# HG changeset patch
# User Joseph Turian <turian@iro.umontreal.ca>
# Date 1215804401 14400
# Node ID f63dfb0ac7dc455b015367454160eef03638d075
# Parent  35b858a1d4fd4059238dd649a6d825a2bbe93a20
Added cost functions

diff -r 35b858a1d4fd -r f63dfb0ac7dc cost.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cost.py	Fri Jul 11 15:26:41 2008 -0400
@@ -0,0 +1,9 @@
+"""
+Cost functions.
+"""
+
+def quadratic(target, output, axis=1):
+    return T.mean(T.sqr(target - output), axis)
+
+def cross_entropy(target, output, axis=1):
+    return -T.mean(target * T.log2(output) + (1 - target) * T.log2(1 - output), axis=axis)