apply code changes suggested by clang-tidy

src/ELECTRODE/fix_electrode_conp.cpp

@@ -867,7 +867,7 @@ void FixElectrodeConp::update_charges()
   accel_interface->intel_pack_buffers();
 }
 
-std::vector<double> FixElectrodeConp::ele_ele_interaction(std::vector<double> q_local)
+std::vector<double> FixElectrodeConp::ele_ele_interaction(const std::vector<double>& q_local)
 {
   assert(q_local.size() == nlocalele);
   assert(algo == Algo::CG || algo == Algo::MATRIX_CG);

src/ELECTRODE/fix_electrode_conp.h

@@ -75,7 +75,7 @@ class FixElectrodeConp : public Fix {
   virtual std::vector<double> constraint_projection(std::vector<double>);
   virtual std::vector<double> constraint_correction(std::vector<double>);
   virtual void compute_macro_matrices();
-  std::vector<double> ele_ele_interaction(std::vector<double>);
+  std::vector<double> ele_ele_interaction(const std::vector<double>&);
   std::vector<double> group_psi;
   std::vector<int> group_bits;
   std::vector<int> groups;

src/ML-POD/fitpod_command.cpp

@@ -37,6 +37,7 @@
 #include <cmath>
 #include <random>
 #include <string>
+#include <utility>
 #include <vector>
 
 using namespace LAMMPS_NS;
@@ -253,7 +254,7 @@ void FitPOD::get_exyz_files(std::vector<std::string>& files, const std::string &
 
 int FitPOD::get_number_atom_exyz(std::vector<int>& num_atom, int& num_atom_sum, std::string file)
 {
-  std::string filename = file;
+  std::string filename = std::move(file);
   FILE *fp;
   if (comm->me == 0) {
     fp = utils::open_potential(filename,lmp,nullptr);
@@ -325,7 +326,7 @@ void FitPOD::read_exyz_file(double *lattice, double *stress, double *energy, dou
     int *atomtype, std::string file, std::vector<std::string> species)
 {
 
-  std::string filename = file;
+  std::string filename = std::move(file);
   FILE *fp;
   if (comm->me == 0) {
     fp = utils::open_potential(filename,lmp,nullptr);
@@ -459,7 +460,7 @@ void FitPOD::read_exyz_file(double *lattice, double *stress, double *energy, dou
   }
 }
 
-void FitPOD::get_data(datastruct &data, std::vector<std::string> species)
+void FitPOD::get_data(datastruct &data, const std::vector<std::string>& species)
 {
   get_exyz_files(data.data_files, data.data_path, data.file_extension);
   data.num_atom_sum = get_number_atoms(data.num_atom, data.num_atom_each_file, data.num_config, data.data_files);
@@ -707,7 +708,7 @@ void FitPOD::select_data(datastruct &newdata, const datastruct &data)
                    "", maxname+90, "data_file", maxname, "", maxname+90);
   for (int i=0; i< (int) newdata.data_files.size(); i++) {
     std::string filename = newdata.data_files[i].substr(newdata.data_path.size()+1,newdata.data_files[i].size());
-    newdata.filenames.push_back(filename.c_str());
+    newdata.filenames.emplace_back(filename.c_str());
     if (comm->me == 0)
       utils::logmesg(lmp, " {:<{}} |       {:>8}       |      {:>8}      |       {:>8}       |     {:>8}\n",
                      newdata.filenames[i], maxname, newdata.num_config[i], newdata.num_atom_each_file[i],
@@ -720,7 +721,7 @@ void FitPOD::select_data(datastruct &newdata, const datastruct &data)
   }
 }
 
-void FitPOD::read_data_files(std::string data_file, std::vector<std::string> species)
+void FitPOD::read_data_files(const std::string& data_file, const std::vector<std::string>& species)
 {
   datastruct data;
 

src/ML-POD/fitpod_command.h

@@ -155,12 +155,12 @@ class FitPOD : public Command {
                        std::vector<int> &num_config, std::vector<std::string> training_files);
   void read_exyz_file(double *lattice, double *stress, double *energy, double *pos, double *forces,
                       int *atomtype, std::string file, std::vector<std::string> species);
-  void get_data(datastruct &data, std::vector<std::string> species);
+  void get_data(datastruct &data, const std::vector<std::string>& species);
   std::vector<int> linspace(int start_in, int end_in, int num_in);
   std::vector<int> shuffle(int start_in, int end_in, int num_in);
   std::vector<int> select(int n, double fraction, int randomize);
   void select_data(datastruct &newdata, const datastruct &data);
-  void read_data_files(std::string data_file, std::vector<std::string> species);
+  void read_data_files(const std::string& data_file, const std::vector<std::string>& species);
   int latticecoords(double *y, int *alist, double *x, double *a1, double *a2, double *a3,
                     double rcut, int *pbc, int nx);
   int podneighborlist(int *neighlist, int *numneigh, double *r, double rcutsq, int nx, int N,

src/REACTION/fix_bond_react.cpp

@@ -2308,7 +2308,7 @@ double FixBondReact::custom_constraint(const std::string& varstr)
   evlstr.push_back(varstr.substr(prev3+1));
 
   for (auto & evl : evlstr) evlcat += evl;
-  return input->variable->compute_equal(evlcat.c_str());
+  return input->variable->compute_equal(evlcat);
 }
 
 /* ----------------------------------------------------------------------

src/STUBS/mpi.cpp

@@ -17,10 +17,10 @@
 
 #include "../version.h"
 
-#include <stdint.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
 
 #if defined(_WIN32)
 #define WIN32_LEAN_AND_MEAN
@@ -183,7 +183,7 @@ double MPI_Wtime()
   double time;
   struct timeval tv;
 
-  gettimeofday(&tv, NULL);
+  gettimeofday(&tv, nullptr);
   time = 1.0 * tv.tv_sec + 1.0e-6 * tv.tv_usec;
   return time;
 #endif
@@ -223,7 +223,7 @@ static int stubtypesize(MPI_Datatype datatype)
 
 int MPI_Type_size(MPI_Datatype datatype, int *size)
 {
-  if (size == NULL) return MPI_ERR_ARG;
+  if (size == nullptr) return MPI_ERR_ARG;
 
   *size = stubtypesize(datatype);
   return 0;

src/info.cpp

@@ -1185,11 +1185,10 @@ bool Info::has_accelerator_feature(const std::string &package,
     }
     if (category == "api") {
 #if defined(_OPENMP)
-      if (setting == "openmp") return true;
+      return setting == "openmp";
 #else
-      if (setting == "serial") return true;
+      return setting == "serial";
 #endif
-      return false;
     }
   }
 #endif