add empty stubs for xpress for model_builder

ortools/linear_solver/proto_solver/BUILD.bazel

@@ -167,3 +167,26 @@ cc_library(
         "@com_google_absl//absl/status:statusor",
     ],
 )
+
+cc_library(
+    name = "xpress_proto_solver",
+    srcs = ["xpress_proto_solver.cc"],
+    hdrs = ["xpress_proto_solver.h"],
+    deps = [
+        "//ortools/base:timer",
+        "//ortools/xpress:environment",
+        "//ortools/linear_solver:linear_solver_cc_proto",
+        "//ortools/linear_solver:model_validator",
+        "//ortools/util:lazy_mutable_copy",
+        "@com_google_absl//absl/base:core_headers",
+        "@com_google_absl//absl/cleanup",
+        "@com_google_absl//absl/log",
+        "@com_google_absl//absl/log:check",
+        "@com_google_absl//absl/status",
+        "@com_google_absl//absl/status:statusor",
+        "@com_google_absl//absl/strings",
+        "@com_google_absl//absl/strings:str_format",
+        "@com_google_absl//absl/time",
+        "@com_google_absl//absl/types:optional",
+    ],
+)

ortools/linear_solver/proto_solver/xpress_proto_solver.cc

@@ -0,0 +1,56 @@
+// Copyright 2010-2022 Google LLC
+// 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 <algorithm>
+#include <cmath>
+#include <cstdint>
+#include <limits>
+#include <memory>
+#include <numeric>
+#include <string>
+#include <vector>
+
+#include "absl/base/attributes.h"
+#include "absl/cleanup/cleanup.h"
+#include "absl/log/check.h"
+#include "absl/status/status.h"
+#include "absl/status/statusor.h"
+#include "absl/strings/str_cat.h"
+#include "absl/strings/str_format.h"
+#include "absl/strings/str_join.h"
+#include "absl/strings/str_split.h"
+#include "absl/strings/string_view.h"
+#include "absl/time/clock.h"
+#include "absl/time/time.h"
+#include "absl/types/optional.h"
+#include "ortools/base/logging.h"
+#include "ortools/base/status_macros.h"
+#include "ortools/base/timer.h"
+#include "ortools/linear_solver/linear_solver.pb.h"
+#include "ortools/linear_solver/model_validator.h"
+#include "ortools/linear_solver/proto_solver/xpress_proto_solver.h"
+#include "ortools/util/lazy_mutable_copy.h"
+#include "ortools/xpress/environment.h"
+
+namespace operations_research {
+
+absl::StatusOr<MPSolutionResponse> XpressSolveProto(
+    const MPModelRequest& request) {
+  MPSolutionResponse response;
+  response.set_status(MPSOLVER_SOLVER_TYPE_UNAVAILABLE);
+  response.set_status_str(std::string("XPressMP not supported"));  // NOLINT
+
+  return response;
+}
+
+}  // namespace operations_research

ortools/linear_solver/proto_solver/xpress_proto_solver.h

@@ -0,0 +1,32 @@
+// Copyright 2010-2022 Google LLC
+// 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.
+
+#ifndef OR_TOOLS_LINEAR_SOLVER_PROTO_SOLVER_XPRESS_PROTO_SOLVER_H_
+#define OR_TOOLS_LINEAR_SOLVER_PROTO_SOLVER_XPRESS_PROTO_SOLVER_H_
+
+#include <string>
+
+#include "absl/status/status.h"
+#include "absl/status/statusor.h"
+#include "absl/strings/string_view.h"
+#include "ortools/xpress/environment.h"
+#include "ortools/linear_solver/linear_solver.pb.h"
+
+namespace operations_research {
+
+// Solves the input request.
+absl::StatusOr<MPSolutionResponse> XpressSolveProto(
+    const MPModelRequest& request);
+
+}  // namespace operations_research
+#endif  // OR_TOOLS_LINEAR_SOLVER_PROTO_SOLVER_XPRESS_PROTO_SOLVER_H_

ortools/linear_solver/wrappers/BUILD.bazel

@@ -45,8 +45,10 @@ cc_library(
         "//ortools/linear_solver/proto_solver:pdlp_proto_solver",
         "//ortools/linear_solver/proto_solver:sat_proto_solver",
         "//ortools/linear_solver/proto_solver:scip_proto_solver",
+        "//ortools/linear_solver/proto_solver:xpress_proto_solver",
         "//ortools/lp_data:lp_parser",
         "//ortools/lp_data:mps_reader",
         "//ortools/util:logging",
+        "//ortools/xpress:environment",
     ],
 )

ortools/linear_solver/wrappers/model_builder_helper.cc

@@ -26,11 +26,14 @@
 #include "ortools/base/helpers.h"
 #include "ortools/base/logging.h"
 #include "ortools/base/options.h"
+#include "ortools/gurobi/environment.h"
 #include "ortools/linear_solver/linear_solver.h"
 #include "ortools/linear_solver/linear_solver.pb.h"
 #include "ortools/linear_solver/model_exporter.h"
 #include "ortools/linear_solver/proto_solver/glop_proto_solver.h"
+#include "ortools/linear_solver/proto_solver/gurobi_proto_solver.h"
 #include "ortools/linear_solver/proto_solver/sat_proto_solver.h"
+#include "ortools/linear_solver/proto_solver/xpress_proto_solver.h"
 #include "ortools/linear_solver/solve_mp_model.h"
 #if defined(USE_SCIP)
 #include "ortools/linear_solver/proto_solver/scip_proto_solver.h"
@@ -42,6 +45,7 @@
 #include "ortools/lp_data/lp_parser.h"
 #endif  // defined(USE_LP_PARSER)
 #include "ortools/lp_data/mps_reader.h"
+#include "ortools/xpress/environment.h"
 
 namespace operations_research {
 
@@ -530,6 +534,16 @@ bool ModelSolverHelper::SolverIsSupported() const {
     return true;
   }
 #endif  // USE_SCIP
+  if (solver_type_.value() ==
+          MPModelRequest::GUROBI_MIXED_INTEGER_PROGRAMMING ||
+      solver_type_.value() == MPModelRequest::GUROBI_LINEAR_PROGRAMMING) {
+    return GurobiIsCorrectlyInstalled();
+  }
+  if (solver_type_.value() ==
+          MPModelRequest::XPRESS_MIXED_INTEGER_PROGRAMMING ||
+      solver_type_.value() == MPModelRequest::XPRESS_LINEAR_PROGRAMMING) {
+    return XpressIsCorrectlyInstalled();
+  }
   return false;
 }
 
@@ -581,6 +595,23 @@ void ModelSolverHelper::Solve(const ModelBuilderHelper& model) {
       break;
     }
 #endif  // defined(USE_PDLP)
+    case MPModelRequest::
+        GUROBI_LINEAR_PROGRAMMING:  // ABSL_FALLTHROUGH_INTENDED
+    case MPModelRequest::GUROBI_MIXED_INTEGER_PROGRAMMING: {
+      const auto temp = GurobiSolveProto(request);
+      if (temp.ok()) {
+        response_ = std::move(temp.value());
+      }
+    }
+    case MPModelRequest::
+       XPRESS_LINEAR_PROGRAMMING:  // ABSL_FALLTHROUGH_INTENDED
+    case MPModelRequest::XPRESS_MIXED_INTEGER_PROGRAMMING: {
+      const auto temp = XpressSolveProto(request);
+      if (temp.ok()) {
+        response_ = std::move(temp.value());
+      }
+    }
+
     default: {
       response_->set_status(
           MPSolverResponseStatus::MPSOLVER_SOLVER_TYPE_UNAVAILABLE);