# HG changeset patch
# User Sascha L. Teichmann <sascha.teichmann@intevation.de>
# Date 1304343722 0
# Node ID 20c3a5b36434c6cec2bcffc87c332f7bea2401b6
# Parent  0ccf7200fc518c4e9ca70b9a9b0b95c4fe5c4633
Repaired DischargeTables.getQForW()

flys-artifacts/trunk@1790 c6561f87-3c4e-4783-a992-168aeb5c3f6f

diff -r 0ccf7200fc51 -r 20c3a5b36434 flys-artifacts/ChangeLog
--- a/flys-artifacts/ChangeLog	Mon May 02 12:47:10 2011 +0000
+++ b/flys-artifacts/ChangeLog	Mon May 02 13:42:02 2011 +0000
@@ -1,3 +1,8 @@
+2011-05-02	Sascha L. Teichmann	<sascha.teichmann@intevation.de>
+
+	* src/main/java/de/intevation/flys/artifacts/model/DischargeTables.java:
+	  Repaired getQForW() by calculating indices on right dimension.
+
 2011-05-02  Ingo Weinzierl <ingo@intevation.de>
 
 	* src/main/java/de/intevation/flys/artifacts/FLYSArtifact.java: New
diff -r 0ccf7200fc51 -r 20c3a5b36434 flys-artifacts/src/main/java/de/intevation/flys/artifacts/model/DischargeTables.java
--- a/flys-artifacts/src/main/java/de/intevation/flys/artifacts/model/DischargeTables.java	Mon May 02 12:47:10 2011 +0000
+++ b/flys-artifacts/src/main/java/de/intevation/flys/artifacts/model/DischargeTables.java	Mon May 02 13:42:02 2011 +0000
@@ -180,6 +180,13 @@
     }
 
     public static double getQForW(double [][] values, double w) {
+
+        boolean debug = log.isDebugEnabled();
+
+        if (debug) {
+            log.debug("calculating getQForW(" + w + ")");
+        }
+
         int index = Arrays.binarySearch(values[0], w);
         if (index >= 0) {
             return values[0][index];
@@ -187,15 +194,18 @@
 
         index = -index - 1; // insert position
 
-        if (index < 1 || index >= values.length) {
+        if (index < 1 || index >= values[0].length) {
             // do not extraploate
+            if (debug) {
+                log.debug("we do not extrapolate: NaN");
+            }
             return Double.NaN;
         }
 
-        double w1 = values[index-1][0];
-        double w2 = values[index  ][0];
-        double q1 = values[index-1][1];
-        double q2 = values[index  ][1];
+        double w1 = values[0][index-1];
+        double w2 = values[0][index  ];
+        double q1 = values[1][index-1];
+        double q2 = values[1][index  ];
 
         // q1 = m*w1 + b
         // q2 = m*w2 + b
@@ -203,13 +213,22 @@
         // m = (q2 - q1)/(w2 - w1) # w2 != w1
         // b = q1 - m*w1
 
+        double q;
         if (w1 == w2) {
-            return 0.5*(q1 + q2);
+            q = 0.5*(q1 + q2);
+            if (debug) {
+                log.debug("same w1 and w1: " + w1);
+            }
         }
-
-        double m = (q2 - q1)/(w2 - w1);
-        double b = q1 - m*w1;
-        return w*m + b;
+        else {
+            double m = (q2 - q1)/(w2 - w1);
+            double b = q1 - m*w1;
+            q = w*m + b;
+        }
+        if (debug) {
+            log.debug("Q(" + w + ") = " + q);
+        }
+        return q;
     }
 }
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