 	import weave.core.LinkableString;
 	import weave.core.UntypedLinkableVariable;
 	import weave.utils.ColumnUtils;
+	import weave.utils.Dictionary2D;
 	import weave.utils.EquationColumnLib;
 	
 	/**

		/**
		 * This is a mapping from keys to cached data values.
		 */
		private var _equationResultCache:Dictionary = new Dictionary();
		/**
		 * This is used to determine when to clear the cache.
		 */		

					}
					
					// save value in cache
					_equationResultCache.set(key, dataType, value);
					//trace('('+equation.value+')@"'+key+'" = '+value);
				}
				else if (value === UNDEFINED)
