minor fixes

ortools/linear_solver/linear_expr.cc

@@ -21,6 +21,7 @@
 #include <vector>
 
 #include "absl/strings/str_join.h"
+#include "absl/strings/string_view.h"
 #include "ortools/base/logging.h"
 #include "ortools/linear_solver/linear_solver.h"
 
@@ -87,7 +88,7 @@ double LinearExpr::SolutionValue() const {
 
 namespace {
 
-void AppendTerm(const double coef, const std::string& var_name,
+void AppendTerm(const double coef, absl::string_view var_name,
                 const bool is_first, std::string* s) {
   if (is_first) {
     if (coef == 1.0) {

ortools/linear_solver/model_exporter.cc

@@ -28,6 +28,7 @@
 #include "absl/strings/match.h"
 #include "absl/strings/str_cat.h"
 #include "absl/strings/str_format.h"
+#include "absl/strings/string_view.h"
 #include "ortools/base/commandlineflags.h"
 #include "ortools/base/logging.h"
 #include "ortools/base/map_util.h"
@@ -50,7 +51,7 @@ class LineBreaker {
   // - Lines are split so that their length doesn't exceed the max length;
   //   unless a single string given to Append() exceeds that length (in which
   //   case it will be put alone on a single unsplit line).
-  void Append(const std::string& s);
+  void Append(absl::string_view s);
 
   // Returns true if string s will fit on the current line without adding a
   // carriage return.
@@ -70,7 +71,7 @@ class LineBreaker {
   std::string output_;
 };
 
-void LineBreaker::Append(const std::string& s) {
+void LineBreaker::Append(absl::string_view s) {
   line_size_ += s.size();
   if (line_size_ > max_line_size_) {
     line_size_ = s.size();
@@ -258,15 +259,15 @@ namespace {
 class NameManager {
  public:
   NameManager() : names_set_(), last_n_(1) {}
-  std::string MakeUniqueName(const std::string& name);
+  std::string MakeUniqueName(absl::string_view name);
 
  private:
   absl::flat_hash_set<std::string> names_set_;
   int last_n_;
 };
 
-std::string NameManager::MakeUniqueName(const std::string& name) {
-  std::string result = name;
+std::string NameManager::MakeUniqueName(absl::string_view name) {
+  std::string result(name);
   // Find the 'n' so that "name_n" does not already exist.
   int n = last_n_;
   while (!names_set_.insert(result).second) {

ortools/linear_solver/wrappers/model_builder_helper.cc

@@ -215,8 +215,8 @@ void ModelBuilderHelper::SafeAddConstraintTerm(int ct_index, int var_index,
       return;
     }
   }
-  // If we reach this point, the variable does not exist in the constraint
-  // yet, so we add it to the constraint as a new term.
+  // If we reach this point, the variable does not exist in the constraint yet,
+  // so we add it to the constraint as a new term.
   ct_proto->add_var_index(var_index);
   ct_proto->add_coefficient(coeff);
 }
@@ -235,8 +235,8 @@ void ModelBuilderHelper::SetConstraintCoefficient(int ct_index, int var_index,
       return;
     }
   }
-  // If we reach this point, the variable does not exist in the constraint
-  // yet, so we add it to the constraint as a new term.
+  // If we reach this point, the variable does not exist in the constraint yet,
+  // so we add it to the constraint as a new term.
   ct_proto->add_var_index(var_index);
   ct_proto->add_coefficient(coeff);
 }
@@ -328,8 +328,8 @@ void ModelBuilderHelper::SafeAddEnforcedConstraintTerm(int ct_index,
       return;
     }
   }
-  // If we reach this point, the variable does not exist in the constraint
-  // yet, so we add it to the constraint as a new term.
+  // If we reach this point, the variable does not exist in the constraint yet,
+  // so we add it to the constraint as a new term.
   ct_proto->add_var_index(var_index);
   ct_proto->add_coefficient(coeff);
 }
@@ -352,8 +352,8 @@ void ModelBuilderHelper::SetEnforcedConstraintCoefficient(int ct_index,
       return;
     }
   }
-  // If we reach this point, the variable does not exist in the constraint
-  // yet, so we add it to the constraint as a new term.
+  // If we reach this point, the variable does not exist in the constraint yet,
+  // so we add it to the constraint as a new term.
   ct_proto->add_var_index(var_index);
   ct_proto->add_coefficient(coeff);
 }

ortools/linear_solver/xpress_interface.cc

@@ -468,7 +468,7 @@ class XpressInterface : public MPSolverInterface {
   std::vector<int> mutable initial_variables_basis_status_;
   std::vector<int> mutable initial_constraint_basis_status_;
 
-  // Set up the right-hand side of a constraint from its lower and upper bound.
+  // Setup the right-hand side of a constraint from its lower and upper bound.
   static void MakeRhs(double lb, double ub, double& rhs, char& sense,
                       double& range);
 
@@ -970,7 +970,7 @@ void XpressInterface::SetVariableInteger(int var_index, bool integer) {
   }
 }
 
-// Set up the right-hand side of a constraint.
+// Setup the right-hand side of a constraint.
 void XpressInterface::MakeRhs(double lb, double ub, double& rhs, char& sense,
                               double& range) {
   if (lb == ub) {
@@ -1366,7 +1366,7 @@ void XpressInterface::ExtractNewVariables() {
       obj[j] = solver_->objective_->GetCoefficient(var);
     }
 
-    // Arrays for modifying the problem are set up. Update the index
+    // Arrays for modifying the problem are setup. Update the index
     // of variables that will get extracted now. Updating indices
     // _before_ the actual extraction makes things much simpler in
     // case we support incremental extraction.
@@ -1416,7 +1416,7 @@ void XpressInterface::ExtractNewVariables() {
           unique_ptr<int[]> cmatind(new int[nonzeros]);
           unique_ptr<double[]> cmatval(new double[nonzeros]);
 
-          // Here is how cmatbeg[] is set up:
+          // Here is how cmatbeg[] is setup:
           // - it is initialized as
           //     [ 0, 0, collen[0], collen[0]+collen[1], ... ]
           //   so that cmatbeg[j+1] tells us where in cmatind[] and

ortools/linear_solver/xpress_interface_test.cc

@@ -741,8 +741,8 @@ TEST(XpressInterface, Write) {
 OBJSENSE  MAXIMIZE
 ROWS
  N  __OBJ___
- L  R1      
- L  R2      
+ L  R1
+ L  R2
 COLUMNS
     C1        __OBJ___  1
     C1        R1        3