--- /dev/null
+/*
+ * Copyright (c) 2003-2005 The BISON Project
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+package peersim.vector;
+
+import peersim.config.*;
+import peersim.core.*;
+
+/**
+ * Normalizes the values of a protocol vector.
+ * The normalization is based on the L1 norm, that is, the sum of the
+ * absolute values of the vector elements. Parameter {@value #PAR_L1} defines
+ * the L1 norm that the vector will have after normalization.
+ * @see VectControl
+ * @see peersim.vector
+ */
+public class Normalizer extends VectControl
+{
+
+// --------------------------------------------------------------------------
+// Parameters
+// --------------------------------------------------------------------------
+
+/**
+ * The L1 norm (sum of absolute values) to normalize to. After the operation the
+ * L1 norm will be the value given here. Defaults to 1.
+ * @config
+ */
+private static final String PAR_L1 = "l1";
+
+
+// --------------------------------------------------------------------------
+// Fields
+// --------------------------------------------------------------------------
+
+/** L1 norm */
+private final double l1;
+
+
+// --------------------------------------------------------------------------
+// Initialization
+// --------------------------------------------------------------------------
+
+/**
+ * Standard constructor that reads the configuration parameters.
+ * Invoked by the simulation engine.
+ * @param prefix the configuration prefix for this class
+ */
+public Normalizer(String prefix)
+{
+ super(prefix);
+ l1 = Configuration.getDouble(prefix + "." + PAR_L1, 1);
+
+ if( setter.isInteger() )
+ throw new IllegalParameterException(prefix + "." + PAR_METHOD,
+ "setter value must be floating point, instead of "+
+ setter.getType());
+
+ if( setter.getType() != getter.getType() )
+ throw new IllegalParameterException(prefix + "." + PAR_GETTER,
+ "getter and setter must have the same numeric type, "+
+ "but we have "+setter.getType()+" and "+getter.getType());
+}
+
+//--------------------------------------------------------------------------
+//Methods
+//--------------------------------------------------------------------------
+
+/**
+ * Makes the sum of the absolute values (L1 norm) equal to the value
+ * given in the configuration parameter {@value #PAR_L1}. If the value is
+ * negative, the L1 norm will be the absolute value and the vector elements
+ * change sign.
+ * @return always false
+ */
+public boolean execute() {
+
+ double sum = 0.0;
+ for (int i = 0; i < Network.size(); ++i)
+ {
+ sum += getter.getDouble(i);
+ }
+ if (sum == 0.0)
+ {
+ throw new
+ RuntimeException("Attempted to normalize all zero vector.");
+ }
+ double factor = l1 / sum;
+ for (int i = 0; i < Network.size(); ++i)
+ {
+ double val = getter.getDouble(i)*factor;
+ setter.set(i,val);
+ }
+ return false;
+}
+
+//--------------------------------------------------------------------------
+
+}
