title: Tensorflow: searching for an op supporting vector- tensor broadcasting
body: <p>I am trying to achieve something like:</p>
  
  <p>inputs: </p>
  
  <ol>
  <li>x: a vector with length n, [x1,x2,...,xn], elements (xi, i=1,2,...n) are scalars.</li>
  <li>T: a tensor with length n in its first dimension, [t1,t2,...tn], elements (ti, i=1,2,..,n) are tensors with rank 3.</li>
  </ol>
  
  <p>return: a tensor, <code>[x1*t1, x2*t2, ... xn*tn]</code>.</p>
  
  <p>I know this can be achieved by <code>tf.stack([x[i]*T[i] for i in range(n)])</code>, wonder if there are any elegant approaches without iteration.</p>