fixed invalid isochrone calculation

added todo

src/main/java/it/unibz/inf/isochrone/algorithm/Isochrone.java

@@ -26,6 +26,7 @@ import java.util.Set;
  * algorithms which define the loading of the data from the database.
  */
 public abstract class Isochrone {
+	private static final double COMPARE_PRECISION = 0.0000001d;
 	private final Query query;
 	private final PriorityQueue<Node> queue;
 	private Set<Integer> codes;
@@ -116,6 +117,7 @@ public abstract class Isochrone {
 	 * @param output the output in which the computed nodes and links are stored.
 	 * @return the computed output (stored in the output given by the parameter)
 	 */
+	// TODO: Add some more tests for this method. If isochrone gets too small (2points for 15min isochrone from FUB) nothing fails ;-( 
 	public <T extends Output> T compute(final T output) {
 		output.beforeCalculation();
 
@@ -134,7 +136,7 @@ public abstract class Isochrone {
 			for (final Link link : adjacents) {
 				if (link.isContinuous()) {
 					updateQueue(expandContinuousLink(node, link));
-					if (Double.valueOf(Double.MIN_VALUE).equals(link.getStartOffset())) {
+					if (Math.abs(link.getStartOffset() - Double.MIN_VALUE) < COMPARE_PRECISION) {
 						output.addLink(link);
 					}
 				} else {

src/main/java/it/unibz/inf/isochrone/algorithm/MrneX.java

@@ -183,7 +183,7 @@ public class MrneX extends Isochrone {
 
 		// CHECKSTYLE:OFF MagicNumber
 		if (maxMemory * 0.95d < getNodeSize()) {
-			final double perc = 100.0d - (double) getNodeSize() / maxMemory * 100.0d;
+			final double perc = 100.0d - ((double) getNodeSize() / maxMemory) * 100.0d;
 			throw new RuntimeException("Free memory size is " + NumberFormat.getInstance().format(perc) + "%");
 		}
 		// CHECKSTYLE:ON MagicNumber