diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1b0986a..86aa32f 100755
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,5 @@
-cmake_minimum_required (VERSION 2.6)
+CMAKE_MINIMUM_REQUIRED (VERSION 2.6)
+CMAKE_POLICY (SET CMP0011 NEW)
 
 project (NLA3D)
 
@@ -25,10 +26,14 @@ set (NLA3D_BLAS OFF
 # CMAKE_BUILD_TYPE empty or Release means the same for us
 set (CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -msse2")
 
-# TODO: this should depend on compiler
-if(UNIX) 
-    set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=gnu++11 -fPIC")
-endif()
+IF (CMAKE_CXX_COMPILER_ID STREQUAL "GNU" OR CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
+    set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -pedantic -Wno-switch")
+    set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fPIC")
+ENDIF()
+
+SET (CMAKE_CXX_STANDARD 11)
+SET (CMAKE_CXX_STANDARD_REQUIRED TRUE)
+SET (CMAKE_CXX_EXTENSION FALSE)
 
 # Linking on Mac Os was not working without this, see `cmake  --help-policy CMP0042`
 if (APPLE)
@@ -58,7 +63,7 @@ if (NLA3D_USE_MKL)
 
     find_package(MKL)
     if (MKL_FOUND)
-      include_directories(${MKL_INCLUDE_DIR})
+        include_directories(SYSTEM ${MKL_INCLUDE_DIR})
 
       # below code works fine only on UNIX systems..
       if (MKL_MULTI_THREADED)
@@ -77,14 +82,15 @@ endif() # NLA3D_USE_MKL
 
 find_package(EASYLOGGINGPP)
 if (EASYLOGGINGPP_FOUND)
-  include_directories(${EASYLOGGINGPP_INCLUDE_DIR})
+    include_directories(SYSTEM ${EASYLOGGINGPP_INCLUDE_DIR})
 else()
   message(WARNING "Can't find Easylogging++")
 endif()
 
 find_package(EIGEN)
 if (EIGEN_FOUND)
-  include_directories(${EIGEN_INCLUDE_DIR})
+    # SYSTEM for avoid warnings from the external library
+    include_directories(SYSTEM ${EIGEN_INCLUDE_DIR})
 else()
   message(WARNING "Can't find Eigen")
 endif()
diff --git a/src/FEReaders.cpp b/src/FEReaders.cpp
index 05bd890..1532e72 100644
--- a/src/FEReaders.cpp
+++ b/src/FEReaders.cpp
@@ -141,28 +141,6 @@ char sfirstNotBlank(const string& str) {
   return str[st];
 }
 
-
-std::vector<std::string> ssplit(const std::string& line, const std::vector<int>& widths, bool strict) {
-  int ind = 0;
-  vector<string> vv;
-  for (int w : widths) {
-    if (line.length() - ind < w) {
-      // no room for another field
-      if (strict) {
-        LOG(FATAL) << "ssplit: incomplete line: \"" << line << "\"";
-      } else {
-        if (line.length() - ind != 0) {
-          LOG(FATAL) << "ssplit: incomplete field: \"" << line << "\"";
-        }
-        return std::move(vv);
-      }
-    }
-    vv.push_back(line.substr(ind, w));
-    ind += w;
-  }
-  return vv;
-}
-
  
 bool iequals(const string& a, const string& b) {
     unsigned int sz = a.size();
@@ -235,9 +213,8 @@ int Tokenizer::tokenize(const string& line) {
   }
 
   if (tolower) {
-    for (int i = 0; i < tokens.size(); i++) {
-      stolower(tokens[i]);
-    }
+    for (auto& token : tokens)
+      stolower(token);
   }
   return found;
 }
@@ -254,7 +231,6 @@ double Tokenizer::tokenDouble(size_t ind) {
 
 
 bool readCdbFile(std::string filename, MeshData& md) {
-  uint32 n_number, en;
   ifstream file(filename);
   if (!file) {
     LOG(WARNING) << "Can't open cdb file " << filename;
@@ -271,11 +247,6 @@ bool readCdbFile(std::string filename, MeshData& md) {
 
   std::unordered_map<std::string, double> apdlParameters;
 
-  // current element type number. We keep the current element type number while proceed the apld
-  // file. Currently, this info is not used, but in the past it was used to determine element type
-  // while parsing EBLOCK blocks. 
-  uint32 type = 0;
-
   Tokenizer t;
   // do not convert tokens to lower symbols
   t.tolower = false;
@@ -311,27 +282,17 @@ bool readCdbFile(std::string filename, MeshData& md) {
       stolower(strim(line));
       std::regex re(R"(\((\d+)i(\d+),(\d+)e(\d+)\.[0-9e]+\))");
       std::smatch match;
-      int int_num;
-      int int_field;
-      int float_num;
-      int float_field;
-      if (std::regex_match(line, match, re)) {
-        int_num = std::stoi(match[1]);
-        int_field = std::stoi(match[2]);
-        float_num = std::stoi(match[3]);
-        float_field = std::stoi(match[4]);
-      } else {
+      if (!std::regex_match(line, match, re)) {
         LOG(FATAL) << "Don't understand nblock format string \"" << line << "\"";
       }
+      size_t const int_num = std::stoi(match[1]);
+      size_t const int_field = std::stoi(match[2]);
+      size_t const float_num = std::stoi(match[3]);
+      size_t const float_field = std::stoi(match[4]);
 
       // prepare array of field widths
-      std::vector<int> widths;
-      for (int i = 0; i < int_num; i++) {
-        widths.push_back(int_field);
-      }
-      for (int i = 0; i < float_num; i++) {
-        widths.push_back(float_field);
-      }
+      std::vector<size_t> widths(int_num, int_field);;
+      widths.insert(widths.end(), float_num, float_field);
 
       // read nodes info line by line
       while(!getLine(file, line).eof()) {
@@ -390,20 +351,14 @@ bool readCdbFile(std::string filename, MeshData& md) {
       stolower(strim(line));
       std::regex re(R"(\((\d+)i(\d+)\))");
       std::smatch match;
-      int int_num;
-      int int_field;
-      if (std::regex_match(line, match, re)) {
-        int_num = std::stoi(match[1]);
-        int_field = std::stoi(match[2]);
-      } else {
+      if (!std::regex_match(line, match, re)) {
         LOG(FATAL) << "Don't understand eblock format string \"" << line << "\"";
       }
+      size_t const int_num = std::stoi(match[1]);
+      size_t const int_field = std::stoi(match[2]);
 
       // prepare array of field widths
-      std::vector<int> widths;
-      for (int i = 0; i < int_num; i++) {
-        widths.push_back(int_field);
-      }
+      std::vector<size_t> widths(int_num, int_field);
       // read element data line by line
       while(!getLine(file, line).eof()) {
         // check for the end of element table
@@ -450,7 +405,7 @@ bool readCdbFile(std::string filename, MeshData& md) {
           LOG(FATAL) << "Not enought fields to read element nodes";
         }
         // parse element nodes
-        for (int i = 0; i < nNodes; i++) {
+        for (uint32 i = 0; i < nNodes; i++) {
           enodes.push_back(static_cast<uint32>(std::stoi(v[st + i])));
         }
 
@@ -495,7 +450,6 @@ bool readCdbFile(std::string filename, MeshData& md) {
       while (n_terms > 0) {
         getLine(file, line);
         t.tokenize(line);
-        uint16 place = 6;
         for (int i = 0; i < std::max(n_terms, 2); i++) {
           uint32 node = t.tokenInt(3 + 3 * i + 0);
           Dof::dofType dof = Dof::label2dofType(t.tokens[3 + 3 * i + 1]);
@@ -527,19 +481,13 @@ bool readCdbFile(std::string filename, MeshData& md) {
         stolower(strim(line));
         std::regex re(R"(\((\d+)i(\d+)\))");
         std::smatch match;
-        int int_num;
-        int int_field;
-        if (std::regex_match(line, match, re)) {
-          int_num = std::stoi(match[1]);
-          int_field = std::stoi(match[2]);
-        } else {
+        if (!std::regex_match(line, match, re)) {
           LOG(FATAL) << "Don't understand CMBLOCK format string \"" << line << "\"";
         }
+        size_t const int_num = std::stoi(match[1]);
+        size_t const int_field = std::stoi(match[2]);
         // prepare array of field widths
-        std::vector<int> widths;
-        for (int i = 0; i < int_num; i++) {
-          widths.push_back(int_field);
-        }
+        std::vector<size_t> widths(int_num, int_field);;
 
         uint16 in_row = 0;
         uint16 all = 0;
@@ -586,29 +534,6 @@ bool readCdbFile(std::string filename, MeshData& md) {
         md.feComps.insert(std::make_pair(comp.name, comp));
       }
     } //CMBLOCK
-    else if (iequals(t.tokens[0], "ET") || iequals(t.tokens[0], "ETYPE")) {
-      // Keep a track on last ET command.. We need this info to know element type.
-      // If we can convert ET argument into int, then we try to find the APDL parameter in
-      // apdlParameters dictionary. If it's not there - adpParameters will return new zero value.
-      // That means, that if parameter is not declared(somehow..) we just put type = 0
-      // NOTE: in current implementation type value is not used, but it could be used again in the
-      // future.
-      try {
-        type = t.tokenInt(1);
-      } catch (const std::invalid_argument& ia) {
-        type = static_cast<uint32>(apdlParameters[t.tokens[1]]);
-      }
-    } // ETYPE
-    else if (iequals(t.tokens[0], "TYPE")) {
-      // Keep the track on last TYPE command.. We need this info to know element type.
-      // NOTE: in current implementation type value is not used, but it could be used again in the
-      // future.
-      try {
-        type = t.tokenInt(1);
-      } catch (const std::invalid_argument& ia) {
-        type = 0;
-      }
-    } // ETYPE
     else if (iequals(t.tokens[0], "F")) {
       // Dof force record
       //f,42,heat,800000.
diff --git a/src/FEReaders.h b/src/FEReaders.h
index 0e07f3c..d5ae0cb 100644
--- a/src/FEReaders.h
+++ b/src/FEReaders.h
@@ -67,8 +67,28 @@ std::string& stoupper(std::string& str);
 
 // split `line` to substrings with `widths` lengths, if `strict` is false then last substrings could
 // be missed
-std::vector<std::string> ssplit(const std::string& line, const std::vector<int>& widths,
-                                  bool strict = true);
+template<typename CONT>
+std::vector<std::string> ssplit(std::string const& line, CONT const& widths, bool strict = true) {
+  size_t ind = 0;
+  std::vector<std::string> vv;
+  for (auto const& w : widths) {
+    if (line.length() < w + ind) {
+      // no room for another field
+      if (strict) {
+        LOG(FATAL) << "ssplit: incomplete line: \"" << line << "\"";
+      } else {
+        if (line.length() - ind != 0) {
+          LOG(FATAL) << "ssplit: incomplete field: \"" << line << "\"";
+        }
+        return vv;
+      }
+    }
+    vv.push_back(line.substr(ind, w));
+    ind += w;
+  }
+  return vv;
+}
+
 
 // case insensitive string comparison
 bool iequals(const string& a, const string& b);
diff --git a/src/lib/FESolver.cpp b/src/lib/FESolver.cpp
index 148e005..9ac800f 100644
--- a/src/lib/FESolver.cpp
+++ b/src/lib/FESolver.cpp
@@ -130,10 +130,11 @@ FESolver::~FESolver() {
 
 
 void FESolver::attachFEStorage(FEStorage *st) {
+  CHECK_NOTNULL(st);
   if (storage) {
     LOG(WARNING) << "FEStorage already is attached. The old one will be dropped.";
   }
-  storage = CHECK_NOTNULL(st);
+  storage = st;
 }
 
 
@@ -166,10 +167,11 @@ void FESolver::deletePostProcessors() {
 
 
 void FESolver::attachEquationSolver(math::EquationSolver *eq) {
+  CHECK_NOTNULL(eq);
   if (eqSolver) {
     LOG(WARNING) << "EquationSolver already is attached. The old one will be dropped.";
   }
-  eqSolver = CHECK_NOTNULL(eq);
+  eqSolver = eq;
 }
 
 void FESolver::initSolutionData() {
diff --git a/src/lib/FEStorage.cpp b/src/lib/FEStorage.cpp
index 211a983..9d4ebd8 100644
--- a/src/lib/FEStorage.cpp
+++ b/src/lib/FEStorage.cpp
@@ -9,10 +9,6 @@ namespace nla3d {
 using namespace math;
 
 
-FEStorage::FEStorage()  {
-};
-
-
 FEStorage::~FEStorage () {
 	if (material) {
     delete material;
@@ -533,7 +529,6 @@ void FEStorage::initSolutionData () {
   // register MPC coefficients
   for (auto mpc : mpcs) {
     assert(mpc->eq.size());
-    uint32 eq_num = mpc->eqNum;
     for (auto term : mpc->eq) {
     uint32 eq_j = getNodeDofEqNumber(term.node, term.node_dof);
       addEntryMPC(mpc->eqNum, eq_j);
diff --git a/src/lib/FEStorage.h b/src/lib/FEStorage.h
index 79f23f1..bc9bb2f 100755
--- a/src/lib/FEStorage.h
+++ b/src/lib/FEStorage.h
@@ -37,7 +37,6 @@ class ElementFactory;
 // should start from 1 and up to nElements()/nNodes().
 class FEStorage {
 public:
-	FEStorage();
 	~FEStorage();
 
   // A pointer to Material instance. nla3d supports only one material for FE model.  External code
diff --git a/src/lib/Mpc.cpp b/src/lib/Mpc.cpp
index 2d48436..c0674cc 100644
--- a/src/lib/Mpc.cpp
+++ b/src/lib/Mpc.cpp
@@ -41,10 +41,6 @@ void MpcCollection::printEquations (std::ostream& out) {
   }
 }
 
-RigidBodyMpc::RigidBodyMpc () {
-
-}
-
 RigidBodyMpc::~RigidBodyMpc () {
   collection.clear();
 }
@@ -120,7 +116,7 @@ void RigidBodyMpc::update () {
     // drivatives for C matrix for i row (with respect to j and l)
     Mat<3,3> cDeriv;
     for (size_t d = 0; d < dofs.size(); d++) {
-      uint16 i;
+      uint16 i = 0;
       switch (dofs[d]) {
         case Dof::UX:
           i = 0;
diff --git a/src/lib/Mpc.h b/src/lib/Mpc.h
index 22c4a5b..cc2e09c 100644
--- a/src/lib/Mpc.h
+++ b/src/lib/Mpc.h
@@ -39,6 +39,7 @@ class Mpc {
 
 class MpcCollection {
   public:
+    virtual ~MpcCollection() { }
     virtual void update() = 0;
     virtual void pre() = 0;
     void printEquations(std::ostream& out);
@@ -50,9 +51,8 @@ class MpcCollection {
 
 class RigidBodyMpc : public MpcCollection {
   public:
-    RigidBodyMpc();
     ~RigidBodyMpc();
-    uint32 masterNode;
+    uint32 masterNode = 0;
 
     void pre ();
     void update ();
@@ -74,8 +74,7 @@ class fixBC {
 
 class loadBC {
 public:
-  loadBC () : node(0), node_dof(Dof::UNDEFINED), value(0.0)
-  { }
+  loadBC () { }
   loadBC (int32 n, Dof::dofType dof, double val = 0.0) : node(n), node_dof(dof), value(val)
   { }
   int32 node = 0;
diff --git a/src/lib/PostProcessor.h b/src/lib/PostProcessor.h
index 3ad5b30..0add1cc 100755
--- a/src/lib/PostProcessor.h
+++ b/src/lib/PostProcessor.h
@@ -15,7 +15,7 @@ class FESolver;
 class PostProcessor {
 public:
 	PostProcessor(FEStorage *st);
-	~PostProcessor() { };
+	virtual ~PostProcessor() { };
 	virtual void pre ()=0;
 	virtual void process (uint16 curLoadstep)=0;
 	virtual void post (uint16 curLoadstep)=0;
diff --git a/src/lib/VtkProcessor.cpp b/src/lib/VtkProcessor.cpp
index 4dacf72..351bff4 100755
--- a/src/lib/VtkProcessor.cpp
+++ b/src/lib/VtkProcessor.cpp
@@ -75,10 +75,12 @@ void VtkProcessor::writeAllResults(bool write) {
 
 
 bool VtkProcessor::registerResults(std::initializer_list<scalarQuery> queries) {
+#if not defined (NDEBUG)
   // check that each query is valid
-  for(auto v : queries) {
+  for(auto const& v : queries) {
     assert(v > scalarQuery::UNDEF && v < scalarQuery::LAST);
   }
+#endif
 
   cellScalarQueries.insert(queries);
   return true;
@@ -86,10 +88,12 @@ bool VtkProcessor::registerResults(std::initializer_list<scalarQuery> queries) {
 
 
 bool VtkProcessor::registerResults(std::initializer_list<vectorQuery> queries) {
+#if not defined (NDEBUG)
   // check that each query is valid
-  for(auto v : queries) {
+  for(auto const& v : queries) {
     assert(v > vectorQuery::UNDEF && v < vectorQuery::LAST);
   }
+#endif
 
   cellVectorQueries.insert(queries);
   return true;
@@ -97,10 +101,12 @@ bool VtkProcessor::registerResults(std::initializer_list<vectorQuery> queries) {
 
 
 bool VtkProcessor::registerResults(std::initializer_list<tensorQuery> queries) {
+#if not defined (NDEBUG)
   // check that each query is valid
-  for(auto v : queries) {
+  for(auto const& v : queries) {
     assert(v > tensorQuery::UNDEF && v < tensorQuery::LAST);
   }
+#endif
 
   cellTensorQueries.insert(queries);
   return true;
diff --git a/src/lib/elements/SOLID81.cpp b/src/lib/elements/SOLID81.cpp
index a3130f4..fe72674 100644
--- a/src/lib/elements/SOLID81.cpp
+++ b/src/lib/elements/SOLID81.cpp
@@ -34,7 +34,8 @@ void ElementSOLID81::buildK() {
   Vec<24> Kup;
   Vec<24> Fu; //вектор узловых сил элемента
   Vec<24> F_ext; //вектор внешних сил (пока не подсчитывается)
-  Mat_Hyper_Isotrop_General* mat = CHECK_NOTNULL( dynamic_cast<Mat_Hyper_Isotrop_General*> (storage->getMaterial()));
+  Mat_Hyper_Isotrop_General* mat = dynamic_cast<Mat_Hyper_Isotrop_General*> (storage->getMaterial());
+  CHECK_NOTNULL(mat);
   double k = mat->getK();
   MatSym<6> matD_d;
   Vec<6> vecD_p;
@@ -95,7 +96,8 @@ void ElementSOLID81::update()
   Vec<6> vecC;
   double p_e = storage->getElementDofSolution(getElNum(), Dof::HYDRO_PRESSURE);
 
-  Mat_Hyper_Isotrop_General* mat = CHECK_NOTNULL(dynamic_cast<Mat_Hyper_Isotrop_General*> (storage->getMaterial()));
+  Mat_Hyper_Isotrop_General* mat = dynamic_cast<Mat_Hyper_Isotrop_General*> (storage->getMaterial());
+  CHECK_NOTNULL(mat);
   for (uint16 np = 0; np < nOfIntPoints(); np++) {
     B_NL.zero();
     make_B_NL(np, B_NL);
@@ -217,13 +219,15 @@ bool ElementSOLID81::getScalar(double* scalar, scalarQuery query, uint16 gp, con
 
     case scalarQuery::WU:
       getVector(&tmp, vectorQuery::IC, gp, 1.0);
-      mat = CHECK_NOTNULL(dynamic_cast<Mat_Hyper_Isotrop_General*>(storage->getMaterial()));
+      mat = dynamic_cast<Mat_Hyper_Isotrop_General*>(storage->getMaterial());
+      CHECK_NOTNULL(mat);
       *scalar += mat->W(tmp[0], tmp[1], tmp[2]) * scale;
       return true;
 
     case scalarQuery::WP:
       J = solidmech::J_C(C[gp].ptr());
-      mat = CHECK_NOTNULL(dynamic_cast<Mat_Hyper_Isotrop_General*>(storage->getMaterial()));
+      mat = dynamic_cast<Mat_Hyper_Isotrop_General*>(storage->getMaterial());
+      CHECK_NOTNULL(mat);
       *scalar += 0.5 * mat->getK() * (J - 1.0) * (J - 1.0) * scale;
       return true;
 
diff --git a/src/lib/elements/isoparametric.cpp b/src/lib/elements/isoparametric.cpp
index 5c527e3..1368982 100644
--- a/src/lib/elements/isoparametric.cpp
+++ b/src/lib/elements/isoparametric.cpp
@@ -11,9 +11,6 @@ namespace nla3d {
 
 
 void ElementIsoParamLINE::makeJacob() {
-  const uint16 dim = 2;
-  const uint16 nodes_num = 4;
-
   // bound user-provided intOrder
   intOrder = (intOrder < 1) ? 1 : intOrder;
   intOrder = (intOrder > 3) ? 3 : intOrder;
@@ -71,8 +68,6 @@ void ElementIsoParamQUAD::makeJacob() {
   NiXj.clear();
   NiXj.resize(_np_quad[i_int]);
 
-  double inv_det;
-
   math::Mat<nodes_num, dim> dN; // form function derivatives
   math::Mat<dim, dim> J;
 
@@ -94,7 +89,6 @@ void ElementIsoParamQUAD::makeJacob() {
     // check for geometry form error 
     LOG_IF(det[np] < 1.0e-20, ERROR) << "Determinant is too small (" << det[np] << ") in element = " << elNum;
     // обращение матрицы Якоби
-    inv_det = 1.0/det[np];
     Jacob = J.inv(det[np]);
 
     // производные функций формы по глоб. координатам
@@ -154,8 +148,6 @@ void ElementIsoParamHEXAHEDRON::makeJacob() {
   NiXj.clear();
   NiXj.resize(_np_hexahedron[i_int]);
 
-  double inv_det;
-
   math::Mat<nodes_num, dim> dN; // form function derivatives
   math::Mat<dim, dim> J;
 
@@ -176,7 +168,6 @@ void ElementIsoParamHEXAHEDRON::makeJacob() {
     // check for geometry form error 
     LOG_IF(det[np] < 1.0e-20, ERROR) << "Determinant is too small (" << det[np] << ") in element = " << elNum;
     // обращение матрицы Якоби
-    inv_det = 1.0/det[np];
     Jacob = J.inv(det[np]);
 
     // производные функций формы по глоб. координатам
diff --git a/src/lib/materials/material.cpp b/src/lib/materials/material.cpp
index bf31414..080db88 100755
--- a/src/lib/materials/material.cpp
+++ b/src/lib/materials/material.cpp
@@ -28,14 +28,15 @@ std::string Material::toString() {
 }
 
 double& Material::Ci (const std::string& nameConst) {
-  for (size_t i = 0; i < getNumC(); i++) {
+  size_t i = 0;
+  for (; i < getNumC(); i++) {
     if (nameConst.compare(MC_names[i]) == 0) {
-      return MC[i];
+      break;
     }
   }
-	LOG(ERROR) << "Dan't find a material constant with name " << nameConst;
-  double dummy;
-  return dummy;
+  if (i == getNumC())
+    LOG(ERROR) << "Can't find a material constant with name " << nameConst;
+  return MC[i];
 }
 
 
diff --git a/src/lib/materials/material.h b/src/lib/materials/material.h
index c8b0d00..c96e2d5 100755
--- a/src/lib/materials/material.h
+++ b/src/lib/materials/material.h
@@ -14,10 +14,9 @@ class MaterialFactory;
 // Material must have named material constants
 class Material {
 public:
-	Material () : MC(NULL), numC(0), code(0) { 
-	}
+    Material() { }
 	Material (uint16 num_c);
-	~Material()   // TODO: discover the virtual destructor
+	virtual ~Material()
 	{
 		if (MC) delete[] MC; 
 		MC = NULL;
@@ -37,10 +36,10 @@ class Material {
   friend class MaterialFactory;
 protected:
 	void register_mat_const(uint16 num, ...);
-	double* MC;
+	double* MC = nullptr;
 	std::vector<std::string> MC_names;
-	uint16 numC;
-	uint16 code;
+	uint16 numC = 0;
+	uint16 code = 0;
 	std::string name;
 };
 
diff --git a/src/lib/materials/materials_hyperelastic.cpp b/src/lib/materials/materials_hyperelastic.cpp
index 443ee8a..b648682 100644
--- a/src/lib/materials/materials_hyperelastic.cpp
+++ b/src/lib/materials/materials_hyperelastic.cpp
@@ -38,7 +38,6 @@ void Mat_Hyper_Isotrop_General::getS_UP (uint16 ncomp, const  solidmech::tensorC
 	
 	double J = IC[2];
 	
-	double oo = 1.0/(J*J);
 	double pp = pow(J,-2.0/3.0);
 	double pppp = pp*pp;
 	
diff --git a/src/lib/math/EquationSolver.cpp b/src/lib/math/EquationSolver.cpp
index d0e8e43..bd3cfce 100644
--- a/src/lib/math/EquationSolver.cpp
+++ b/src/lib/math/EquationSolver.cpp
@@ -74,6 +74,7 @@ bool GaussDenseEquationSolver::_solve(double* X, double* A,
         // We are trying eliminate the term in column i, for rows i+1 and
         // greater. First, find a pivot (between rows i and N-1).
         max = 0;
+        imax = i;
         for(ip = i; ip < n; ip++) {
           //if(ffabs(A[ip][i]) > max) {
             if(fabs(A[ip*n+i]) > max) {
diff --git a/src/lib/math/Mat.h b/src/lib/math/Mat.h
index cbb128e..606d5f4 100755
--- a/src/lib/math/Mat.h
+++ b/src/lib/math/Mat.h
@@ -401,8 +401,6 @@ class dMat;
 class dMat_interface
 {
 public:
-	dMat_interface ():ptr(NULL),M(0),N(0),row(0) 
-	{	}
 	double& operator[] (uint16 col)
 	{
 		assert(ptr);
@@ -410,18 +408,26 @@ class dMat_interface
 		assert (row < M);
 		return ptr[row*N + col];
 	}
+	double operator[] (uint16 col) const
+	{
+		assert(ptr);
+		assert (col < N);
+		assert (row < M);
+		return ptr[row*N + col];
+	}
 	friend class dMat;
 private:
-	uint16 M, N;
-	uint32 row;
-	double *ptr;
+	uint16 M = 0;
+	uint16 N = 0;
+	uint32 row = 0;
+	double *ptr = nullptr;
 };
 
 //dynamic matrix to pass arbitrary matrix to functions as arguments
 class dMat
 {
 public:
-	dMat(uint16 dim_m, uint16 dim_n) : dimM(0),dimN(0),data(NULL)
+	dMat(uint16 dim_m, uint16 dim_n)
 	{
 		if (dim_m && dim_n)
 			resize(dim_m, dim_n);
@@ -470,7 +476,7 @@ class dMat
 	~dMat()
 	{
 		if (data) delete[] data;
-		data = NULL;
+		data = nullptr;
 	}
 
 	void zero ()
@@ -504,9 +510,9 @@ class dMat
 
 	friend std::ostream& operator<< (std::ostream& stream, dMat &obj);
 private:
-	uint16 dimM;
-	uint16 dimN;
-	double *data;
+	uint16 dimM = 0;
+	uint16 dimN = 0;
+	double *data = nullptr;
 	dMat_interface dmat_int;
 };
 
diff --git a/src/lib/math/SparseMatrix.cpp b/src/lib/math/SparseMatrix.cpp
index bf851ff..d955ccd 100755
--- a/src/lib/math/SparseMatrix.cpp
+++ b/src/lib/math/SparseMatrix.cpp
@@ -381,7 +381,6 @@ void SparseMatrix::print(std::ostream& out) {
   assert(si->compressed);
   assert(values);
 
-	uint32 ind;
 	for (uint32 i = 1; i <= si->nRows; i++) {
 		out << "[";
 		for (uint32 j = 1; j <= si->nColumns; j++) {
@@ -453,7 +452,6 @@ void SparseSymMatrix::print(std::ostream& out) {
   assert(si->compressed);
   assert(values);
 
-	uint32 ind;
 	for (uint32 i = 1; i <= si->nRows; i++) {
 		// out << "[";
 		for (uint32 j = 1; j <= si->nColumns; j++) {
diff --git a/src/lib/sys.h b/src/lib/sys.h
index cdabc52..4d63a12 100755
--- a/src/lib/sys.h
+++ b/src/lib/sys.h
@@ -10,7 +10,6 @@
 #include <string>
 #include <iostream>
 #include <fstream>
-#include <strstream>
 #include <stdarg.h>
 #include <assert.h>
 #include <time.h>
@@ -40,11 +39,6 @@
   #define sprintf_s snprintf
 #endif
 
-// TODO:
-// for some reasons CHECK_NOTNULL from easylogging++ doesn't work on Apple's clang and g++
-#undef CHECK_NOTNULL
-#define CHECK_NOTNULL(x) x
-
 // usefull macros to check floats with threshold
 #define CHECK_EQTH(a, b, th) CHECK(fabs(a-b) < th)
 
diff --git a/src/main.cpp b/src/main.cpp
index 1bd3758..8ef0907 100755
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -34,7 +34,7 @@ namespace options {
   uint32 rigidBodyMasterNode = 0;
   std::string rigidBodySlavesComponent = "";
   std::vector<Dof::dofType> rigidBodyDofs;
-};
+}
 
 bool parse_args (int argc, char* argv[]) {
   if (argc < 2) {
@@ -170,7 +170,8 @@ int main (int argc, char* argv[]) {
   }
   md.compressNumbers();
 
-  Material* mat = CHECK_NOTNULL (MaterialFactory::createMaterial(options::materialName));
+  Material* mat = MaterialFactory::createMaterial(options::materialName);
+  CHECK_NOTNULL(mat);
   if (mat->getNumC() != options::materialConstants.size())
     LOG(ERROR) << "Material " << options::materialName << " needs exactly " << mat->getNumC()
       << " constants (" << options::materialConstants.size() << " were provided)";
@@ -298,7 +299,7 @@ int main (int argc, char* argv[]) {
       ss << '\t' << Dof::dofTypeLabels[reactProc->dofs[d]];
     }
     ss << std::endl;
-    for (size_t ls = 0; ls < options::numberOfLoadsteps+1; ls++) {
+    for (uint16 ls = 0; ls < options::numberOfLoadsteps+1; ls++) {
       ss << ls;
       for (size_t d = 0; d < reactProc->dofs.size(); d++) {
         ss << '\t' << reactProc->getReactions(reactProc->dofs[d])[ls];
diff --git a/test/QUADTH_transient.cpp b/test/QUADTH_transient.cpp
index df8e152..15dd6ed 100644
--- a/test/QUADTH_transient.cpp
+++ b/test/QUADTH_transient.cpp
@@ -186,7 +186,6 @@ std::vector<double> readTempData (std::string fileRefCurve) {
   if (!file.is_open()) {
     return res;
   }
-  double tmp;
   std::string line;
   // skip first line
   getLine(file, line);
diff --git a/test/TETRA0_test.cpp b/test/TETRA0_test.cpp
index 0a4fdaf..e425862 100644
--- a/test/TETRA0_test.cpp
+++ b/test/TETRA0_test.cpp
@@ -141,7 +141,7 @@ stress_vec_t readStressData (std::string filename) {
     if (!file.is_open()) {
         return stress_vec;
     }
-    double tmp, sx, sy, sz, sxy, syz, sxz;
+    double tmp;
     // file format:
     //    elem SX   SY   SZ   SXY  SYZ  SXZ
     //          1.  0.28688422E+02  0.90668364E+01  0.11326577E+02  0.65410609E-01 -0.36082213E+01 -0.19945953E+01