<a name="Customized Multigrid Preconditioner"></a>
<h1>This example shows how to customize the multigrid preconditioner.</h1>

<h3> In this example, we first read in a matrix from a file. The preconditioned CG solver is enhanced
with a multigrid preconditioner. Several non-default options are used to create this preconditioner.
The example features the generating time and runtime of the CG solver.</h3>

