wip3m/notebooks/3_constants.ipynb

Tristan Hoellinger
Institut d'Astrophysique de Paris tristan.hoellinger@iap.fr

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import numpy as np

In [5]:

L = 256
N = 512
Np = 256
Npm = 512
min_k_1D = 2 * np.pi / L
min_k = 2 * np.pi / L / np.sqrt(3)
nyquist = np.pi * N / L
nyquist_PM = np.pi * Npm / L
nyquist_particles = np.pi * Np / L
epsilon = 0.03 * L / Np
particle_length = 2*epsilon
xs = 1.25 * L / Npm
xr = 4.5 * xs
particle_wavenumber = 2*np.pi / particle_length
xs_inv = 2*np.pi / xs
xr_inv = 2*np.pi / xr
print(f"Min k (1D): {min_k_1D:.3f} h/Mpc")
print(f"Min k: {min_k:.3f} h/Mpc")
print(f"Nyquist ('particles grid'): {nyquist_particles:.2f} h/Mpc")
print(f"Nyquist (density grid): {nyquist:.2f} h/Mpc")
print(f"Nyquist (PM grid): {nyquist_PM:.2f} h/Mpc")
print(f"Particle wavenumber: {particle_wavenumber:.2f} h/Mpc")
print(f"Split wavenumber: {xs_inv:.2f} h/Mpc")
print(f"Short-range reach: {xr_inv:.2f} h/Mpc")

Min k (1D): 0.025 h/Mpc
Min k: 0.014 h/Mpc
Nyquist ('particles grid'): 3.14 h/Mpc
Nyquist (density grid): 6.28 h/Mpc
Nyquist (PM grid): 6.28 h/Mpc
Particle wavenumber: 104.72 h/Mpc
Split wavenumber: 10.05 h/Mpc
Short-range reach: 2.23 h/Mpc

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