# HG changeset patch
# User Olivier Delalleau <delallea@iro>
# Date 1243995964 14400
# Node ID c60ad32e1f40bbe5795922d03705be01a4abc8ef
# Parent  2a30f22ef7ffe4835e41fe139bb40e8078b40f92
Fix to the 'by_pair' corruption pattern

diff -r 2a30f22ef7ff -r c60ad32e1f40 pylearn/algorithms/sandbox/DAA_inputs_groups.py
--- a/pylearn/algorithms/sandbox/DAA_inputs_groups.py	Tue Jun 02 14:40:43 2009 -0400
+++ b/pylearn/algorithms/sandbox/DAA_inputs_groups.py	Tue Jun 02 22:26:04 2009 -0400
@@ -316,11 +316,11 @@
             mask = self.random.binomial(T.shape(self.input), 1, 1 - self.noise_level)
         elif self.corruption_pattern == 'by_pair':
             shape = T.shape(self.input)
-            scale = numpy.ones(2)
-            scale[1] = 2
-            shape = shape / scale
+            # Do not ask me why, but just doing "/ 2" does not work (there is
+            # a bug in the optimizer).
+            shape = T.stack(shape[0], (shape[1] * 2) / 4)
             mask = self.random.binomial(shape, 1, 1 - self.noise_level)
-            mask = T.hstack((mask, mask))
+            mask = T.horizontal_stack(mask, mask)
         else:
             raise ValueError('Unknown value for corruption_pattern: %s'
                     % self.corruption_pattern)