diff --git a/src/APIP/atom_vec_apip.cpp b/src/APIP/atom_vec_apip.cpp
index f5e114deaa..d1031d8d93 100644
--- a/src/APIP/atom_vec_apip.cpp
+++ b/src/APIP/atom_vec_apip.cpp
@@ -25,9 +25,6 @@ AtomVecApip::AtomVecApip(LAMMPS *lmp) : AtomVec(lmp)
   mass_type = PER_TYPE;
   forceclearflag = 1;
 
-  double *apip_lambda, *apip_lambda_input, *apip_lambda_input_ta, *apip_lambda_const, *apip_e_fast,
-      *apip_e_precise, **apip_f_const_lambda, **apip_f_dyn_lambda;
-  int *apip_lambda_required;
   atom->apip_lambda_flag = 1;
   atom->apip_lambda_input_flag = 1;
   atom->apip_lambda_input_ta_flag = 1;
diff --git a/src/APIP/fix_atom_weight_apip.cpp b/src/APIP/fix_atom_weight_apip.cpp
index e06f983bfe..b42297e567 100644
--- a/src/APIP/fix_atom_weight_apip.cpp
+++ b/src/APIP/fix_atom_weight_apip.cpp
@@ -32,10 +32,9 @@ using namespace LAMMPS_NS;
 using namespace FixConst;
 
 FixAtomWeightAPIP::FixAtomWeightAPIP(LAMMPS *lmp, int narg, char **arg) :
-    Fix(lmp, narg, arg), fixstore(nullptr), time_simple_extract_name(nullptr),
-    time_complex_extract_name(nullptr), time_lambda_extract_name(nullptr),
-    time_group_extract_name(nullptr), time_group_name(nullptr), fix_lambda(nullptr),
-    ap_timer(nullptr)
+    Fix(lmp, narg, arg), time_simple_extract_name(nullptr), time_complex_extract_name(nullptr),
+    time_group_extract_name(nullptr), time_lambda_extract_name(nullptr), time_group_name(nullptr),
+    fixstore(nullptr), ap_timer(nullptr), fix_lambda(nullptr)
 {
   if (narg < 9) error->all(FLERR, "Illegal fix balance command");
 
@@ -119,8 +118,6 @@ FixAtomWeightAPIP::FixAtomWeightAPIP(LAMMPS *lmp, int narg, char **arg) :
   }
 
   int useless_dim = -1;
-  void *extracted_ptr = nullptr;
-
   if (time_simple_extract_name) {
     if (force->pair->extract(time_simple_extract_name, useless_dim) == nullptr)
       error->all(FLERR, "atom_weight/apip: simple time cannot be extracted with {} from {}",
diff --git a/src/APIP/fix_lambda_apip.cpp b/src/APIP/fix_lambda_apip.cpp
index 746930f77d..bdb8f8a0f7 100644
--- a/src/APIP/fix_lambda_apip.cpp
+++ b/src/APIP/fix_lambda_apip.cpp
@@ -46,9 +46,9 @@ static const char cite_fix_lambda_c[] =
 /* ---------------------------------------------------------------------- */
 
 FixLambdaAPIP::FixLambdaAPIP(LAMMPS *lmp, int narg, char **arg) :
-    Fix(lmp, narg, arg), peratom_stats(nullptr), group_name_simple(nullptr),
-    group_name_complex(nullptr), group_name_ignore_lambda_input(nullptr), fixstore(nullptr),
-    fixstore2(nullptr), pair_lambda_input(nullptr), pair_lambda_zone(nullptr)
+    Fix(lmp, narg, arg), pair_lambda_input(nullptr), pair_lambda_zone(nullptr), fixstore(nullptr),
+    fixstore2(nullptr), group_name_simple(nullptr), group_name_complex(nullptr),
+    group_name_ignore_lambda_input(nullptr), peratom_stats(nullptr)
 {
   if (lmp->citeme) lmp->citeme->add(cite_fix_lambda_c);
 
@@ -190,12 +190,14 @@ FixLambdaAPIP::FixLambdaAPIP(LAMMPS *lmp, int narg, char **arg) :
 
 int FixLambdaAPIP::modify_param(int narg, char **arg)
 {
+  if (narg < 2) utils::missing_cmd_args(FLERR, "fix_modify lambda/apip", error);
+
   cut_lo = utils::numeric(FLERR, arg[0], false, lmp);
   cut_hi = utils::numeric(FLERR, arg[1], false, lmp);
   cut_hi_sq = cut_hi * cut_hi;
   cut_width = cut_hi - cut_lo;
 
-  if (cut_lo < 0 || cut_hi < cut_lo) error->all(FLERR, "fix lambda: Illegal cutoff values");
+  if (cut_lo < 0 || cut_hi < cut_lo) error->all(FLERR, "fix lambda/apip: Illegal cutoff values");
 
   if (force->pair->cutforce < cut_hi)
     error->all(FLERR, "fix lambda: cutoff of potential smaller than cutoff of switching region");
@@ -538,21 +540,20 @@ void FixLambdaAPIP::update_lambda_history()
   if (invoked_history2_update == update->ntimestep) return;
   invoked_history2_update = update->ntimestep;
 
-  double *lambda_input_ta, **lambda_history, **lambda_input_history;
+  double *lambda_input_ta, **lambda_history;
   int *mask;
   int nlocal;
 
   lambda_input_ta = atom->apip_lambda_input_ta;
   mask = atom->mask;
   lambda_history = fixstore2->astore;
-  lambda_input_history = fixstore->astore;
   nlocal = atom->nlocal;
 
   // update stats about written values
+
   history2_last = (history2_last + 1) % history2_length;
   history2_used = std::min(history2_used + 1, history2_length);
 
-  int tmp = 0;
   for (int i = 0; i < nlocal; i++) {
     if (!(mask[i] & groupbit)) continue;
 
@@ -617,15 +618,13 @@ void FixLambdaAPIP::get_lambda_average()
 void FixLambdaAPIP::calculate_lambda_input_ta()
 {
   int i, nlocal;
-  int *mask;
   double *lambda_input_ta = atom->apip_lambda_input_ta;
 
   nlocal = atom->nlocal;
-  mask = atom->mask;
 
   // store time averaged lambda_input for own atoms
   double **lambda_input_history = fixstore->astore;
-  for (i = 0; i < nlocal; i++) { lambda_input_ta[i] = lambda_input_history[i][history_length + 1]; }
+  for (i = 0; i < nlocal; i++) lambda_input_ta[i] = lambda_input_history[i][history_length + 1];
 }
 
 /* ----------------------------------------------------------------------
@@ -740,9 +739,7 @@ void FixLambdaAPIP::write_restart(FILE *fp)
 
 void FixLambdaAPIP::restart(char *buf)
 {
-  int timesteps_since_invoked_history_update, history_length_br,
-      timesteps_since_invoked_history2_update, history2_length_br;
-  bigint next_file_write_calculated;
+  int history_length_br, history2_length_br;
 
   int n = 0;
   auto list = (double *) buf;
diff --git a/src/APIP/fix_lambda_thermostat_apip.cpp b/src/APIP/fix_lambda_thermostat_apip.cpp
index 14f94fa509..209f4969bb 100644
--- a/src/APIP/fix_lambda_thermostat_apip.cpp
+++ b/src/APIP/fix_lambda_thermostat_apip.cpp
@@ -405,15 +405,11 @@ void FixLambdaThermostatAPIP::calculate_energy_change()
 
 void FixLambdaThermostatAPIP::apply_thermostat()
 {
-  double xtmp, ytmp, ztmp, delx, dely, delz, delvx, delvy, delvz, r, dotvu, masstmp, massj, muij,
-      delv, delv_m, epsilon, epsilonsq, deltaK, rinv;
+  double xtmp, ytmp, ztmp, masstmp, massj;
   double m_cm, v_cm[3], beta_rescaling, k_rel, v_rel[3], radicand;
   int i, ii, inum, *ilist;
   int j, jj, jnum, *jlist;
 
-  int nlocal = atom->nlocal;
-  if (igroup == atom->firstgroup) nlocal = atom->nfirst;
-
   double **x = atom->x;
   double **v = atom->v;
   double *rmass = atom->rmass;
@@ -421,8 +417,6 @@ void FixLambdaThermostatAPIP::apply_thermostat()
   int *type = atom->type;
   int *mask = atom->mask;
 
-  double *e_simple = atom->apip_e_fast;
-  double *e_complex = atom->apip_e_precise;
   double *lambda_const = atom->apip_lambda_const;
   double *lambda = atom->apip_lambda;
 
@@ -465,7 +459,6 @@ void FixLambdaThermostatAPIP::apply_thermostat()
                  "particles in neighbour list particle: {} {} {} groupbit {}\n",
                  xtmp, ytmp, ztmp, mask[i] & groupbit);
 
-    int i_collisions = 0;
     double e_remain = energy_change_atom[i];
 
     // copy ngh list
diff --git a/src/APIP/pair_eam_apip.cpp b/src/APIP/pair_eam_apip.cpp
index 35c5f3769c..5cdc618f48 100644
--- a/src/APIP/pair_eam_apip.cpp
+++ b/src/APIP/pair_eam_apip.cpp
@@ -143,7 +143,7 @@ void PairEAMAPIP::compute(int eflag, int vflag)
   int n_non_complex = 0;
 
   int i, j, ii, jj, m, inum, jnum, itype, jtype;
-  double xtmp, ytmp, ztmp, delx, dely, delz, evdwl, fpair, lambda_ij, fpair_cl;
+  double xtmp, ytmp, ztmp, delx, dely, delz, evdwl, fpair, fpair_cl;
   double rsq, r, p, rhoip, rhojp, z2, z2p, recip, phip, psip, phi, psip_cl;
   double *coeff;
   int *ilist, *jlist, *numneigh, **firstneigh;
@@ -181,7 +181,6 @@ void PairEAMAPIP::compute(int eflag, int vflag)
   }
   int *type = atom->type;
   int nlocal = atom->nlocal;
-  int nall = nlocal + atom->nghost;
   int newton_pair = force->newton_pair;
 
   inum = list->inum;
diff --git a/src/APIP/pair_lambda_input_csp_apip.cpp b/src/APIP/pair_lambda_input_csp_apip.cpp
index 5f921148b3..6397975393 100644
--- a/src/APIP/pair_lambda_input_csp_apip.cpp
+++ b/src/APIP/pair_lambda_input_csp_apip.cpp
@@ -265,7 +265,7 @@ void PairLambdaInputCSPAPIP::select(int k, int n, double *arr)
 
 void PairLambdaInputCSPAPIP::select2(int k, int n, double *arr, int *iarr)
 {
-  int i, ir, j, l, mid, ia, itmp;
+  int i, ir, j, l, mid, ia;
   double a;
 
   arr--;
diff --git a/src/APIP/pair_lambda_zone_apip.cpp b/src/APIP/pair_lambda_zone_apip.cpp
index 5473f00396..2a002ede04 100644
--- a/src/APIP/pair_lambda_zone_apip.cpp
+++ b/src/APIP/pair_lambda_zone_apip.cpp
@@ -28,8 +28,7 @@ using namespace LAMMPS_NS;
 
 /* ---------------------------------------------------------------------- */
 
-PairLambdaZoneAPIP::PairLambdaZoneAPIP(LAMMPS *lmp) :
-    Pair(lmp), lambda_ta(nullptr), cut(nullptr)
+PairLambdaZoneAPIP::PairLambdaZoneAPIP(LAMMPS *lmp) : Pair(lmp), cut(nullptr), lambda_ta(nullptr)
 {
   // set defaults
 
@@ -140,7 +139,7 @@ void PairLambdaZoneAPIP::init_style()
     error->all(FLERR, "pair_lambda_zone requires an atom style with lambda_input_ta");
 
   // find fix lambda/apip
-  class Fix * fix_lambda = nullptr;
+  class Fix *fix_lambda = nullptr;
   int count = 0;
   for (int i = 0; i < modify->nfix; i++) {
     if (strcmp(modify->fix[i]->style, "lambda/apip") == 0) {
@@ -186,7 +185,7 @@ void PairLambdaZoneAPIP::calculate_lambda()
 
   double xtmp, ytmp, ztmp, delx, dely, delz, lambda_tmp, rsq, lambda_new;
   double **x, *lambda_input_ta;
-  int allnum, ii, i, nlocal, nall, jnum, j, jj, loop_iterations;
+  int allnum, ii, i, nlocal, jnum, j, jj, loop_iterations;
   int *ilist, *mask, *jlist, *numneigh, **firstneigh;
 
   mask = atom->mask;
@@ -194,7 +193,6 @@ void PairLambdaZoneAPIP::calculate_lambda()
   lambda_input_ta = atom->apip_lambda_input_ta;
 
   nlocal = atom->nlocal;
-  nall = nlocal + atom->nghost;
 
   if (nlocal > nmax_ta) {
     memory->destroy(lambda_ta);