title: multiply numpy array of scalars by array of vectors
body: <p>I have a numpy array of vectors that I need to multiply by an array of scalars. For example:</p>
  
  <pre><code>&gt;&gt;&gt; import numpy
  &gt;&gt;&gt; x = numpy.array([0.1, 0.2])
  &gt;&gt;&gt; y = numpy.array([[1.1,2.2,3.3],[4.4,5.5,6.6]])
  </code></pre>
  
  <p>I can multiply individual elements like this:</p>
  
  <pre><code>&gt;&gt;&gt; x[0]*y[0]
  array([ 0.11,  0.22,  0.33])
  </code></pre>
  
  <p>but when I try and multiply the entire arrays by each other, I get:</p>
  
  <pre><code>&gt;&gt;&gt; x*y
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  ValueError: shape mismatch: objects cannot be broadcast to a single shape
  </code></pre>
  
  <p>I think this has to do with the broadcasting rules. What's the fastest way to multiply these two arrays element-wise with numpy?</p>