# HG changeset patch
# User James Bergstra <bergstrj@iro.umontreal.ca>
# Date 1305730310 14400
# Node ID ddda8d93c162217426daae4e4dd7281c15e2c48f
# Parent  281efa9a4463c1d12ff4a1cc1b5832711beccc4f
dtype tweaks in sgd

diff -r 281efa9a4463 -r ddda8d93c162 pylearn/gd/sgd.py
--- a/pylearn/gd/sgd.py	Wed May 18 10:51:11 2011 -0400
+++ b/pylearn/gd/sgd.py	Wed May 18 10:51:50 2011 -0400
@@ -1,6 +1,6 @@
 """A stochastic gradient descent minimizer.
 """
-
+import numpy
 import theano
 
 def sgd_updates(params, grads, stepsizes):
@@ -35,11 +35,11 @@
         momentum = [momentum for p in params]
     if len(params) != len(grads):
         raise ValueError('params and grads have different lens')
-    headings = [theano.shared(p.get_value(borrow=False)*0) for p in params]
+    headings = [theano.shared(numpy.zeros_like(p.get_value(borrow=True))) for p in params]
     updates = []
     for s, p, gp, m, h in zip(stepsizes, params, grads, momentum, headings):
         updates.append((p, p + s * h))
-        updates.append((h, m*h - (1-m)*gp))
+        updates.append((h, m*h - (1.0-m)*gp))
     return updates