add constraints and regularizers modules

keras/constraints.py

@@ -0,0 +1,16 @@
+from __future__ import absolute_import
+import theano
+import theano.tensor as T
+import numpy as np
+
+def maxnorm(m=2):
+    def maxnorm_wrap(p):
+        norms = T.sqrt(T.sum(T.sqr(p), axis=0))
+        desired = T.clip(norms, 0, m)
+        p = p * (desired / (1e-7 + norms))
+        return p
+    return maxnorm_wrap
+
+def nonneg(p):
+    p *= T.ge(p,0)
+    return p

keras/regularizers.py

@@ -0,0 +1,19 @@
+from __future__ import absolute_import
+import theano
+import theano.tensor as T
+import numpy as np
+
+def l1(lam=.01):
+    def l1wrap(g,p):
+        g += T.sgn(p) * lam
+        return g
+    return l1wrap
+
+def l2(lam=.01):
+    def l2wrap(g,p):
+        g += p * lam
+        return g
+    return l2wrap
+
+def ident(g,*l):
+    return g