# HG changeset patch
# User Xavier Glorot <glorotxa@iro.umontreal.ca>
# Date 1252100255 14400
# Node ID f1a29c772210ba7c35b96c1efbbe950b28fd77f0
# Parent  2333cd78f5745918a85ed41b4bdcd2a325d28f79
add a tanh2 activation function DAA_input_groups

diff -r 2333cd78f574 -r f1a29c772210 pylearn/algorithms/sandbox/DAA_inputs_groups.py
--- a/pylearn/algorithms/sandbox/DAA_inputs_groups.py	Wed Sep 02 18:28:37 2009 -0400
+++ b/pylearn/algorithms/sandbox/DAA_inputs_groups.py	Fri Sep 04 17:37:35 2009 -0400
@@ -93,6 +93,10 @@
 def tanh_act(x):
     return theano.tensor.tanh(x/2.0)
 
+#divide per 2 is a bad idea with many layers... we lose the std of U*x
+def tanh2_act(x):
+    return theano.tensor.tanh(x)
+
 def softsign_act(x):
     return x/(1.0 + T.abs_(x))
 
@@ -112,6 +116,12 @@
     XS = T.xlogx.xlogx((target+1)/2.0) + T.xlogx.xlogx(1-(target+1)/2.0)
     return -T.mean(T.sum(XE-XS, axis=sum_axis),axis=mean_axis)
 
+def tanh2_cross_entropy(target, output_act, mean_axis, sum_axis):
+    XE = (target+1)/2.0 * (- T.log(1 + T.exp(- 2*output_act))) + \
+            (1 - (target+1)/2.0) * (- T.log(1 + T.exp( 2*output_act)))
+    XS = T.xlogx.xlogx((target+1)/2.0) + T.xlogx.xlogx(1-(target+1)/2.0)
+    return -T.mean(T.sum(XE-XS, axis=sum_axis),axis=mean_axis)
+
 def softsign_cross_entropy(target, output_act, mean_axis, sum_axis):
     newact = ((output_act/(1.0 + T.abs_(output_act)))+1)/2.0
     XE = (target+1)/2.0 * T.log(newact) + (1 - (target+1)/2.0) * T.log(1 - newact)
@@ -125,6 +135,8 @@
         return tanh_cross_entropy(target, output_act, mean_axis, sum_axis)
     if act == 'softsign_act':
         return softsign_cross_entropy(target, output_act, mean_axis, sum_axis)
+    if act == 'tanh2_act':
+        return tanh2_cross_entropy(target, output_act, mean_axis, sum_axis)
     assert False
 
 def quadratic(target, output, act, mean_axis = 0):
@@ -193,10 +205,10 @@
         self.corruption_pattern = corruption_pattern
         self.blockgrad = blockgrad
         
-        assert hid_fn in ('sigmoid_act','tanh_act','softsign_act')
+        assert hid_fn in ('sigmoid_act','tanh_act','softsign_act','tanh2_act')
         self.hid_fn = eval(hid_fn)
         
-        assert rec_fn in ('sigmoid_act','tanh_act','softsign_act')
+        assert rec_fn in ('sigmoid_act','tanh_act','softsign_act','tanh2_act')
         self.rec_fn = eval(rec_fn)
         self.rec_name = rec_fn
         
@@ -530,7 +542,7 @@
         self.corruption_pattern = corruption_pattern
         self.blockgrad = blockgrad
         
-        assert act_reg in ('sigmoid_act','tanh_act','softsign_act')
+        assert act_reg in ('sigmoid_act','tanh_act','softsign_act','tanh2_act')
         self.act_reg = eval(act_reg)
         
         print '\t**** StackedDAAig.__init__ ****'
@@ -909,7 +921,7 @@
         else: 
             if typeup == 'total':
                 if layer == 'all':
-                    cost[-1] = inst.totalupdate[-1](*data[-1])
+                    cost[-1] = inst.totalupdate[-2](*data[-1])
                 else:
                     cost[layer] = inst.totalupdate[layer](*data[layer])
             else: