Migration from SVN

eo/contrib/mathsym/gen/NodeSelector.cpp

@@ -0,0 +1,50 @@
+/*	    
+ *             Copyright (C) 2005 Maarten Keijzer
+ *
+ *          This program is free software; you can redistribute it and/or modify
+ *          it under the terms of version 2 of the GNU General Public License 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 General Public License for more details.
+ *
+ *          You should have received a copy of the GNU General Public License
+ *          along with this program; if not, write to the Free Software
+ *          Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "NodeSelector.h"
+#include "Sym.h"
+
+#include <utils/eoRNG.h>
+
+// If subtree is not set (by randomnodeselector for instance, find it now
+Sym NodeSelector::NodeSelection::subtree() {
+    if (subtree_.empty()) {
+	subtree_ = get_subtree(root_, subtree_index_);
+    }
+    return subtree_;
+}
+
+NodeSelector::NodeSelection RandomNodeSelector::select_node(Sym sym) const {
+    unsigned idx = rng.random(sym.size());
+    return  NodeSelection(sym, idx, Sym() ); // empty subtree, find it when needed
+}
+
+NodeSelector::NodeSelection BiasedNodeSelector::select_node(Sym sym) const {
+    
+    unsigned p = rng.random(sym.size());
+    Sym res;
+    for (unsigned i = 0; i < nRounds; ++i) {
+	res = get_subtree(sym, p);
+	
+	if (res.args().size() > 0) break;
+	
+	p = rng.random(sym.size());
+    }
+    
+    return NodeSelection(sym, p, res);
+}
+