diff --git a/SConstruct b/SConstruct
index a8beec38fc6ff57f91b75ab62fb27bdcbaeea7b3..dee6ab2a06a0d21044143a92a28cafea18319dc1 100644
--- a/SConstruct
+++ b/SConstruct
@@ -6,7 +6,7 @@ debug = ARGUMENTS.get('debug', 0)
 env = Environment(  #variables = vars,
                     CXX = 'g++',
                     CXXFLAGS = Split('-I./include -I./src \
-                    -march=native -mtune=native -std=gnu++11 -fabi-version=6 \
+                    -march=native -mtune=native -std=gnu++14 -fabi-version=6 \
                    -fpermissive -Wall -Wextra -fopenmp'),
                    LIBPATH = '#lib/',
                    LIBS = Split('-lopenblas -lgivaro -lgmpxx -lgmp'),
diff --git a/src/linalg/matrix_factory.h b/src/linalg/matrix_factory.h
index 35c7b83f85a2feab79551f8c30f119b91b2b5612..6dfd6c3292d8dd7ae412523546736324127b83bb 100644
--- a/src/linalg/matrix_factory.h
+++ b/src/linalg/matrix_factory.h
@@ -18,23 +18,23 @@ class MatrixFactory {
   public:
   // TODO(pj): Check that no zero element is added
   // TODO(pj): Is the vector of monomials required?
-  static std::shared_ptr<SpMat> BuildSparseUpperTriangular(
+  static std::unique_ptr<SpMat> BuildSparseUpperTriangular(
      const std::vector<std::pair<Monomial, PolynomialInMatrix> >&,
      const std::vector<Monomial>&);
 
-  static std::shared_ptr<RowMajMat> BuildRowMajor(
+  static std::unique_ptr<RowMajMat> BuildRowMajor(
      const std::vector<std::pair<Monomial, PolynomialInMatrix> >&,
      const std::vector<Monomial>&); 
 
-  static std::shared_ptr<RowMajMat> BuildRowMajor(
+  static std::unique_ptr<RowMajMat> BuildRowMajor(
       const std::vector<Polynomial>&,
       const std::vector<Monomial>&);
 };
 
-std::shared_ptr<SpMat> MatrixFactory::BuildSparseUpperTriangular(
+std::unique_ptr<SpMat> MatrixFactory::BuildSparseUpperTriangular(
      const std::vector<std::pair<Monomial, PolynomialInMatrix> >& list_reductors,
      const std::vector<Monomial>& list_monomials) {
-  auto R = std::make_shared<SpMat>();
+  auto R = std::make_unique<SpMat>();
   R->nb_nonzero_elts_by_row_.clear();
   R->row_size_ = list_reductors.size();
   R->column_size_ = list_monomials.size();
@@ -62,10 +62,10 @@ std::shared_ptr<SpMat> MatrixFactory::BuildSparseUpperTriangular(
   return R;
 }
 
-std::shared_ptr<RowMajMat> MatrixFactory::BuildRowMajor(
+std::unique_ptr<RowMajMat> MatrixFactory::BuildRowMajor(
     const std::vector<std::pair<Monomial, PolynomialInMatrix> > &list_reductors,
     const std::vector<Monomial> &list_monomials) {
-  auto R = std::make_shared<RowMajMat>(list_reductors.size(), list_monomials.size());
+  auto R = std::make_unique<RowMajMat>(list_reductors.size(), list_monomials.size());
   Polynomial tmp;
   std::map<Monomial, std::size_t> map_mon;
   for (std::size_t i = 0; i < list_monomials.size(); ++i)
@@ -84,10 +84,10 @@ std::shared_ptr<RowMajMat> MatrixFactory::BuildRowMajor(
 
 // TODO: if the input polynomials must be monic, then this should be specified
 // in an assert
-std::shared_ptr<RowMajMat> MatrixFactory::BuildRowMajor(
+std::unique_ptr<RowMajMat> MatrixFactory::BuildRowMajor(
     const std::vector<Polynomial>& list_pols,
     const std::vector<Monomial>& list_monomials) {
-  auto R = std::make_shared<RowMajMat>(list_pols.size(), list_monomials.size());
+  auto R = std::make_unique<RowMajMat>(list_pols.size(), list_monomials.size());
   std::map<Monomial, std::size_t> map_mon;
   for (std::size_t i = 0; i < list_monomials.size(); ++i)
     map_mon.insert(std::pair<Monomial, std::size_t>(list_monomials[i], i));