confirmed transiting exoplanets (www.exoplanet.org). Of these planets, several dozen have spectra that have been observed, either through broadband photometry from instruments like the Spitzer Infrared Array Camera (IRAC) (Knutson et al. 2007; 2008; Harrington et al. 2006; 2007; Stevenson et al. 2011) or higher resolution spectroscopy from the Hubble Space Telescope (HST) Near Infrared Camera and Multi-Object Spectrometer (NICMOS) (Swain et al. 2009a; 2009b), Spitzer Infrared Spectrometer (IRS) (Grillmair et al. 2007; 2008), and recently, from ground based instruments (Swain et al. 2010; Mandel et al. 2011). Although the spectra are of low resolution ($R= \lambda/\Delta \lambda \sim 5-50$) and low signal to noise (S/N $\le 10$), they nevertheless provide useful information about the temperature and composition of the exoplanetary atmospheres (Tinetti et al. 2007; 2010; Madahusudhan & Seager 2009; etc.). A typical approach to retrieving this information is to match the data set with forward models by manually tuning the model abundances and temperatures, until a possible best fit is obtained (Tinetti et al. 2007; 2011; Swain et al. 2009a; 2009b). This approach does not provide an optimal solution to the atmospheric state; furthermore, it can be cumbersome and is susceptible to multiple degeneracies (Tinetti et al. 2007; Sing 