[CP-SAT] revamp python implementation: introduce proper FloatLinearExpr class, move most of the expressions classes to C++

Author: lperron

ortools/sat/circuit.cc

@@ -698,9 +698,12 @@ void LoadSubcircuitConstraint(int num_nodes, const std::vector<int>& tails,
 
 std::function<void(Model*)> CircuitCovering(
     absl::Span<const std::vector<Literal>> graph,
-    const std::vector<int>& distinguished_nodes) {
-  return [=, graph = std::vector<std::vector<Literal>>(
-                 graph.begin(), graph.end())](Model* model) {
+    absl::Span<const int> distinguished_nodes) {
+  return [=,
+          distinguished_nodes = std::vector<int>(distinguished_nodes.begin(),
+                                                 distinguished_nodes.end()),
+          graph = std::vector<std::vector<Literal>>(
+              graph.begin(), graph.end())](Model* model) {
     CircuitCoveringPropagator* constraint =
         new CircuitCoveringPropagator(graph, distinguished_nodes, model);
     constraint->RegisterWith(model->GetOrCreate<GenericLiteralWatcher>());

ortools/sat/circuit.h

@@ -255,7 +255,7 @@ std::function<void(Model*)> ExactlyOnePerRowAndPerColumn(
     absl::Span<const std::vector<Literal>> graph);
 std::function<void(Model*)> CircuitCovering(
     absl::Span<const std::vector<Literal>> graph,
-    const std::vector<int>& distinguished_nodes);
+    absl::Span<const int> distinguished_nodes);
 
 }  // namespace sat
 }  // namespace operations_research

ortools/sat/python/BUILD.bazel

@@ -17,11 +17,27 @@ load("@pip_deps//:requirements.bzl", "requirement")
 load("@pybind11_bazel//:build_defs.bzl", "pybind_extension")
 load("@rules_python//python:defs.bzl", "py_library", "py_test")
 
+cc_library(
+    name = "linear_expr",
+    srcs = ["linear_expr.cc"],
+    hdrs = ["linear_expr.h"],
+    deps = [
+        "//ortools/sat:cp_model_cc_proto",
+        "//ortools/util:sorted_interval_list",
+        "@com_google_absl//absl/container:btree",
+        "@com_google_absl//absl/container:fixed_array",
+        "@com_google_absl//absl/container:flat_hash_map",
+        "@com_google_absl//absl/log:check",
+        "@com_google_absl//absl/strings",
+    ],
+)
+
 pybind_extension(
     name = "swig_helper",
     srcs = ["swig_helper.cc"],
     visibility = ["//visibility:public"],
     deps = [
+        ":linear_expr",
         "//ortools/sat:cp_model_cc_proto",
         "//ortools/sat:sat_parameters_cc_proto",
         "//ortools/sat:swig_helper",