Multiprocessing nested python loops
<p>To improve my code which has one heavy loop I need a speed up. How can I implement multiprocessing for a code like this? (a is typical of size 2 and l up to 10)</p>

<pre><code>for x1 in range(a**l):
    for x2 in range(a**l):
        for x3 in range(a**l):
            output[x1,x2,x3] = HeavyComputationThatIsThreadSafe1(x1,x2,x3)
</code></pre>