title: understand np.matmul on 1D vectors
body: <pre><code>a = [1, 2, 3]
  b = [10, 10, 10]
  </code></pre>
  
  <p>np.matmul(a, b) gives 60 as the result.</p>
  
  <p>How does numpy multiply (3,) and (3,) dimension and returns the dot product not outer product (3 * 3) or throw an error "dimension not matching"?</p>