Number of V-cycle iterations to perform. The solution will be more accurate with a higher number of iterations, but will also take longer to produce.

The method used for relaxation on up- and down-strokes. Gauss-Seidel offers better asymptotic convergence; it also requires less memory, as the red-black partitioning of cells allows for in-place smoothing. The Jacobi method, on the other hand, works on all pixels at once. This avoids systemic checkerboard patterns in the residuals, but requires an extra copy of the image.

Number of smoothing iterations to perform on the up-stroke (after prolongation of the coarse solution). Higher values will increase cost, but also improve the solution.

Number of smoothing iterations to perform on the down-stroke (before restriction of the fine residual). Higher values will increase cost, but also improve the solution.

Number of smoothing iterations to perform at the final coarsest level (in lieu of an exact solution). Higher values will increase cost, but also improve the solution. Value of this parameter should be on the same order as square of Target Coarse Dimensions.

The multigrid solver iteratively coarsens the layer to build a hierarchy of grids for rapid convergence at all scales. This parameter controls when the coarsening ceases; namely, coarsening along a dimension will stop once the number of cells falls below Target Coarse Dimensions. While larger values give a leaner hierarchy with fewer levels, they also result in larger number of variables at the coarsest level, which in turn may require more Coarsest Smoothing Iterations for adequate convergence.

State of borders on the left and right sides of the layer. Open borders correspond to Dirichlet boundary conditions (prescribing value of 0). Closed borders correspond to Neumann boundary conditions (enforcing normal derivative of 0). When set to Periodic, left and right sides of the layer are virtually connected.

State of borders on the bottom and top sides of the image. Open borders correspond to Dirichlet boundary conditions (prescribing value of 0). Closed borders correspond to Neumann boundary conditions (enforcing normal derivative of 0). When set to Periodic, bottom and top sides of the layer are virtually connected.