Add functions to generate 'unpacked matches' in a Catalog.

python/hsc/pipe/base/matches.py

@@ -0,0 +1,109 @@
+import os.path
+import lsst.afw.table as afwTable
+
+def copySchema(schema, target, targetPrefix=None, sourcePrefix=None):
+    """Return a deep copy the provided schema
+
+    If sourcePrefix is set, only copy those keys that have that prefix.
+    If targetPrefix is set, add that to the key name.
+    """
+    existing = set(target.getNames())
+    for keyName in schema.getNames():
+        if sourcePrefix is not None:
+            if not keyName.startswith(sourcePrefix):
+                continue
+            keyNameFix = keyName[len(sourcePrefix):]
+        else:
+            keyNameFix = keyName
+        if keyNameFix in existing:
+            continue
+        field = schema.find(keyName).field
+        typeStr = field.getTypeString()
+        fieldDoc = field.getDoc()
+        fieldUnits = field.getUnits()
+        if typeStr in ("ArrayF", "ArrayD", "CovF", "CovD"):
+            fieldSize = field.getSize()
+        else:
+            fieldSize = None
+
+        target.addField((targetPrefix if targetPrefix is not None else "") + keyNameFix,
+                        type=typeStr, doc=fieldDoc, units=fieldUnits, size=fieldSize)
+    return target
+
+def copyCatalog(catalog, target, sourceSchema=None, targetPrefix=None, sourcePrefix=None):
+    """Copy entries from one Catalog to another.
+
+    If sourcePrefix is set, only copy those keys that have that prefix.
+    If targetPrefix is set, add that to the key name.
+    """
+    if sourceSchema is None:
+        sourceSchema = catalog.schema
+
+    targetSchema = target.schema
+    target.reserve(len(catalog))
+    for i in range(len(target), len(catalog)):
+        target.addNew()
+
+    if len(catalog) != len(target):
+        raise RuntimeError("Length mismatch: %d vs %d" % (len(catalog), len(target)))
+
+    sourceKeys = []
+    targetKeys = []
+    for k in sourceSchema.getNames():
+        if sourcePrefix is not None:
+            if not k.startswith(sourcePrefix):
+                continue
+            kFix = k[len(sourcePrefix):]
+        else:
+            kFix = k
+        sourceKeys.append(sourceSchema.find(k).key)
+        targetKeys.append(targetSchema.find((targetPrefix if targetPrefix is not None else "") + kFix).key)
+
+    for rFrom, rTo in zip(catalog, target):
+        for kFrom, kTo in zip(sourceKeys, targetKeys):
+            rTo.set(kTo, rFrom.get(kFrom))
+
+    return target
+
+def matchesToCatalog(matches, matchMeta):
+    """Denormalise matches into a Catalog of "unpacked matches" """
+
+    refSchema = matches[0].first.getSchema()
+    srcSchema = matches[0].second.getSchema()
+
+    mergedSchema = copySchema(refSchema, afwTable.Schema(), targetPrefix="ref.")
+    mergedSchema = copySchema(srcSchema, mergedSchema, targetPrefix="src.")
+    distKey = mergedSchema.addField("distance", type=float, doc="Distance between ref and src")
+
+    mergedCatalog = afwTable.BaseCatalog(mergedSchema)
+    copyCatalog([m.first for m in matches], mergedCatalog, sourceSchema=refSchema, targetPrefix="ref.")
+    copyCatalog([m.second for m in matches], mergedCatalog, sourceSchema=srcSchema, targetPrefix="src.")
+    for m, r in zip(matches, mergedCatalog):
+        r.set(distKey, m.distance)
+
+    # obtaining reference catalog name
+    catalogName = os.path.basename(os.getenv("ASTROMETRY_NET_DATA_DIR").rstrip('/'))
+    matchMeta.add('REFCAT', catalogName)
+    mergedCatalog.getTable().setMetadata(matchMeta)
+
+    return mergedCatalog
+
+def matchesFromCatalog(catalog, sourceSlotConfig=None, prefix=""):
+    """Generate a list of ReferenceMatches from a Catalog of "unpacked matches" """
+    refSchema = copySchema(catalog.schema, afwTable.SimpleTable.makeMinimalSchema(), sourcePrefix="ref.")
+    refCatalog = afwTable.SimpleCatalog(refSchema)
+    copyCatalog(catalog, refCatalog, sourcePrefix="ref.")
+
+    srcSchema = copySchema(catalog.schema, afwTable.SourceTable.makeMinimalSchema(), sourcePrefix="src.")
+    srcCatalog = afwTable.SourceCatalog(srcSchema)
+    copyCatalog(catalog, srcCatalog, sourcePrefix="src.")
+
+    if sourceSlotConfig is not None:
+        sourceSlotConfig.setupTable(srcCatalog.table, prefix=prefix)
+
+    matches = []
+    distKey = catalog.schema.find("distance").key
+    for ref, src, cat in zip(refCatalog, srcCatalog, catalog):
+        matches.append(afwTable.ReferenceMatch(ref, src, cat[distKey]))
+
+    return matches