Monday, 07/24: Writing a pm-code - AIP

More documents

Recommendations

Info

¡ ¡ ¡ £ ¢ ¢ £ ¢ ¢ £ ¢ ¢ ¡ ¡ ¡ ¢ £ '&( & ¢ £ .-0/ & ¢ £ ¡ ¡ ¡ ¡ ¡ ¡ PM: main code blocks 23 PM interpolation kernels in real and Fourier space. Adopted from PM lectures by M.Gross 3-9 the density assignment wider in configuration space. ¤¦¥¨§© ¡ ¡ ¤! #"$ % ¡ ¡ ¤*),+ % ¡ ¡
PM: main code blocks 24 Implementing CIC interpolation The choice of interpolation scheme is a tradeoff between accuracy and computational expense. The CIC scheme is both relatively cheap and accurate and is most commonly used in PM codes. I will now describe how to implement it (you can start coding with the simpler NGP scheme and upgrade it to CIC later when your code is tested). Consider the density assignment for a particle with coordinates {x p , y p , z p } The cell containing the particle will have indices of i = [x p ]; j = [y p ]; k = [z p ], where [x] is the integer floor function (equivalent to Fortran’s int). Let’s assume that cell centers are at {x c , y c , z c } = {i, j, k} (note that in internal units cell size ∆x = 1, this will be implicitly assumed below). This is a matter of convention, but once chosen the convention should be consistent throughout the code.
Page 1 and 2: Writing a PM code Andrey Kravtsov a
Page 3 and 4: equations I 2 Cosmological simulati
Page 5 and 6: N-body approach 4 Cosmological simu
Page 7 and 8: particle initial conditions 6 Cosmo
Page 9 and 10: equations of gasdynamics 8 Cosmolog
Page 11 and 12: equations summary 10 • Baryonic g
Page 13 and 14: dissipationless simulations 12 Part
Page 15 and 16: Model equations 14 Model equations
Page 17 and 18: Model equations 16 The quantities w
Page 19 and 20: Model equations 18 In dimensionless
Page 21 and 22: PM: main code blocks 20 Density Ass
Page 23: PM: main code blocks 22 In practice
Page 27 and 28: PM: main code blocks 26 Solving the
Page 29 and 30: PM: main code blocks 28 ⇒ Given a
Page 31 and 32: PM: main code blocks 30 After n tim
Page 33 and 34: Zeldovich approximation (ZA) 32 Zel
Page 35 and 36: A test problem: 1D collapse of a pl
Page 41 and 42: Setting up cosmological ICs 40 The
Page 43 and 44: Setting up cosmological ICs 42 Appl
Page 45 and 46: project summary 44 Project summary
Page 47 and 48: References and links 46 PM in cosmo
Page 49 and 50: References and links 48 • Michael

Monday, 07/24: Writing a pm-code - AIP

Create successful ePaper yourself

Delete template?

Save as template?