gcim start

src/org/opensha2/gcim/ImCorrelation.java

@@ -0,0 +1,97 @@
+package org.opensha2.gcim;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static java.lang.Math.*;
+import org.opensha2.gmm.Imt;
+
+/**
+ * Add comments here
+ *
+ * @author Peter Powers
+ */
+public enum ImCorrelation {
+
+	BAKER_07("Baker (2007)") {
+		@Override double get(Imt im1, Imt im2) {
+			return 0;
+			// TODO do nothing
+
+		}
+	},
+
+	BAKER_JARAYAM_08("") {
+		@Override double get(Imt im1, Imt im2) {
+			return computeBakerJaraym08(im1, im2);
+		}
+	},
+
+	BRADLEY_11("") {
+		@Override double get(Imt im1, Imt im2) {
+			return 0;
+			// TODO do nothing
+
+		}
+	},
+
+	GODA_ATKINSON_09("") {
+		@Override double get(Imt im1, Imt im2) {
+			return 0;
+			// TODO do nothing
+
+		}
+	};
+
+	private String label;
+	private ImCorrelation(String label) {
+		this.label = label;
+	}
+
+	/**
+	 * Compute the correlation between two intensity measures.
+	 */
+	abstract double get(Imt im1, Imt im2);
+
+	private static double computeBakerJaraym08(Imt imi, Imt imj) {
+		checkArgument(imi.isSA() && imj.isSA(), "Supplied IMTs are not SA intensity measures");
+
+		double ti = imi.period();
+		double tj = imj.period();
+
+		double t_min = min(ti, tj);
+		double t_max = max(ti, tj);
+		double c2 = Double.NaN;
+		double c3;
+		double c4;
+
+		double c1 = (1.0 - cos(PI / 2.0 - log(t_max / max(t_min, 0.109)) * 0.366));
+
+		if (t_max < 0.2) {
+			c2 = 1.0 - 0.105 *
+				(1.0 - 1.0 / (1.0 + exp(100.0 * t_max - 5.))) *
+				(t_max - t_min) / (t_max - 0.0099);
+		}
+
+//		if (t_max < 0.109) {
+//			c3 = c2;
+//		} else {
+//			c3 = c1;
+//		}
+		c3 = (t_max < 0.109) ? c2 : c1;
+
+		c4 = c1 + 0.5 * (sqrt(c3) - c3) * (1. + cos(PI * t_min / 0.109));
+
+		if (t_max <= 0.109) {
+			return c2;
+		} else if (t_min > 0.109) {
+			return c1;
+		} else if (t_max < 0.2) {
+			return min(c2, c4);
+		} else {
+			return c4;
+		}
+
+		// return (t_max <= 0.109) ? c2 : (t_min > 0.109) ? c1 : (t_max < 0.2) ?
+		// min(c2, c4) : c4;
+
+	}
+}