Fix nonzero result dtype win

dpctl/tensor/_copy_utils.py

@@ -586,7 +586,7 @@ def _nonzero_impl(ary):
         mask_nelems, dtype=cumsum_dt, sycl_queue=exec_q, order="C"
     )
     mask_count = ti.mask_positions(ary, cumsum, sycl_queue=exec_q)
-    indexes_dt = ti.default_device_int_type(exec_q.sycl_device)
+    indexes_dt = ti.default_device_index_type(exec_q.sycl_device)
     indexes = dpt.empty(
         (ary.ndim, mask_count),
         dtype=indexes_dt,

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,

dpctl/tests/test_usm_ndarray_indexing.py

@@ -22,6 +22,7 @@
 
 import dpctl
 import dpctl.tensor as dpt
+import dpctl.tensor._tensor_impl as ti
 from dpctl.utils import ExecutionPlacementError
 
 _all_dtypes = [
@@ -1353,7 +1354,7 @@ def test_nonzero_dtype():
     x = dpt.ones((3, 4))
     idx, idy = dpt.nonzero(x)
     # create array using device's
-    # default integral data type
-    ref = dpt.arange(8)
-    assert idx.dtype == ref.dtype
-    assert idy.dtype == ref.dtype
+    # default index data type
+    index_dt = dpt.dtype(ti.default_device_index_type(x.sycl_queue))
+    assert idx.dtype == index_dt
+    assert idy.dtype == index_dt