freeze get_variable

README.md

 # tensorpack
 Neural Network Toolbox on TensorFlow
 
-See some [examples](examples) to learn about the framework:
+Docs & tutorials should be ready within a month. See some [examples](examples) to learn about the framework:
 
 ### Vision:
 + [DoReFa-Net: train binary / low-bitwidth CNN on ImageNet](examples/DoReFa-Net)

tensorpack/tfutils/varreplace.py

@@ -7,7 +7,9 @@ import tensorflow as tf
 from tensorflow.python.ops import variable_scope
 from contextlib import contextmanager
 
-__all__ = ['replace_get_variable']
+__all__ = ['replace_get_variable', 'freeze_get_variable']
+
+_ORIG_GET_VARIABLE = tf.get_variable
 
 
 @contextmanager
@@ -20,3 +22,16 @@ def replace_get_variable(fn):
     yield
     tf.get_variable = old_getv
     variable_scope.get_variable = old_vars_getv
+
+
+def freeze_get_variable():
+    """
+    Return a contextmanager, where all variables returned by
+    `get_variable` will have no gradients.
+    """
+    old_get_variable = tf.get_variable
+
+    def fn(name, shape=None, **kwargs):
+        v = old_get_variable(name, shape, **kwargs)
+        return tf.stop_gradient(v)
+    return replace_get_variable(fn)