GLAM code and simulations
GLAM simulations are done using a Particle-Mesh (PM) code. Desciption of the code is here. Here is a short description:
As any vanilla PM code, GLAM repeateadly makes three steps to evolve particles:
Using positions of Np particles to obtain the density ρ at the nodes of an homogenous 3D- mesh that covers the computational domain of size Box,
Solve the Poisson equation on the mesh of size Ngrid using FFT technique
Advance the particles to a new moment of time using a leap-frog integration scheme. For most of time steps GLAM uses a constant da stepping. However, once in a while the value of da increases 1.5 times.