diff --git a/bob/learn/misc/__init__.py b/bob/learn/misc/__init__.py
index bae1acf977d226b33e12046bd6e1c67d10cab0ad..a4e9098b449607bb38f348861b95e9d883f93bf4 100644
--- a/bob/learn/misc/__init__.py
+++ b/bob/learn/misc/__init__.py
@@ -12,6 +12,22 @@ from ._old_library import *
 from . import version
 from .version import module as __version__
 
+
+def ztnorm_same_value(vect_a, vect_b):
+  """Computes the matrix of boolean D for the ZT-norm, which indicates where
+     the client ids of the T-Norm models and Z-Norm samples match.
+
+     vect_a An (ordered) list of client_id corresponding to the T-Norm models
+     vect_b An (ordered) list of client_id corresponding to the Z-Norm impostor samples
+  """
+  import numpy
+  sameMatrix = numpy.ndarray((len(vect_a), len(vect_b)), 'bool')
+  for j in range(len(vect_a)):
+    for i in range(len(vect_b)):
+      sameMatrix[j, i] = (vect_a[j] == vect_b[i])
+  return sameMatrix
+
+
 def get_config():
   """Returns a string containing the configuration information.
   """