Enable serialization in daal4py algorithm classes (uxlfoundation#2067)

* enable serialization for algorithm classes

* prevent accidental reorder of dict

* add test for serialization of kmeans

generator/wrapper_gen.py

@@ -1003,6 +1003,8 @@ def __cinit__(self):
 
 # this is our actual algorithm class for Python
 cdef class {{algo}}{{'('+iface[0]|lower+'__iface__)' if iface[0] else ''}}:
+    cdef tuple _params
+
     '''
     {{algo}}
     {{params_all|fmt('{}', 'sphinx', sep='\n')|indent(4)}}
@@ -1017,6 +1019,17 @@ def __cinit__(self,
         self.c_ptr = mk_{{algo}}(
             {{params_all|fmt('{}', 'arg_cyext', sep=',\n')|indent(25+(algo|length))}}
         )
+        current_locals = locals()
+        ordered_input_args = '''
+            {{params_all|fmt('{}', 'name', sep=' ')|indent(0)}}
+        '''.strip().split()
+        self._params = tuple(
+            current_locals[arg]
+            for arg in ordered_input_args
+        )
+
+    def __reduce__(self):
+        return (self.__class__, self._params)
 
 {% if not iface[0] %}
     # the C++ manager__iface__ (de-templatized)

tests/test_daal4py_serialization.py

@@ -0,0 +1,48 @@
+# ==============================================================================
+# Copyright 2024 Intel Corporation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+
+import pickle
+import unittest
+
+import numpy as np
+
+import daal4py
+
+
+class Test(unittest.TestCase):
+    def test_serialization_of_qr(self):
+        obj_original = daal4py.qr(fptype="float")
+        obj_deserialized = pickle.loads(pickle.dumps(obj_original))
+
+        rng = np.random.default_rng(seed=123)
+        X = rng.standard_normal(size=(10, 5))
+
+        Q_orig = obj_original.compute(X).matrixQ
+        Q_deserialized = obj_deserialized.compute(X).matrixQ
+        np.testing.assert_almost_equal(Q_orig, Q_deserialized)
+        assert Q_orig.dtype == Q_deserialized.dtype
+
+    def test_serialization_of_kmeans(self):
+        obj_original = daal4py.kmeans_init(nClusters=4)
+        obj_deserialized = pickle.loads(pickle.dumps(obj_original))
+
+        rng = np.random.default_rng(seed=123)
+        X = rng.standard_normal(size=(100, 20))
+
+        np.testing.assert_almost_equal(
+            obj_original.compute(X).centroids,
+            obj_deserialized.compute(X).centroids,
+        )