Add default_device_index_type(queue_or_dev) utility

This returns default index type for give device. Since all devices
are 64-bit devices, it always returns "i8".

Author: oleksandr-pavlyk

dpctl/tensor/libtensor/source/device_support_queries.cpp

@@ -71,6 +71,11 @@ std::string _default_device_bool_type(sycl::device)
     return "b1";
 }
 
+std::string _default_device_index_type(sycl::device)
+{
+    return "i8";
+}
+
 sycl::device _extract_device(py::object arg)
 {
     auto const &api = dpctl::detail::dpctl_capi::get();
@@ -115,6 +120,12 @@ std::string default_device_complex_type(py::object arg)
     return _default_device_complex_type(d);
 }
 
+std::string default_device_index_type(py::object arg)
+{
+    sycl::device d = _extract_device(arg);
+    return _default_device_index_type(d);
+}
+
 } // namespace py_internal
 } // namespace tensor
 } // namespace dpctl

dpctl/tensor/libtensor/source/device_support_queries.hpp

@@ -41,6 +41,7 @@ extern std::string default_device_fp_type(py::object);
 extern std::string default_device_int_type(py::object);
 extern std::string default_device_bool_type(py::object);
 extern std::string default_device_complex_type(py::object);
+extern std::string default_device_index_type(py::object);
 
 } // namespace py_internal
 } // namespace tensor

dpctl/tensor/libtensor/source/tensor_py.cpp

@@ -297,9 +297,13 @@ PYBIND11_MODULE(_tensor_impl, m)
 
     m.def("default_device_complex_type",
           dpctl::tensor::py_internal::default_device_complex_type,
-          "Gives default complex floating point type support by device.",
+          "Gives default complex floating point type supported by device.",
           py::arg("dev"));
 
+    m.def("default_device_index_type",
+          dpctl::tensor::py_internal::default_device_index_type,
+          "Gives default index type supported by device.", py::arg("dev"));
+
     auto tril_fn = [](dpctl::tensor::usm_ndarray src,
                       dpctl::tensor::usm_ndarray dst, py::ssize_t k,
                       sycl::queue exec_q,