Add user_cpu_context and ability to provide host_policy via it

cpp/oneapi/dal/compute.hpp

@@ -17,6 +17,7 @@
 #pragma once
 
 #include "oneapi/dal/detail/compute_ops.hpp"
+#include "oneapi/dal/detail/user_policy.hpp"
 #include "oneapi/dal/detail/spmd_policy.hpp"
 #include "oneapi/dal/spmd/communicator.hpp"
 
@@ -28,6 +29,11 @@ auto compute(Args&&... args) {
     return dal::detail::compute_dispatch(std::forward<Args>(args)...);
 }
 
+template <typename... Args>
+auto compute(detail::user_cpu_context uctx, Args&&... args) {
+    return dal::detail::compute_dispatch(uctx.get_host_policy(), std::forward<Args>(args)...);
+}
+
 #ifdef ONEDAL_DATA_PARALLEL
 template <typename... Args>
 auto compute(sycl::queue& queue, Args&&... args) {

cpp/oneapi/dal/detail/policy.hpp

@@ -103,6 +103,7 @@ class ONEDAL_EXPORT host_policy : public base {
     }
     host_policy(const host_policy&) = default;
     host_policy(host_policy&&) = default;
+    host_policy& operator=(const host_policy&) = default;
 
     static host_policy get_default() {
         return host_policy(make_default_impl());

cpp/oneapi/dal/detail/user_policy.cpp

@@ -0,0 +1,47 @@
+/*******************************************************************************
+* Copyright 2023 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.
+*******************************************************************************/
+#include "oneapi/dal/detail/user_policy.hpp"
+
+namespace oneapi::dal::detail {
+class user_cpu_context_impl {
+public:
+    user_cpu_context_impl() : policy_(host_policy::get_default()) {}
+    user_cpu_context_impl(const host_policy& policy) : policy_(policy) {}
+    void set_host_policy(const host_policy& policy) {
+        policy_ = policy;
+    }
+    host_policy get_host_policy() {
+        return policy_;
+    }
+
+private:
+    detail::host_policy policy_;
+};
+
+user_cpu_context::user_cpu_context() : impl_(new user_cpu_context_impl()) {}
+
+user_cpu_context::user_cpu_context(const host_policy& policy)
+        : impl_(new user_cpu_context_impl(policy)) {}
+
+void user_cpu_context::set_host_policy(const host_policy& policy) {
+    impl_->set_host_policy(policy);
+}
+
+host_policy user_cpu_context::get_host_policy() {
+    return impl_->get_host_policy();
+}
+
+} // namespace oneapi::dal::detail

cpp/oneapi/dal/detail/user_policy.hpp

@@ -0,0 +1,32 @@
+/*******************************************************************************
+* Copyright 2023 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.
+*******************************************************************************/
+#include "oneapi/dal/detail/policy.hpp"
+
+namespace oneapi::dal::detail {
+class user_cpu_context_impl;
+
+class user_cpu_context {
+public:
+    user_cpu_context();
+    user_cpu_context(const host_policy& policy);
+    host_policy get_host_policy();
+    void set_host_policy(const host_policy& policy);
+
+private:
+    pimpl<user_cpu_context_impl> impl_;
+};
+
+} //namespace oneapi::dal::detail

cpp/oneapi/dal/train.hpp

@@ -17,6 +17,7 @@
 #pragma once
 
 #include "oneapi/dal/detail/train_ops.hpp"
+#include "oneapi/dal/detail/user_policy.hpp"
 #include "oneapi/dal/detail/spmd_policy.hpp"
 #include "oneapi/dal/spmd/communicator.hpp"
 
@@ -28,6 +29,11 @@ auto train(Args&&... args) {
     return dal::detail::train_dispatch(std::forward<Args>(args)...);
 }
 
+template <typename... Args>
+auto train(detail::user_cpu_context uctx, Args&&... args) {
+    return dal::detail::train_dispatch(uctx.get_host_policy(), std::forward<Args>(args)...);
+}
+
 #ifdef ONEDAL_DATA_PARALLEL
 template <typename... Args>
 auto train(sycl::queue& queue, Args&&... args) {