# elliptic solve

An adaptive multigrid elliptic solver is provided with **HAD**.
The residual necessary for the elliptic solve is specified
in the user defined file "grid_ell.f", which is copied into
"had/src/amr" at compile time. The routine *grid_get_resid*
should be placed in file "grid_ell.f". An example is provided
with **hyperCurvedWave**.

The solver is designed either to be called
periodically throughout an evolution for constrained evolutions
or just to be called once to generate initial data.

Parameters controlling the elliptic solve are:
**elliptic_solve** : if > 0, do an elliptic solve during evolution

: if = 0, no elliptic solves [default]

: if < 0, do an elliptic solve only at initial time
**ell_epsilon** [default: 1.0e-10] threshold residual norm to solve coarse grid
**nvcycle** [default: 1] number of vcycles to execute for solve
**preswp** [default: 3] number of relaxation sweeps pre CGC
**pstswp** [default: 3] number of relaxation sweeps post CGC
**maxsweeps** [default: 1000] maximum number of sweeps on coarse grid to solve

### Notes

A complete example will be forthcoming
### See Also

List of required routines

Index of all manual pages
### Examples

**had/src/hyperCurvedWave/grid_ell.f**