Fix :summary_test by avoiding scatter_add (#303)
Fix :summary_test by avoiding scatter_add (#303)

Per issue tensorflow/tensorflow#11856, a variable cannot be read from
directly after it is merely initialized in a TensorFlow graph. We must
instead use read_value to retrieve its value. This means that using
tf.scatter_add is problematic because it only accepts a single mutable
tensor (tf.Variable) that is both written to and read from.

Hence, we avoid using tf.scatter_add and re-implement its logic using
tf.gather and tf.scatter_update. We also use read_value() to retrieve
the values of variables throughout the summary logic.
qiuminxu/tensorboard,tensorflow/tensorboard,agrubb/tensorboard,qiuminxu/tensorboard,ioeric/tensorboard,ioeric/tensorboard,francoisluus/tensorboard-supervise,tensorflow/tensorboard,qiuminxu/tensorboard,tensorflow/tensorboard,tensorflow/tensorboard,tensorflow/tensorboard,qiuminxu/tensorboard,agrubb/tensorboard,francoisluus/tensorboard-supervise,agrubb/tensorboard,francoisluus/tensorboard-supervise,ioeric/tensorboard,agrubb/tensorboard,tensorflow/tensorboard,francoisluus/tensorboard-supervise,francoisluus/tensorboard-supervise,qiuminxu/tensorboard,tensorflow/tensorboard,ioeric/tensorboard,qiuminxu/tensorboard,ioeric/tensorboard,ioeric/tensorboard,francoisluus/tensorboard-supervise,agrubb/tensorboard,agrubb/tensorboard