# Eigenvalue solver¶

By using the SLEPc library, BOUT++ can be used as an eigenvalue solver to find the eigenvectors and eigenvalues of sets of equations.

## Configuring with SLEPc¶

The BOUT++ interface has been tested with SLEPc version 3.4.3, itself compiled with PETSc 3.4.2. SLEPc version 3.4 should work, but other versions will not yet.

## SLEPc options¶

Time derivatives can be taken directly from the RHS function, or by advancing the simulation in time by a relatively large increment. This second method acts to damp high frequency components

## Examples¶

### Wave in a box¶

examples/eigen-box