diff --git a/libsrc/core/.clang-tidy b/libsrc/core/.clang-tidy
index 5742a3d8..9ceddce8 100644
--- a/libsrc/core/.clang-tidy
+++ b/libsrc/core/.clang-tidy
@@ -1,5 +1,8 @@
-Checks: '*,-clang-analyzer-alpha.*,-*braces-around-statements,-fuchsia-*,-google-runtime-references,-readability-implicit-bool-conversion,-google-explicit-constructor,-hicpp-explicit-conversions,-google-runtime-int,-llvm-header-guard,-modernize-pass-by-value'
+Checks: '*,-clang-analyzer-alpha.*,-*braces-around-statements,-fuchsia-*,-google-runtime-references,-readability-implicit-bool-conversion,-google-explicit-constructor,-hicpp-explicit-conversions,-google-runtime-int,-llvm-header-guard,-modernize-pass-by-value,-cppcoreguidelines-non-private-member-variables-in-classes,-misc-non-private-member-variables-in-classes,-readability-magic-numbers,-cppcoreguidelines-avoid-magic-numbers'
 CheckOptions:
         - key: cppcoreguidelines-special-member-functions.AllowSoleDefaultDtor
           value: 1
+        - key: cppcoreguidelines-macro-usage.AllowedRegexp
+          value: NGCORE_*|NETGEN_*|NG_EXCEPTION*
+
 WarningsAsErrors: '*'
diff --git a/libsrc/core/archive.hpp b/libsrc/core/archive.hpp
index 4dfa6628..c708c596 100644
--- a/libsrc/core/archive.hpp
+++ b/libsrc/core/archive.hpp
@@ -1,6 +1,7 @@
 #ifndef NETGEN_CORE_ARCHIVE_HPP
 #define NETGEN_CORE_ARCHIVE_HPP
 
+#include <array>                // for array
 #include <complex>              // for complex
 #include <cstring>              // for size_t, strlen
 #include <fstream>              // for ifstream, ofstream
@@ -657,7 +658,7 @@ namespace ngcore
   class NGCORE_API BinaryOutArchive : public Archive
   {
     static constexpr size_t BUFFERSIZE = 1024;
-    char buffer[BUFFERSIZE] = {};
+    std::array<char,BUFFERSIZE> buffer{};
     size_t ptr = 0;
   protected:
     std::shared_ptr<std::ostream> stream;
@@ -701,7 +702,7 @@ namespace ngcore
     }
     Archive & operator & (char *& str) override
     {
-      long len = str ? strlen (str) : -1;
+      long len = str ? static_cast<long>(strlen (str)) : -1;
       (*this) & len;
       FlushBuffer();
       if(len > 0)
@@ -838,7 +839,7 @@ namespace ngcore
     }
     Archive & operator & (char *& str) override
     {
-      long len = str ? strlen (str) : -1;
+      long len = str ? static_cast<long>(strlen (str)) : -1;
       *this & len;
       if(len > 0)
         {
@@ -994,7 +995,7 @@ namespace ngcore
                                                     std::string(pybind11::str(output)));
                         return output;
                       },
-                      [](pybind11::tuple state)
+                      [](const pybind11::tuple & state)
                       {
                         T* val = nullptr;
                         GetLogger("Archive")->trace("State for unpickling of object of type {} = {}",
diff --git a/libsrc/core/paje_trace.cpp b/libsrc/core/paje_trace.cpp
index 66a3b8a1..f9c5ba89 100644
--- a/libsrc/core/paje_trace.cpp
+++ b/libsrc/core/paje_trace.cpp
@@ -98,7 +98,7 @@ namespace ngcore
           // return time in milliseconds as double
         // return std::chrono::duration<double>(t-start_time).count()*1000.0;
         // return std::chrono::duration<double>(t-start_time).count() / 2.7e3;
-        return 1000.0*(t-start_time) / ticks_per_second;
+        return 1000.0*static_cast<double>(t-start_time) / ticks_per_second;
       }
 
       enum PType
@@ -241,7 +241,9 @@ namespace ngcore
             }
 
           int alias = ++alias_counter;
-          double r,g,b;
+          double r;
+          double g;
+          double b;
           Hue2RGB( hue, r, g, b );
           fprintf( ctrace_stream, "%d\ta%d\ta%d\t\"%s\"\t\"%.15g %.15g %.15g\"\n", PajeDefineEntityValue, alias, type, name.c_str(), r,g,b ); // NOLINT
           return alias;
@@ -346,7 +348,7 @@ namespace ngcore
 
   void PajeTrace::Write( const std::string & filename )
     {
-      int n_events = jobs.size() + timer_events.size();
+      auto n_events = jobs.size() + timer_events.size();
       for(auto & vtasks : tasks)
         n_events += vtasks.size();
 
@@ -558,11 +560,11 @@ namespace ngcore
   // Write HTML file drawing a sunburst chart with cumulated timings
   struct TreeNode
   {
-      int id;
+      int id = 0;
       std::map<int, TreeNode> children;
-      double time;
+      double time = 0.0;
       std::string name;
-      TTimePoint start_time;
+      TTimePoint start_time = 0;
   };
 
   void PrintNode (const TreeNode &n, int &level, std::ofstream & f);
@@ -627,7 +629,7 @@ namespace ngcore
 
       std::sort (events.begin(), events.end());
 
-      root.time = 1000.0*(stop_time-start_time)/ticks_per_second;
+      root.time = 1000.0*static_cast<double>(stop_time-start_time)/ticks_per_second;
 
       for(auto & event : events)
       {
@@ -652,7 +654,7 @@ namespace ngcore
           }
           else
           {
-              double time = 1000.0*(event.time-current->start_time)/ticks_per_second;
+              double time = 1000.0*static_cast<double>(event.time-current->start_time)/ticks_per_second;
               current->time += time;
               current = node_stack.back();
               current->time -= time;
diff --git a/libsrc/core/profiler.cpp b/libsrc/core/profiler.cpp
index 3302342d..1190e6fe 100644
--- a/libsrc/core/profiler.cpp
+++ b/libsrc/core/profiler.cpp
@@ -8,10 +8,10 @@ namespace ngcore
 
   std::string NgProfiler::filename;
 
-  size_t NgProfiler::dummy_thread_times[NgProfiler::SIZE];
-  size_t * NgProfiler::thread_times = NgProfiler::dummy_thread_times; // NOLINT
-  size_t NgProfiler::dummy_thread_flops[NgProfiler::SIZE];
-  size_t * NgProfiler::thread_flops = NgProfiler::dummy_thread_flops; // NOLINT
+  std::array<size_t,NgProfiler::SIZE> NgProfiler::dummy_thread_times;
+  size_t * NgProfiler::thread_times = NgProfiler::dummy_thread_times.data(); // NOLINT
+  std::array<size_t,NgProfiler::SIZE> NgProfiler::dummy_thread_flops;
+  size_t * NgProfiler::thread_flops = NgProfiler::dummy_thread_flops.data(); // NOLINT
 
   std::shared_ptr<Logger> NgProfiler::logger = GetLogger("Profiler"); // NOLINT
 
diff --git a/libsrc/core/profiler.hpp b/libsrc/core/profiler.hpp
index 5a9b16e1..4e4b565c 100644
--- a/libsrc/core/profiler.hpp
+++ b/libsrc/core/profiler.hpp
@@ -1,6 +1,7 @@
 #ifndef NETGEN_CORE_PROFILER_HPP
 #define NETGEN_CORE_PROFILER_HPP
 
+#include <array>
 #include <chrono>
 #include <string>
 
@@ -35,8 +36,8 @@ namespace ngcore
     NGCORE_API static TTimePoint * thread_times;
     NGCORE_API static TTimePoint * thread_flops;
     NGCORE_API static std::shared_ptr<Logger> logger;
-    NGCORE_API static size_t dummy_thread_times[NgProfiler::SIZE];
-    NGCORE_API static size_t dummy_thread_flops[NgProfiler::SIZE];
+    NGCORE_API static std::array<size_t, NgProfiler::SIZE> dummy_thread_times;
+    NGCORE_API static std::array<size_t, NgProfiler::SIZE> dummy_thread_flops;
   private:
 
     NGCORE_API static std::string filename;
diff --git a/libsrc/core/utils.cpp b/libsrc/core/utils.cpp
index 0347d244..5f5376bd 100644
--- a/libsrc/core/utils.cpp
+++ b/libsrc/core/utils.cpp
@@ -33,7 +33,7 @@ namespace ngcore
       auto tick_end = GetTimeCounter();
       tend = WallTime();
 
-      return (tick_end-tick_start)/(tend-tstart);
+      return static_cast<double>(tick_end-tick_start)/(tend-tstart);
   }();
 
   const std::chrono::time_point<TClock> wall_time_start = TClock::now();