Fix issue with column ordering in the exemplars

If the max scale in the exemplar was a column we weren't using, it
would bail out when looking for that correlation later.  Change things
around so exemplars in RAM only keep around the columns we care about.

Makefile

@@ -11,10 +11,14 @@ endif
 test: test_trainola
 
 test_trainola:
+	-nilmtool -u http://bucket/nilmdb remove -s min -e max \
+		/sharon/prep-a-matches
+	nilmtools/trainola.py "$$(cat extras/trainola-test-param-2.js)"
 	-nilmtool -u http://bucket/nilmdb remove -s min -e max \
 		/sharon/prep-a-matches
 	nilmtools/trainola.py "$$(cat extras/trainola-test-param.js)"
 
+
 test_cleanup:
 	nilmtools/cleanup.py -e extras/cleanup.cfg
 	nilmtools/cleanup.py extras/cleanup.cfg

extras/trainola-test-param-2.js

@@ -0,0 +1,29 @@
+{ "columns" : [ { "index" : 0, "name" : "P1" },
+                { "index" : 1, "name" : "Q1" },
+                { "index" : 2, "name" : "P3" } ],
+  "stream" : "/sharon/prep-a",
+  "url" : "http://bucket.mit.edu/nilmdb",
+  "dest_stream" : "/sharon/prep-a-matches",
+  "start" : 1365153062643133.5,
+  "end"   : 1365168814443575.5,
+  "exemplars" : [ { "columns" : [ { "index" : 0,
+                                    "name" : "P1"
+                                  } ],
+                    "dest_column" : 0,
+                    "end" : 1365073657682000,
+                    "name" : "Turn ON",
+                    "start" : 1365073654321000,
+                    "stream" : "/sharon/prep-a",
+                    "url" : "http://bucket.mit.edu/nilmdb"
+                  },
+                  { "columns" : [ { "index" : 2, "name" : "P3" },
+                                  { "index" : 0, "name" : "P1" } ],
+                    "dest_column" : 1,
+                    "end" : 1365176528818000,
+                    "name" : "Type 2 turn ON",
+                    "start" : 1365176520030000,
+                    "stream" : "/sharon/prep-a",
+                    "url" : "http://bucket.mit.edu/nilmdb"
+                  }
+                ]
+}

nilmtools/trainola.py

@@ -28,12 +28,12 @@ def build_column_mapping(colinfo, streaminfo):
     pull out a dictionary mapping for the column names/numbers."""
     columns = OrderedDict()
     for c in colinfo:
-        if (c['name'] in columns.keys() or
-            c['index'] in columns.values()):
+        col_num = c['index'] + 1  # skip timestamp
+        if (c['name'] in columns.keys() or col_num in columns.values()):
             raise DataError("duplicated columns")
         if (c['index'] < 0 or c['index'] >= streaminfo.layout_count):
             raise DataError("bad column number")
-        columns[c['name']] = c['index']
+        columns[c['name']] = col_num
     if not len(columns):
         raise DataError("no columns")
     return columns
@@ -79,10 +79,17 @@ class Exemplar(object):
                                                    maxrows = self.count)
         self.data = list(datagen)[0]
 
-        # Discard timestamp
-        self.data = self.data[:,1:]
+        # Extract just the columns that were specified in self.columns,
+        # skipping the timestamp.
+        extract_columns = [ value for (key, value) in self.columns.items() ]
+        self.data = self.data[:,extract_columns]
 
-        # Subtract the mean from each column
+        # Fix the column indices in e.columns, since we removed/reordered
+        # columns in self.data
+        for n, k in enumerate(self.columns):
+            self.columns[k] = n
+
+        # Subtract the means from each column
         self.data = self.data - self.data.mean(axis=0)
 
         # Get scale factors for each column by computing dot product
@@ -147,7 +154,7 @@ def trainola_matcher(data, interval, args, insert_func, final_chunk):
 
         # Compute cross-correlation for each column
         for col_name in e.columns:
-            a = data[:, src_columns[col_name] + 1]
+            a = data[:, src_columns[col_name]]
             b = e.data[:, e.columns[col_name]]
             corr = scipy.signal.fftconvolve(a, np.flipud(b), 'valid')[0:valid]