Minor problem updates

src/eva2/server/go/problems/F20Problem.java

@@ -99,7 +99,7 @@ public class F20Problem extends AbstractProblemDouble implements Serializable, I
 
 	public SolutionHistogram getHistogram() {
 		if (getProblemDimension()==10) {
-			if (getYOffset()==0) return new SolutionHistogram(-5000, -3400, 16);
+			if (getYOffset()==0) return new SolutionHistogram(-5200, -3600, 16);
 			else return new SolutionHistogram(0, 1600, 16);
 		}
 		if (getProblemDimension()==30) {

src/eva2/server/go/problems/F21Problem.java

@@ -0,0 +1,106 @@
+package eva2.server.go.problems;
+
+import java.util.Random;
+
+import eva2.gui.BeanInspector;
+import eva2.server.go.operators.postprocess.SolutionHistogram;
+
+/**
+ * Langerman function: A non-separable function built from random peaks each of which is surrounded by circular ridges.
+ * The number of optima is equal to the number of dimensions.
+ * The positions and height values of the peaks are initialized randomly with a fixed seed for reproducibility.
+ * 
+ * @author mkron
+ *
+ */
+public class F21Problem extends AbstractProblemDouble implements InterfaceMultimodalProblem, InterfaceInterestingHistogram{
+	private double[] heights = null; // will receive random positions within the range
+	private double[][] peaks = null; // will receive values in [0,1] as peak height values
+	private static final int rndSeed=23;
+	private int dim=2;
+	
+	public F21Problem() {
+	}
+	
+	public F21Problem(F21Problem f21Problem) {
+		this();
+	}
+
+	public String getName() {
+		return "Langerman-Function";
+	}
+	
+	public static String globalInfo() {
+		return "The Langerman function, with n peaks each of which surrounded by circular ridges.";
+	}
+	
+	@Override
+	public double getRangeLowerBound(int dim) {
+		return 0;
+	}
+
+	@Override
+	public double getRangeUpperBound(int dim) {
+		return 10;
+	}
+
+	@Override
+	public void initProblem() {
+		super.initProblem();
+		Random rnd = new Random(rndSeed);
+		heights=new double[getProblemDimension()];
+		peaks=new double[getProblemDimension()][];
+		for (int i=0; i<getProblemDimension(); i++) {
+			heights[i]=rnd.nextDouble();
+			peaks[i]=new double[getProblemDimension()];
+			for (int j=0; j<getProblemDimension(); j++) {
+				peaks[i][j]=getRangeLowerBound(i)+rnd.nextDouble()*(getRangeUpperBound(i)-getRangeLowerBound(i));
+			}
+		}
+//		System.out.println("peaks is " + BeanInspector.toString(peaks));
+//		System.out.println("heights is " + BeanInspector.toString(heights));
+	}
+
+	@Override
+	public double[] eval(double[] x) {
+		double res[] = new double[1];
+		double tmp, innerSum, sum=0;
+		x = rotateMaybe(x);
+		
+		for (int i=0; i<x.length; i++) {
+			innerSum=0;
+			for (int j=0; j<x.length; j++) { 
+				tmp=(x[j]-peaks[i][j]); 
+				innerSum+=(tmp*tmp);
+			}
+			sum+=(heights[i]*
+					Math.exp(-(1./Math.PI)*innerSum)*
+					Math.cos(Math.PI*innerSum));
+		}
+		
+		res[0] = 1-sum;
+		return res;
+	}
+
+	@Override
+	public int getProblemDimension() {
+		return dim;
+	}
+	public void setProblemDimension(int d) {
+		dim=d;
+	}
+	public String problemDimensionTipText() {
+		return "The problem dimension and number of optima.";
+	}
+	
+	@Override
+	public Object clone() {
+		return new F21Problem(this);
+	}
+
+	@Override
+	public SolutionHistogram getHistogram() {
+		return new SolutionHistogram(0, 0.5, 10);
+	}
+
+}