title: How to do multiply each row of a matrix by different scalar in tensorflow
body: <p>Suppose I have a matrix <code>A</code> of dimension <code>(N,5)</code> and a vector <code>v</code> of dimension <code>(N,1)</code>. Is there any efficient way to obtain a  new matrix <code>B</code> of dimension <code>(N,5)</code> such that each row <code>B[i,:]=v[i]*A[i,:]</code> in tensorflow?</p>
  
  <p>The known operation <code>tf.matmul</code> and <code>tf.multiply</code> don't support these kind of operations.</p>