Constant mutation + simplification added

eo/contrib/mathsym/fun/FunDef.cpp

@@ -287,7 +287,7 @@ Sym set_constants(Sym sym, vector<double>::const_iterator& it) {
 
     SymVec args = sym.args();
     for (unsigned i = 0; i < args.size(); ++i) {
-	 args[i] = set_constants(sym, it);
+	 args[i] = set_constants(args[i], it);
     }
     
     return Sym(token, args);

eo/contrib/mathsym/fun/FunDef.h

@@ -85,6 +85,12 @@ extern bool is_constant(token_t token);
 /** Create variable */
 extern Sym SymVar(unsigned idx);
 
+/** simplifies a sym (sym_operations.cpp) */
+extern Sym simplify(Sym sym);
+
+/** differentiates a sym to a token (sym_operations.cpp) */
+extern Sym differentiate(Sym sym, token_t var_token);
+
 /* Add function to the language table (and take a guess at the arity) */
 class LanguageTable;
 extern void add_function_to_table(LanguageTable& table, token_t token);

eo/contrib/mathsym/fun/sym_operations.cpp

@@ -0,0 +1,76 @@
+/*	    
+ *             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 <FunDef.h>
+
+using namespace std;
+
+Sym simplify_constants(Sym sym) {
+
+    SymVec args = sym.args();
+    token_t token = sym.token();
+    
+    bool has_changed = false;
+    bool all_constants = true;
+
+    for (unsigned i = 0; i < args.size(); ++i) {
+	
+	Sym arg = simplify_constants(args[i]);
+	
+	if (arg != args[i]) {
+	    has_changed = true;
+	}
+	args[i] = arg;
+
+	
+	all_constants &= is_constant(args[i].token());
+    }
+    
+    if (args.size() == 0) return sym; // variable or constant
+   
+    
+    if (all_constants) {
+	// evaluate 
+	
+	vector<double> dummy;
+	
+	vector<double> vals(args.size());
+	for (unsigned i = 0; i < vals.size(); ++i) {
+	    vals[i] = eval(sym, dummy);
+	}
+	
+	Sym result = SymConst( get_element(token).eval(vals, dummy) );
+	
+	
+	return result;
+    }
+
+    if (has_changed) {
+	return Sym(token, args);
+    }
+
+    return sym;
+    
+}
+
+// currently only simplifies constants
+Sym simplify(Sym sym) {
+    
+    return simplify_constants(sym);
+    
+}
+