Author: [log in to unmask]
Date: Wed Mar 25 11:54:34 2015
New Revision: 2539

Log:
Add scalar utility methods for computing live time from standard scalar data.

Added:
    java/trunk/record-util/src/main/java/org/hps/record/scalars/ScalarUtilities.java

Added: java/trunk/record-util/src/main/java/org/hps/record/scalars/ScalarUtilities.java
 =============================================================================
--- java/trunk/record-util/src/main/java/org/hps/record/scalars/ScalarUtilities.java	(added)
+++ java/trunk/record-util/src/main/java/org/hps/record/scalars/ScalarUtilities.java	Wed Mar 25 11:54:34 2015
@@ -0,0 +1,90 @@
+package org.hps.record.scalars;
+
+/**
+ * Utilities methods for scalar data.
+ * <p>
+ * Currently this is used only for computing live time measurements from standard
+ * scalar data.
+ * 
+ * @author Jeremy McCormick <[log in to unmask]>
+ */
+public class ScalarUtilities {
+    
+    /**
+     * This class shouldn't be instantiated.
+     */
+    private ScalarUtilities() {        
+    }
+    
+    /**
+     * Indices for getting live time measurements.     
+     */
+    public enum LiveTimeIndex {
+        FCUP_TDC, /* Faraday cup TDC */
+        FCUP_TRG, /* Faraday cup TRG */
+        CLOCK; /* clock */
+    }
+    
+    /**
+     * Get the live time measurements from standard scalar data.
+     * <p>
+     * This is returned as a double array of size 3 containing:</br>
+     * <pre>
+     * [0] = FCUP TDC measurement
+     * [1] = FCUP TRG measurement
+     * [2] = CLOCK measurement
+     * </pre>
+     * This method assumes the standard scalar data structure as outlined in
+     * <a href="https://jira.slac.stanford.edu/browse/HPSJAVA-470">HPSJAVA-470</a>. 
+     * 
+     * @param data The scalar data.
+     * @return The live time measurements.
+     */
+    public static double[] getLiveTimes(ScalarData data) {
+        
+        // [03] - gated faraday cup with "TDC" threshold
+        int word03 = data.getValue(3);
+        
+        // [19] - gated faraday cup with "TRG" threshold
+        int word19 = data.getValue(19);
+
+        // [35] - ungated faraday cup with "TDC" threshold
+        int word35 = data.getValue(35);
+        
+        // [51] - ungated faraday cup with "TRG" threshold
+        int word51 = data.getValue(51);
+
+        // [67] - gated clock
+        int word67 = data.getValue(67);
+
+        // [68] - ungated clock
+        int word68 = data.getValue(68);
+        
+        // [03]/[35] = FCUP TDC
+        double fcupTdc = (double) word03 / (double) word35;
+        
+        // [19]/[51] = FCUP TRG
+        double fcupTrg = (double) word19 / (double) word51;
+        
+        // [67]/[68] = CLOCK
+        double clock = (double) word67 / (double) word68;
+        
+        // Compute the live times.
+        double[] liveTimes = new double[3];
+        liveTimes[0] = fcupTdc;
+        liveTimes[1] = fcupTrg;
+        liveTimes[2] = clock;
+        
+        return liveTimes;
+    }
+    
+    /**
+     * Get a specific live time measurement by index.
+     * @param index The enum of the index type.
+     * 
+     * @see LiveTimeIndex
+     */
+    public static double getLiveTime(ScalarData data, LiveTimeIndex index) {
+        return getLiveTimes(data)[index.ordinal()];
+    }
+}