title: Cannot make array in using tensorflow
body: <p>In feeding batch_xs to x, I reshaped batch_xs, for BATCH_SIZE is 1.
  Here is my source.
  I'm not sure what is making the ValueError.</p>
  
  <pre><code>with tf.name_scope("input") as scope:
      x = tf.placeholder(tf.float32, shape=[1, 784])
  
  BATCH_SIZE = 1
  DROP_OUT_RATE = 0.4
  EPOCH = 1
  MEMORIZE = 10
  accuracy_array = []
  loss = tf.nn.l2_loss(y - x) / BATCH_SIZE
  train_step = tf.train.AdamOptimizer(1e-4).minimize(loss)
  
  mnist = input_data.read_data_sets('MNIST_data', one_hot=True)
  mnist_list = make_mnist_train_list(55000, 10)
  test_list = make_mnist_test_list(5000, 10)
  sess = tf.Session()
  sess.run(tf.initialize_all_variables())
  
  for i in range(EPOCH):
      for j in range(5500/BATCH_SIZE):
          batch_xs = tf.reshape(mnist_list[0][j*BATCH_SIZE:j*BATCH_SIZE+1], [1, 784])
          sess.run(train_step, feed_dict={x: batch_xs, keep_prob: (1.0 - DROP_OUT_RATE), r_keep_prob: (1.0 - DROP_OUT_RATE)})
          if (i +1)% MEMORIZE == 0:
              accuracy_array.append(loss.eval(session=sess, feed_dict={x: batch_xs, keep_prob: 1.0, r_keep_prob: 1.0}))
              print(accuracy_array[ int(math.floor((i+1)/MEMORIZE -1))])
  </code></pre>
  
  <p>This gives me the Value error, which doesn't make sense to me.</p>
  
  <p>ValueError: Argument must be a dense tensor</p>