Used _searchsorted_left instead of tensor.searchsorted to avoid synchronization

Used asynchronous `_searchsorted_left` to insert operation into execution
tree for unique_inverse and unique_all functions.

Author: oleksandr-pavlyk

dpctl/tensor/_set_functions.py

@@ -29,7 +29,11 @@
     default_device_index_type,
     mask_positions,
 )
-from ._tensor_sorting_impl import _argsort_ascending, _sort_ascending
+from ._tensor_sorting_impl import (
+    _argsort_ascending,
+    _searchsorted_left,
+    _sort_ascending,
+)
 
 __all__ = [
     "unique_values",
@@ -365,7 +369,7 @@ def unique_inverse(x):
     unique_vals = dpt.empty(
         n_uniques, dtype=x.dtype, usm_type=x_usm_type, sycl_queue=exec_q
     )
-    ht_ev, _ = _extract(
+    ht_ev, uv_ev = _extract(
         src=s,
         cumsum=cumsum,
         axis_start=0,
@@ -403,8 +407,21 @@ def unique_inverse(x):
         depends=[set_ev, extr_ev],
     )
     host_tasks.append(ht_ev)
+
+    inv_dt = dpt.int64 if x.size > dpt.iinfo(dpt.int32).max else dpt.int32
+    inv = dpt.empty_like(x, dtype=inv_dt, order="C")
+    ht_ev, _ = _searchsorted_left(
+        hay=unique_vals,
+        needles=x,
+        positions=inv,
+        sycl_queue=exec_q,
+        depends=[
+            uv_ev,
+        ],
+    )
+    host_tasks.append(ht_ev)
+
     dpctl.SyclEvent.wait_for(host_tasks)
-    inv = dpt.searchsorted(unique_vals, x)
     return UniqueInverseResult(unique_vals, inv)
 
 
@@ -532,7 +549,7 @@ def unique_all(x: dpt.usm_ndarray) -> UniqueAllResult:
     unique_vals = dpt.empty(
         n_uniques, dtype=x.dtype, usm_type=x_usm_type, sycl_queue=exec_q
     )
-    ht_ev, _ = _extract(
+    ht_ev, uv_ev = _extract(
         src=s,
         cumsum=cumsum,
         axis_start=0,
@@ -562,15 +579,29 @@ def unique_all(x: dpt.usm_ndarray) -> UniqueAllResult:
     )
     host_tasks.append(ht_ev)
     _counts = dpt.empty_like(cum_unique_counts[1:])
-    ht_ev, _ = _subtract(
+    ht_ev, sub_ev = _subtract(
         src1=cum_unique_counts[1:],
         src2=cum_unique_counts[:-1],
         dst=_counts,
         sycl_queue=exec_q,
         depends=[set_ev, extr_ev],
     )
     host_tasks.append(ht_ev)
-    inv = dpt.searchsorted(unique_vals, x)
+
+    inv_dt = dpt.int64 if x.size > dpt.iinfo(dpt.int32).max else dpt.int32
+    inv = dpt.empty_like(x, dtype=inv_dt, order="C")
+    ht_ev, _ = _searchsorted_left(
+        hay=unique_vals,
+        needles=x,
+        positions=inv,
+        sycl_queue=exec_q,
+        depends=[
+            uv_ev,
+        ],
+    )
+    host_tasks.append(ht_ev)
+
+    dpctl.SyclEvent.wait_for(host_tasks)
     return UniqueAllResult(
         unique_vals,
         sorting_ids[cum_unique_counts[:-1]],