[ADMB Users] inv_cumd_gamma parameters

[Mollie Brooks]

Hi,
I'm guessing Hans is the best person to ask, but I thought this could  
benefit others as well.

I'm having trouble relating inv_cumd_gamma() to the gamma distribution  
I know which has 2 parameters. I've seen the example at
http://otter-rsch.com/admbre/examples/gamma/gamma.html
which uses it as follows:
   theta*inv_cumd_gamma(z, 1/theta)

If z is an observation of the cumulative density, and inv_cumd_gamma  
should map z back to the gamma distribution, then I'm wondering why  
the gamma distribution only has one parameter. Do I need to do another  
transformation to get k in there?

thanks,
Mollie