Memory use will depend on the preconditioner. This will converge very
slowly (i.e., never) without multigrid unless time steps are small.
Depending on how rough the coefficients are, you may be able to use
geometric multigrid, which has pretty low setup costs and memory
requirements.
To estimate
Hi,
I've solving a simple linear equation [ u_t = A*u_xx + A*u_yy + F_t*u ] on
a grid size of 55296x55296. I'm reading a vector of that size from an hdf5
file and have the jacobian matrix as a modified 5-point stencil which is
preallocated with the following
```
ierr =
