I am trying to generate a numerical initial condition for a PDE that looks like this: it is a Bravais lattice, with a gaussian at each site (in 2D). This is not difficult to do by hand for a square lattice with two atoms per unit cell, for example: using Plots const N = 256 dx = 1/143 dy = dx x =…

In CellListMap.jl I have a function that replicates the a periodic system according to the unit cell matrix, it works like this: julia> using CellListMap julia> x = SVector{2,Float64}[ [0,0], [0,1], [0.5,0.5] ]; julia> CellListMap.replicate_system!(x,[ 1 0 ; 0.5 1 ],(0:5,0:5)); # replicate (updat…

[image] ash: This code is very clunky and ugly Just writing a loop over unit cells, accumulating one or more gaussians per unit cell, seems a lot easier than fiddling with broadcasting.

Thank you all for the suggestions. I moved over to accumulating gaussians per unit cell instead of broadcasting as @stevengj suggested and used LightLattices.jl. Here’s a script I spent a few hours hacking together and testing (most of the time went to figuring out the geometry and making sure the p…

I’d you just remind the bottom and right bits, it would tile properly.

[image] ash: if type==:Square I don’t understand why you need a different loop for each lattice type. Can’t you just specify the Bravais lattice by two primitive lattice vectors, and then have an array of displacements per unit cell for each “atom”? (e.g. honeycomb is a hexagonal lattice wit…

Annoyances with boundaries are so much nicer to deal with in Fourier space, so I’d recommend doing that (you’re probably going to do FFTs later anyway…). Also seconding @stevengj 's comment on the lattice construction. Here’s an example that does that, piggybacking on the routine in our code DFTK ( h…

Oh I see you wanted the plot in cartesian coordinates; then the above will not do what you want, because it’ll plot it in the crystal coordinate system (the change of variables is x_cart=lattice*x_crystal): you’d have to either do the plot in these skewed coordinates, or map back to real space and i…

By the way, if you are dealing with a Bravais Lattice (single atom per unit cell), then there is a special type of unit cell called TrivialCell, which emulates a single atom with zero displacement. So, if you want to specify a Bravais lattice, you can simply drop unit cell from Regular Lattice cons…

Bravais lattice with a gaussian at every site

General Usage

rafael.guerra January 23, 2022, 2:24pm 3

FWIW, the packages indicated in this thread handle Bravais lattices, and there is also the PWDFT.jl package which deals with them.

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Bravais lattice with a gaussian at every site

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