Solar PV output equation

I have found a equation of solar PV output. it's used to predict the PV array output power. my question: is this equation is applicable for SAM also or what is the background calculus of SAM in order to predict the solar array output. the details of the equation is attached here. Pls find the attachment

Hello,
When you model a PV system in SAM, you choose from a few different options for how SAM will model the system. The equations that SAM uses depend on the options you choose.
For a description of the different PV models in SAM, see the references on the Performance Models page.
We are working on a reference manual for SAM that describes the details of the PV model. It should be ready for publication this winter (2013/2014).
Best regards,

Paul.