Struct LbmGpuSolver 

pub struct LbmGpuSolver {
    pub nx: u32,
    pub ny: u32,
    pub nz: u32,
    pub omega: f32,
    pub step_count: u64,
    /* private fields */
}

GPU-accelerated D3Q19 BGK LBM solver (requires wgpu-backend feature).

Uses WgpuBackendReal to dispatch the lbm_bgk_d3q19.wgsl shader with ping-pong buffers. Falls back gracefully when no GPU adapter is available.

Buffer layout

f_buf_a and f_buf_b are each sized 19 × nx × ny × nz × sizeof(f32). The params buffer holds [nx, ny, nz, omega_bits, 0u32] (5 × 4 bytes).

step() alternates which buffer is read (f_in) vs written (f_out).

Fields

nx: u32

Number of cells in X, Y, Z.

ny: u32

Number of cells in Y.

nz: u32

Number of cells in Z.

omega: f32

BGK relaxation frequency ω = 1/τ.

step_count: u64

Number of steps executed so far.

Implementations

impl LbmGpuSolver

pub fn new(nx: u32, ny: u32, nz: u32, omega: f32) -> Self

Create a new solver. Attempts to use a real GPU adapter; if none is available, falls back to the CPU LbmSimulation.

omega = 1/tau (e.g. 1.5 for τ = 2/3, giving ν = 1/18 in lattice units).

pub fn new_cpu(nx: u32, ny: u32, nz: u32, omega: f32) -> Self

Create directly with a CPU fallback (useful for testing without GPU).

pub fn is_gpu(&self) -> bool

Returns true if a real GPU backend is active.

pub fn step(&mut self) -> Result<(), GpuError>

Advance one BGK streaming+collision step.

pub fn read_density(&self) -> Vec<f32>

Download per-cell density ρ = Σᵢ fᵢ from the current read buffer.

Returns a Vec<f32> of length nx * ny * nz.

pub fn read_velocity(&self) -> Vec<[f32; 3]>

Download per-cell velocity [ux, uy, uz] from the current read buffer.

Returns a Vec<[f32; 3]> of length nx * ny * nz.