diff --git a/src/examples/solver/test_ccolamd.cpp b/src/examples/solver/test_ccolamd.cpp
index 1301856eb14a3d202066a0774f508cb5468f40e3..6f2bc47ecf2bb1dc1ababc7030f2455b7fd62fd8 100644
--- a/src/examples/solver/test_ccolamd.cpp
+++ b/src/examples/solver/test_ccolamd.cpp
@@ -50,7 +50,7 @@ int main(int argc, char *argv[])
     //Fill A & b
     A.insert(0, 0) = 5;
     b(0) = 1;
-    for (unsigned int i = 1; i < size; i++)
+    for (int i = 1; i < size; i++)
     {
         A.insert(i, i) = 5;
         A.insert(i, i - 1) = 1;
diff --git a/src/examples/solver/test_ccolamd_blocks.cpp b/src/examples/solver/test_ccolamd_blocks.cpp
index 64421f502818c7a0f5095160968487698d9a483e..8c5c91219a1c11f3e35472a4c46b335db689921f 100644
--- a/src/examples/solver/test_ccolamd_blocks.cpp
+++ b/src/examples/solver/test_ccolamd_blocks.cpp
@@ -46,7 +46,7 @@ void permutation_2_block_permutation(const PermutationMatrix<Dynamic, Dynamic, i
 {
     ArrayXXi idx(dim, size);
     idx.row(0) = dim * perm.indices().transpose();
-    for (unsigned int i = 1; i<dim; i++)
+    for (int i = 1; i<dim; i++)
         idx.row(i) = idx.row(i-1) + 1;
     Map<ArrayXi> idx_blocks(idx.data(), dim*size, 1);
     perm_blocks.indices() = idx_blocks;
@@ -82,7 +82,7 @@ int main(int argc, char *argv[])
 
     // BUILD THE PROBLEM ----------------------------
     //Fill H & b
-    for (unsigned int i = 0; i < size; i++)
+    for (int i = 0; i < size; i++)
     {
         addSparseBlock(5*omega, H, i*dim, i*dim);
         FactorMatrix.insert(i,i) = 1;
diff --git a/src/examples/solver/test_iQR.cpp b/src/examples/solver/test_iQR.cpp
index da96af297bc3f8592f125ce160f493a922568f94..79bfb03b31d1de81602113003d1e5028f15a328a 100644
--- a/src/examples/solver/test_iQR.cpp
+++ b/src/examples/solver/test_iQR.cpp
@@ -80,7 +80,7 @@ void permutation_2_block_permutation(const PermutationMatrix<Dynamic, Dynamic, i
     ArrayXXi idx(dim, perm_nodes.indices().rows());
     idx.row(0) = dim * perm_nodes.indices().transpose();
 
-    for (unsigned int i = 1; i<dim; i++)
+    for (int i = 1; i<dim; i++)
         idx.row(i) = idx.row(i-1) + 1;
     Map<ArrayXi> idx_blocks(idx.data(), dim*perm_nodes.indices().rows(), 1);
     perm_variables.indices() = idx_blocks;
@@ -141,7 +141,7 @@ int main(int argc, char *argv[])
 
     // GENERATING MEASUREMENTS
     std::vector<std::vector<int>> measurements;
-    for (unsigned int i = 0; i < size; i++)
+    for (int i = 0; i < size; i++)
     {
         std::vector<int> meas(0);
         if (i == 0) //prior
diff --git a/src/examples/solver/test_iQR_wolf.cpp b/src/examples/solver/test_iQR_wolf.cpp
index 61892690dab0cdf54b634e8f3e1bebfd2e8f72ff..59b90abf761007a918a605f00acc8f67a8a967ca 100644
--- a/src/examples/solver/test_iQR_wolf.cpp
+++ b/src/examples/solver/test_iQR_wolf.cpp
@@ -157,6 +157,10 @@ class SolverQR
             acc_node_permutation_(0),
 //            nodes_(0),
 //            measurements_(0),
+            first_ordered_node_(0),
+            t_ordering_(0),
+            t_solving_(0),
+            t_managing_(0),
             time_ordering_(0),
             time_solving_(0),
             time_managing_(0)
@@ -446,7 +450,7 @@ class SolverQR
 
             // update nodes orders and locations
             ArrayXi locations = perm_nodes_2_locations(acc_node_permutation_);
-            for (int i = 0; i < nodes_.size(); i++)
+            for (unsigned int i = 0; i < nodes_.size(); i++)
             {
                 nodes_.at(i).order = acc_node_permutation_.indices()(i);
                 nodes_.at(i).location = locations(i);
@@ -503,7 +507,7 @@ int main(int argc, char *argv[])
 
     // GENERATING MEASUREMENTS
     std::vector<measurement> measurements;
-    for (unsigned int i = 0; i < size; i++)
+    for (int i = 0; i < size; i++)
     {
         std::vector<int> meas(0);
         if (i == 0) //prior
diff --git a/src/examples/solver/test_incremental_ccolamd_blocks.cpp b/src/examples/solver/test_incremental_ccolamd_blocks.cpp
index ca39a9d2e18687f91bf11a65dd90f7dbb8f10cfb..de4f82f00b083cb6edf88180ece6fb238cec09b6 100644
--- a/src/examples/solver/test_incremental_ccolamd_blocks.cpp
+++ b/src/examples/solver/test_incremental_ccolamd_blocks.cpp
@@ -48,7 +48,7 @@ void permutation_2_block_permutation(const PermutationMatrix<Dynamic, Dynamic, i
     ArrayXXi idx(dim, size);
     idx.row(0) = dim * perm.indices().transpose();
 
-    for (unsigned int i = 1; i<dim; i++)
+    for (int i = 1; i<dim; i++)
         idx.row(i) = idx.row(i-1) + 1;
     Map<ArrayXi> idx_blocks(idx.data(), dim*size, 1);
     perm_blocks.indices() = idx_blocks;
@@ -108,7 +108,7 @@ int main(int argc, char *argv[])
     std::cout << "STARTING INCREMENTAL TEST" << std::endl << std::endl;
 
     // INCREMENTAL LOOP
-    for (unsigned int i = 1; i < size; i++)
+    for (int i = 1; i < size; i++)
     {
         std::cout << "========================= STEP " << i << ":" << std::endl;
         // AUGMENT THE PROBLEM ----------------------------