In clf->Array.py, I created a temp variable named 's' that stores all string concatenations while the routines 'for' loop is iterated. Once the 'for' loop is finished, I set the xml element's text to the variable 's'. Previously the element's text attribute was successively appended to. This resulted in a massive allocaion of memory and an ever growing slowdown.

I created a new function called xmlWrite in ProcessList.py. This function does not prettify the document string (as it is very close to being prettified). This 'prettyXmlWrite' function takes 10 minutes on a Mac i7 laptop. I will want to check, but I can't imagine prettified xml being operationally critical.