eos
eos(gamma=1.6666666666667)
Returns the symbolic ideal-gas specific internal energy of the network, built
from the network's total number density (ntot) and mass density (rho):
\[ e = \dfrac{n_\mathrm{tot}\, k_B\, T_\mathrm{gas}}{\rho\,(\gamma - 1)} \quad [\mathrm{erg\,g^{-1}}] \]
where \(k_B\) is the Boltzmann constant in CGS units, \(T_\mathrm{gas}\) is the
tgas symbol, and \(\gamma\) is the adiabatic index. The code generator uses
this expression to form the temperature column of the Jacobian via the chain
rule \(\partial \dot{x} / \partial e = (\partial \dot{x} / \partial T) / (\partial e / \partial T)\).
Parameters
- gamma : float, optional
- Adiabatic index. Default
5/3 ≈ 1.6̄(monoatomic ideal gas).
Returns
- sympy.Expr
- Symbolic specific internal energy in CGS units (erg/g).