[mesa-users] density partial

[Josiah Schwab]

Hi Ehsan,

> I need to calculate the partial derivative of density
> w.r.t. temperature at constant pressure and constant mu. looking into
> the public pointers in star_data.inc did not help me.  Can any of you
> kindly help me calculate that?

The basic eos (see eos/public/eos_def.f), gives you

,----
| integer, parameter :: i_chiRho = 5 
|       ! dlnP_dlnRho at constant T
| integer, parameter :: i_chiT = 6 
|       ! dlnP_dlnT at constant Rho
`----

and then I think you can derive dlnRho_dlnT at constant P from those
using an identity like

http://en.wikipedia.org/wiki/Triple_product_rule

Hope that helps,
Josiah