Fix unique1d for empty sets. Closes r208.

1 files changed, 10 insertions, 6 deletions

diff --git a/numpy/lib/arraysetops.py b/numpy/lib/arraysetops.py
index c7449eb12..a12185b41 100644
--- a/numpy/lib/arraysetops.py
+++ b/numpy/lib/arraysetops.py
@@ -48,20 +48,24 @@ def ediff1d(ary, to_end = None, to_begin = None):
 ##
 # 01.11.2005, c
 # 02.11.2005
-def unique1d( ar1, retindx = False ):
+def unique1d(ar1, retindx=False):
     """Unique elements of 1D array. When ret_indx is True, return also the
     indices indx such that ar1.flat[indx] is the resulting array of unique
     elements."""
+    ar = numpy.asarray(ar1).ravel()
+    if ar.size == 0:
+        if retindx: return numpy.empty(0, numpy.bool), ar
+        else: return ar
+    
     if retindx:
-        ar = numpy.array(ar1).ravel()
         perm = ar.argsort()
         aux = ar.take(perm)
-        flag = ediff1d( aux, 1 ) != 0
+        flag = ediff1d(aux, 1) != 0
         return perm.compress(flag), aux.compress(flag)
+    
     else:
-        ar = numpy.array( ar1 ).flatten()
-        ar.sort()
-        return ar.compress( ediff1d( ar, 1 ) != 0)
+        ar = numpy.array(sorted(ar))
+        return ar.compress(ediff1d(ar, 1) != 0)
 
 ##
 # 01.11.2005, c