Power spectrum evaluation with fixed mesh

vrastil / FastSim

Other

0 stars 1 forks source link

Power spectrum evaluation with fixed mesh #15

Closed vrastil closed 6 years ago

vrastil commented 7 years ago

In order to have compatible results for various simulations, the power spectrum evaluation should be performed on the same grid. N_m = 1024

vrastil commented 7 years ago

fixing in branch fix_mesh_pwr

vrastil commented 7 years ago

now working for Zel'dovich change of m = pow(Ng, 3) to m = pow(Ng, 1.5)*pow(Ng_pwr, 1.5)

Why? need to investigate exact units and \rho_avg = 1

Done

SOLUTION: m = pow(Ng_pwr, 3) - justified from overdensity definiton, no need for \rho_avg = 1

Extra normalization of power spectra Pk *= pow(Ng, 3) - probably due to FFT definiton and FT of gaussian random field (n(x, \sigma = 1) -> sqrt(2*N) n(k, \sigma = 1)

vrastil commented 7 years ago

allow power_spectrum nesh to be smaller than potential-force mesh

problem for FP and FP_pp which are using power_aux as temporary store of potential

Solve with resizing of Mesh? Use std::vector instead of new?

WON`T FIX: In order to have proper resolution one should have inequalities

N_a >= N_p >= N_p