fix some warnings

MathLib/LinAlg/Eigen/EigenMatrix.h

@@ -156,6 +156,7 @@ public:
     /// printout this matrix for debugging
     void write(std::ostream &os) const
     {
+        (void)os;
 #if 0
         for (int k=0; k<_mat.outerSize(); ++k)
           for (Eigen::SparseMatrix<double>::InnerIterator it(_mat,k); it; ++it)

NumLib/DOF/LocalToGlobalIndexMap.cpp

@@ -56,12 +56,12 @@ LocalToGlobalIndexMap::LocalToGlobalIndexMap(
 
     _variable_component_offsets.reserve(_mesh_subsets.size());
     std::size_t offset = 0;
-    for (int variable_id = 0; variable_id < _mesh_subsets.size();
+    for (int variable_id = 0; variable_id < static_cast<int>(_mesh_subsets.size());
          ++variable_id)
     {
         _variable_component_offsets.push_back(offset);
         auto const& mss = *_mesh_subsets[variable_id];
-        for (int component_id = 0; component_id < mss.size();
+        for (int component_id = 0; component_id < static_cast<int>(mss.size());
              ++component_id)
         {
             MeshLib::MeshSubset const& ms = mss.getMeshSubset(component_id);

ProcessLib/NeumannBc.cpp

@@ -28,7 +28,7 @@ NeumannBc::NeumannBc(
     : _function(*bc.getFunction()),
       _integration_order(integration_order)
 {
-    assert(component_id < local_to_global_index_map.getNumberOfComponents());
+    assert(component_id < static_cast<int>(local_to_global_index_map.getNumberOfComponents()));
 
     // deep copy because the neumann bc config destroys the elements.
     std::transform(bc.elementsBegin(), bc.elementsEnd(),