Finding the break in data from a piecewise function

Greetings,

I'm performing research t开发者_如何学Pythonhat will help determine the size of observed space and the time elapsed since the big bang. Hopefully you can help!

I have bilinear data on which I want to perform two linear regressions. There is a point at which the slope and intercept change, and I need to (write a program to) find this point.

Thoughts?

There was a paper on this a few years ago by Joo and Qiu at Minnesota: http://pubs.amstat.org/doi/pdf/10.1198/tech.2009.07163