title: numpy, mapping one array to parts of another
body: <p>lets say i have one array</p>
  
  <pre><code>    a = numpy.arange(8*6*3).reshape((8, 6, 3))
      #and another:
      l = numpy.array([[0,0],[0,1],[1,1]]) #an array of indexes to array "a"
      #and yet another:
      b = numpy.array([[0,0,5],[0,1,0],[1,1,3]])
  </code></pre>
  
  <p>where "l" and "b" are of equal length,
  and i want to say</p>
  
  <pre><code>    a[l] = b
  </code></pre>
  
  <p>such that a[0][0] becomes [0,0,5], a[0][1] becomes [0,1,0] etc.</p>
  
  <p>it seems to work fine when ive got one-dimensional arrays, but it gives me the error</p>
  
  <pre><code>    ValueError: array is not broadcastable to correct shape
  </code></pre>
  
  <p>when i try it with a 3-dimensional array.</p>