Add nilm-decimate-auto script

setup.py

@@ -72,6 +72,7 @@ setup(name='nilmtools',
       entry_points = {
           'console_scripts': [
               'nilm-decimate = nilmtools.decimate:main',
+              'nilm-decimate-auto = nilmtools.decimate_auto:main',
               'nilm-insert = nilmtools.insert:main',
               'nilm-copy = nilmtools.copy_:main',
               'nilm-sinefit = nilmtools.sinefit:main',

src/decimate_auto.py

@@ -0,0 +1,78 @@
+#!/usr/bin/python
+
+import nilmtools.filter
+import nilmtools.decimate
+import nilmdb.client
+import argparse
+
+def get_stream_info(client, path):
+    """Return a nilmtools.filter.StreamInfo object about the given
+    path, or None if it doesn't exist"""
+    streams = client.stream_list(path, extended = True)
+    if len(streams) != 1:
+        return None
+    return nilmtools.filter.StreamInfo(client.geturl(), streams[0])
+
+def main(argv = None):
+    parser = argparse.ArgumentParser(
+        formatter_class = argparse.RawDescriptionHelpFormatter,
+        version = "1.0",
+        description = """\
+    Automatically create multiple decimations from a single source
+    stream, continuing until the last decimated level contains fewer
+    than 500 points total.
+    """)
+    parser.add_argument("-u", "--url", action="store",
+                        default="http://localhost/nilmdb/",
+                        help="NilmDB server URL (default: %(default)s)")
+    parser.add_argument('-f', '--factor', action='store', default=4, type=int,
+                        help='Decimation factor (default: %(default)s)')
+    parser.add_argument("path", action="store",
+                        help='Path of base stream')
+    args = parser.parse_args(argv)
+
+    # Pull out info about the base stream
+    client = nilmdb.client.Client(args.url)
+
+    info = get_stream_info(client, args.path)
+    if not info:
+        raise Exception("path " + args.path + " not found")
+
+    meta = client.stream_get_metadata(args.path)
+    if "decimate_source" in meta:
+        print "Stream", args.path, "was decimated from", meta["decimate_source"]
+        print "You need to pass the base stream instead"
+        raise SystemExit(1)
+
+    # Figure out the type we should use for decimated streams
+    if 'int32' in info.layout_type or 'float64' in info.layout_type:
+        decimated_type = 'float64_' + str(info.layout_count * 3)
+    else:
+        decimated_type = 'float32_' + str(info.layout_count * 3)
+
+    # Now do the decimations until we have few enough points
+    factor = 1
+    while True:
+        print "Level", factor, "decimation has", info.rows, "rows"
+        if info.rows <= 500:
+            break
+        factor *= args.factor
+        new_path = "%s~decim-%d" % (args.path, factor)
+
+        # Create the stream if needed
+        new_info = get_stream_info(client, new_path)
+        if not new_info:
+            print "Creating stream", new_path
+            client.stream_create(new_path, decimated_type)
+
+        # Run the decimation as if it were run from the commandline
+        nilmtools.decimate.main(["-u", args.url,
+                                 "-f", str(args.factor),
+                                 info.path,
+                                 new_path])
+
+        # Update info using the newly decimated stream
+        info = get_stream_info(client, new_path)
+
+if __name__ == "__main__":
+    main()

src/filter.py

@@ -218,10 +218,9 @@ class Filter(object):
                 m += "  %s = %s\n" % (key, val)
                 m += "doesn't match desired data:\n"
                 m += "  %s = %s\n" % (key, wanted)
-                m += "Refusing to change it.  You can change the stream's "
-                m += "metadata manually, or\n"
-                m += "remove existing data from the stream, to prevent "
-                m += "this error.\n"
+                m += "Refusing to change it.  To prevent this error, "
+                m += "change or delete the metadata with nilmtool,\n"
+                m += "or remove existing data from the stream."
                 raise Exception(m)
         # All good -- write the metadata in case it's not already there
         self._client_dest.stream_update_metadata(self.dest.path, data)