Add converting usm_array to ndarray in fallback (#921)

* Add converting usm_array to ndarray to fallback

* Replace _to_numpy with copy_to_host

* Add copy of result from host in call_origin

Author: densmirn

dpnp/dpnp_iface_arraycreation.py

@@ -196,11 +196,7 @@ def array(x1, dtype=None, copy=True, order='C', subok=False, ndmin=0, like=None)
     if not dpnp.is_type_supported(dtype) and dtype is not None:
         pass
     elif config.__DPNP_OUTPUT_DPCTL__:
-        # TODO this is workaround becasue
-        # usm_array has no element wise assignment (aka []) and
-        # has no "flat" property and
-        # "usm_data.copy_from_host" doesn't work with diffrent datatypes
-        return numpy.array(x1, dtype=dtype, copy=copy, order=order, subok=subok, ndmin=ndmin)
+        return call_origin(numpy.array, x1, dtype=dtype, copy=copy, order=order, subok=subok, ndmin=ndmin)
     elif subok is not False:
         pass
     elif copy is not True:

dpnp/dpnp_utils/dpnp_algo_utils.pyx

@@ -68,7 +68,7 @@ cdef ERROR_PREFIX = "DPNP error:"
 
 def convert_item(item):
     if getattr(item, "__sycl_usm_array_interface__", False):
-        item_converted = dpnp.asnumpy(item) 
+        item_converted = dpnp.asnumpy(item)
     elif getattr(item, "__array_interface__", False): # detect if it is a container (TODO any better way?)
         mod_name = getattr(item, "__module__", 'none')
         if (mod_name != 'numpy'):
@@ -91,7 +91,18 @@ def convert_list_args(input_list):
         result_list.append(item_converted)
 
     return result_list
-    
+
+
+def copy_from_origin(dst, src):
+    """Copy origin result to output result."""
+    if config.__DPNP_OUTPUT_DPCTL__ and hasattr(dst, "__sycl_usm_array_interface__"):
+        if src.size:
+            dst.usm_data.copy_from_host(src.reshape(-1).view("|u1"))
+    else:
+        for i in range(dst.size):
+            dst.flat[i] = src.item(i)
+
+
 def call_origin(function, *args, **kwargs):
     """
     Call fallback function for unsupported cases
@@ -138,8 +149,7 @@ def call_origin(function, *args, **kwargs):
         else:
             result = kwargs_out
 
-        for i in range(result.size):
-            result.flat[i] = result_origin.item(i)
+        copy_from_origin(result, result_origin)
 
     elif isinstance(result, tuple):
         # convert tuple(fallback_array) to tuple(result_array)
@@ -148,8 +158,7 @@ def call_origin(function, *args, **kwargs):
             res = res_origin
             if isinstance(res_origin, numpy.ndarray):
                 res = create_output_container(res_origin.shape, res_origin.dtype)
-                for i in range(res.size):
-                    res.flat[i] = res_origin.item(i)
+                copy_from_origin(res, res_origin)
             result_list.append(res)
 
         result = tuple(result_list)