title: How to build a tensor from 2 scalars in Tensorflow?
body: <p>I have two scalars resulting from the following operations:
  <code>a = tf.reduce_sum(tensor1)</code>, <code>b = tf.matmul(tf.transpose(tensor2), tensor3)</code> this is a dot product since <code>tensor2</code> and <code>tensor3</code> have the same dimensions (1-D vectors). Since these tensors have shape <code>[None, dim1]</code> it becomes difficult to deal with the shapes.</p>
  
  <p>I want to build a tensor that has shape (2,1)  using <code>a</code> and <code>b</code>.</p>
  
  <p>I tried <code>tf.Tensor([a,b], dtype=tf.float64, value_index=0)</code> but raises the error</p>
  
  <p><code>TypeError: op needs to be an Operation: [&lt;tf.Tensor 'Sum_5:0' shape=() dtype=float32&gt;, &lt;tf.Tensor 'MatMul_67:0' shape=(?, ?) dtype=float32&gt;]</code></p>
  
  <p>Any easier way to build that tensor/vector?</p>