Struct DeviceResidentPcgInput 

pub struct DeviceResidentPcgInput<'a> {
    pub storage: &'a DeviceResidentRowHess,
    pub b: &'a [f64],
    pub rel_tol: f64,
    pub max_iters: usize,
    pub precond_diag_floor: f64,
}

Inputs to run_pcg_against_row_hessian_device. The right-hand-side b is supplied as a host slice (it is the only host-resident vector that needs to enter the loop — the iterate, residual, search direction, and Hv output all live on the device).

Fields

storage: &'a DeviceResidentRowHess

Per-fit row-Hessian + design storage. The PCG operator is v ↦ launch_bms_flex_row_hvp_into_device(storage, ...).

b: &'a [f64]

Right-hand-side b, length storage.block.p_total. Uploaded once.

rel_tol: f64

Convergence tolerance on relative residual ‖r‖₂ / ‖b‖₂.

max_iters: usize

Hard cap on iterations (the inner loop also bails on stagnation).

precond_diag_floor: f64

Floor on |diag(H)[i]| used by the Jacobi preconditioner. Set to 1e-12 for the matrix-free row-Hessian path; the row-primary Hessian’s diagonal is positive-definite by construction.