possible error in generalized fluid equations

[akshay-ghalsasi]

Hi,

I was checking in the int perturbations_derivs function in the perturbation.c module

For the generalized fluid perturbation the equation thats written is

dy[pv->index_pt_delta_fld] = -(1+w_fld)*(y[pv->index_pt_theta_fld]+metric_continuity) -3.*(cs2-w_fld)*a_prime_over_a*y[pv->index_pt_delta_fld] -9.*(1+w_fld)*(cs2-ca2)*a_prime_over_a*a_prime_over_a*y[pv->index_pt_theta_fld]/k2;

I believe the second term in the RHS should be -3(1+cs2) instead of -3(cs2 - w_fld) according to A9 in https://arxiv.org/pdf/astro-ph/9801234.pdf

For e.g. for a scalar field that term should be 6a_prime_over_adelta_rho_fld where the 6 comes for 3(1+cs2)

Please let me know if you agree.

Thanks, Akshay

[akshay-ghalsasi]

never mind I see the that its delta_fld and not delta_rho_fld

Akshay