Add white gaussian noise function.

	* mln/fun/all.hh: Include a new file.

	* mln/fun/n2v/all.hh,
	* mln/fun/n2v/white_gaussian.hh: New.

milena/ChangeLog

+2010-02-24  Guillaume Lazzara  <z@lrde.epita.fr>
+
+	Add white gaussian noise function.
+
+	* mln/fun/all.hh: Include a new file.
+
+	* mln/fun/n2v/all.hh,
+	* mln/fun/n2v/white_gaussian.hh: New.
+
 2010-02-16  Guillaume Lazzara  <z@lrde.epita.fr>
 	Cleanup to_qimage convertion routines.

milena/mln/fun/all.hh

@@ -57,6 +57,8 @@ namespace mln
 
 // Sub-directories.
 
+# include <mln/fun/n2v/all.hh>
+
 # include <mln/fun/i2v/all.hh>
 //<<lrde
 # include <mln/fun/meta/all.hh>

milena/mln/fun/n2v/all.hh

+// Copyright (C) 2010 EPITA Research and Development Laboratory (LRDE)
+//
+// This file is part of Olena.
+//
+// Olena is free software: you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation, version 2 of the License.
+//
+// Olena 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
+// General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Olena.  If not, see <http://www.gnu.org/licenses/>.
+//
+// As a special exception, you may use this file as part of a free
+// software project without restriction.  Specifically, if other files
+// instantiate templates or use macros or inline functions from this
+// file, or you compile this file and link it with other files to produce
+// an executable, this file does not by itself cause the resulting
+// executable to be covered by the GNU General Public License.  This
+// exception does not however invalidate any other reasons why the
+// executable file might be covered by the GNU General Public License.
+
+#ifndef MLN_FUN_N2V_ALL_HH
+# define MLN_FUN_N2V_ALL_HH
+
+/// \file
+///
+/// File that includes all functions from nil to value.
+
+
+namespace mln
+{
+
+  namespace fun
+  {
+
+    /// \brief Namespace of functions from nil to value.
+    ///
+    /// \ingroup modfun
+    namespace n2v {}
+
+  }
+}
+
+
+# include <mln/fun/n2v/white_gaussian.hh>
+
+#endif // ! MLN_FUN_N2V_ALL_HH

milena/mln/fun/n2v/white_gaussian.hh

+// Copyright (C) 2010 EPITA Research and Development Laboratory (LRDE)
+//
+// This file is part of Olena.
+//
+// Olena is free software: you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation, version 2 of the License.
+//
+// Olena 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
+// General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Olena.  If not, see <http://www.gnu.org/licenses/>.
+//
+// As a special exception, you may use this file as part of a free
+// software project without restriction.  Specifically, if other files
+// instantiate templates or use macros or inline functions from this
+// file, or you compile this file and link it with other files to produce
+// an executable, this file does not by itself cause the resulting
+// executable to be covered by the GNU General Public License.  This
+// exception does not however invalidate any other reasons why the
+// executable file might be covered by the GNU General Public License.
+
+#ifndef MLN_FUN_N2V_WHITE_GAUSSIAN_HH
+# define MLN_FUN_N2V_WHITE_GAUSSIAN_HH
+
+/// \file
+///
+/// White Gaussian noise.
+
+# include <cstdlib>
+# include <ctime>
+
+# include <mln/core/concept/function.hh>
+
+
+
+namespace mln
+{
+
+  namespace fun
+  {
+
+    namespace n2v
+    {
+
+      /*! \brief Generate a White Gaussian Noise.
+
+
+	Reference:
+	http://www.dspguru.com/dsp/howtos/how-to-generate-white-gaussian-noise
+       */
+      template <typename V>
+      struct white_gaussian : Function_n2v< white_gaussian<V> >
+      {
+	typedef V result;
+
+	white_gaussian(double sigma_);
+	V operator()() const;
+
+	double sigma;
+      };
+
+
+# ifndef MLN_INCLUDE_ONLY
+
+
+      template <typename V>
+      white_gaussian<V>::white_gaussian(double sigma_)
+	: sigma(sigma_)
+      {
+	srand(time(0));
+      }
+
+
+      template <typename V>
+      V white_gaussian<V>::operator()() const
+      {
+	double X = 0;
+	for (int i = 1; i < 50; ++i)
+	{
+	  double U = rand() / (float)RAND_MAX;
+	  X = X + U;
+	}
+
+	X = X - 25.f;                /* set mean to 0 */
+	X = X * sqrt(12 / 50.f);     /* adjust variance to 1 */
+
+	return sigma * X;
+      };
+
+
+# endif // ! MLN_INCLUDE_ONLY
+
+    } // end of namespace mln::fun::n2v
+
+  } // end of namespace mln::fun
+
+} // end of namespace mln
+
+
+#endif // ! MLN_FUN_N2V_WHITE_GAUSSIAN_HH