diff --git a/src/tamaas.cpp b/src/tamaas.cpp
index 85f4145..c479258 100644
--- a/src/tamaas.cpp
+++ b/src/tamaas.cpp
@@ -1,46 +1,48 @@
 /**
  *
  * @author Lucas Frérot <lucas.frerot@epfl.ch>
  *
  * @section LICENSE
  *
  * Copyright (©)  2016 EPFL  (Ecole Polytechnique  Fédérale de
  * Lausanne)  Laboratory (LSMS  -  Laboratoire de  Simulation  en Mécanique  des
  * Solides)
  *
  * Tamaas is free  software: you can redistribute it and/or  modify it under the
  * terms  of the  GNU Lesser  General Public  License as  published by  the Free
  * Software Foundation, either version 3 of the License, or (at your option) any
  * later version.
  *
  * Tamaas is  distributed in the  hope that it  will be useful, but  WITHOUT ANY
  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  * A  PARTICULAR PURPOSE. See  the GNU  Lesser General  Public License  for more
  * details.
  *
  * You should  have received  a copy  of the GNU  Lesser General  Public License
  * along with Tamaas. If not, see <http://www.gnu.org/licenses/>.
  *
  */
 /* -------------------------------------------------------------------------- */
 
 #include <fftw3.h>
 #include <omp.h>
 #include "tamaas.hh"
 
 /* -------------------------------------------------------------------------- */
 
 __BEGIN_TAMAAS__
 
-void initialize() {
+void initialize(UInt num_threads) {
   fftw_init_threads();
+
+  if (num_threads) omp_set_num_threads(num_threads);
   fftw_plan_with_nthreads(omp_get_max_threads());
 }
 
 /* -------------------------------------------------------------------------- */
 
 void finalize() {
   fftw_cleanup_threads();
 }
 
 __END_TAMAAS__
diff --git a/src/tamaas.hh b/src/tamaas.hh
index 5adccf4..40ad29b 100644
--- a/src/tamaas.hh
+++ b/src/tamaas.hh
@@ -1,86 +1,89 @@
 /**
  *
  * @author Lucas Frérot <lucas.frerot@epfl.ch>
  * @author Guillaume Anciaux <guillaume.anciaux@epfl.ch>
  *
  * @section LICENSE
  *
  * Copyright (©)  2016 EPFL  (Ecole Polytechnique  Fédérale de
  * Lausanne)  Laboratory (LSMS  -  Laboratoire de  Simulation  en Mécanique  des
  * Solides)
  *
  * Tamaas is free  software: you can redistribute it and/or  modify it under the
  * terms  of the  GNU Lesser  General Public  License as  published by  the Free
  * Software Foundation, either version 3 of the License, or (at your option) any
  * later version.
  *
  * Tamaas is  distributed in the  hope that it  will be useful, but  WITHOUT ANY
  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  * A  PARTICULAR PURPOSE. See  the GNU  Lesser General  Public License  for more
  * details.
  *
  * You should  have received  a copy  of the GNU  Lesser General  Public License
  * along with Tamaas. If not, see <http://www.gnu.org/licenses/>.
  *
  */
 
 /* -------------------------------------------------------------------------- */
 
 #ifndef TAMAAS_HH
 #define TAMAAS_HH
 /* -------------------------------------------------------------------------- */
 #include <exception>
 #include <string>
 #include <complex>
 /* -------------------------------------------------------------------------- */
 
 /// Namespace macros
 #define __BEGIN_TAMAAS__ namespace tamaas {
 #define __END_TAMAAS__ }
 
 /* -------------------------------------------------------------------------- */
 __BEGIN_TAMAAS__
 /* -------------------------------------------------------------------------- */
-void initialize();
-void finalize();
-/* -------------------------------------------------------------------------- */
 
 /// Common types definitions
 typedef double Real;
 typedef unsigned int UInt;
 typedef int Int;
 typedef std::complex<Real> complex;
 static const Real zero_threshold = 1e-14;
 
 /* -------------------------------------------------------------------------- */
+/// initialize tamaas (0 threads => let OMP_NUM_THREADS decide)
+void initialize(UInt num_threads = 0);
+/// cleanup tamaas
+void finalize();
+/* -------------------------------------------------------------------------- */
+
 
 class SurfaceException : public std::exception {
 public:
   SurfaceException(const std::string & mesg) throw() {
     msg = mesg;
   }
 
   virtual const char* what() const throw() {
     return msg.c_str();
   }
 
 private:
   std::string msg;
 };
 /* -------------------------------------------------------------------------- */
 __END_TAMAAS__
 /* -------------------------------------------------------------------------- */
 
 #define SURFACE_FATAL(mesg)	{                   \
     std::stringstream sstr;                     \
     sstr                                        \
       <<  __FILE__                              \
       << ":" << __LINE__ << ":FATAL: "          \
       <<  mesg << std::endl;                    \
     std::cerr.flush();                          \
     throw ::tamaas::SurfaceException(sstr.str());	\
   }
 
 /* -------------------------------------------------------------------------- */
 
 #endif // TAMAAS_HH