1 files changed, 33 insertions, 0 deletions

diff --git a/src/uk/ac/ox/cs/pagoda/util/ExponentialInterpolation.java b/src/uk/ac/ox/cs/pagoda/util/ExponentialInterpolation.java
new file mode 100644
index 0000000..1d12169
--- /dev/null
+++ b/src/uk/ac/ox/cs/pagoda/util/ExponentialInterpolation.java
@@ -0,0 +1,33 @@
+package uk.ac.ox.cs.pagoda.util;
+
+/***
+ * Get an exponential function given two points.
+ */
+public class ExponentialInterpolation {
+
+    private final double base;
+    private final double multiplicativeFactor;
+
+    /***
+     * Compute the exponential function passing for the 2 given points.
+     *
+     * @param x1
+     * @param y1
+     * @param x2
+     * @param y2
+     */
+    public ExponentialInterpolation(double x1, double y1, double x2, double y2) {
+        base = Math.pow(y2/y1, 1 / (x2 - x1));
+        multiplicativeFactor = y1 / Math.pow(base, x1);
+    }
+
+    /***
+     * Compute value of the function in x.
+     *
+     * @param x
+     * @return
+     */
+    public double computeValue(double x) {
+        return multiplicativeFactor * Math.pow(base, x);
+    }
+}