Fix warnings sign-compare.

dune/solvers/iterationsteps/semidefiniteblockgsstep.hh

@@ -48,8 +48,8 @@ class SemiDefiniteBlockGSStep
     std::size_t operator()(const typename MatrixType::block_type& A) const {
       std::hash<typename MatrixType::block_type::field_type> fieldHasher;
       std::size_t result = 123456789;
-      for(int i=0; i<A.N(); ++i)
-        for(int j=0; j<A.N(); ++j)
+      for(size_t i=0; i<A.N(); ++i)
+        for(size_t j=0; j<A.N(); ++j)
           result = (result * 123456789) ^ fieldHasher(A[i][j]);
       return result;
     }
@@ -139,7 +139,7 @@ public:
           it->mmv(x[col],r);
       }
       if (regularizeDiagonal_) {
-        for(int j=0; j<Aii.N(); ++j) {
+        for(size_t j=0; j<Aii.N(); ++j) {
           if (Aii[j][j]==0)
             Aii[j][j] = regularizeParameter_;
           else

dune/solvers/test/multigridtest.cc

@@ -58,7 +58,7 @@ struct MultigridTestSuite
 
         // we need a vector of pointers to the transfer operator base class
         std::vector<Transfer*> transfer(grid.maxLevel());
-        for (int i = 0; i < transfer.size(); ++i)
+        for (size_t i = 0; i < transfer.size(); ++i)
         {
             // create transfer operator from level i to i+1 (note that this will only work for either uniformly refined grids or adaptive grids with RefinementType=COPY)
             TransferImplementation* t = new TransferImplementation;

dune/solvers/test/projectedgradienttest.cc

@@ -29,7 +29,7 @@ bool solveObstacleProblemByProjectedGradientSolver(const GridType& grid, const M
 
     typedef std::vector<BoxConstraint<double, blockSize> > BoxConstraintVector;
     BoxConstraintVector boxConstraints(rhs.size());
-    for (int i = 0; i < boxConstraints.size(); ++i)
+    for (size_t i = 0; i < boxConstraints.size(); ++i)
     {
         for (int j = 0; j < blockSize; ++j)
         {