This is a PETSc option that usually causes trouble, especially when a
user already has MPI installed on their machine.
<p>
This automatically builds PETSc with both MPI and the algebraic
- multigrid preconditioner package Hypre (which we use in step-40).
+ multigrid preconditioner package Hypre (which we use in step-40). If you
+ would like to use PETSc with MPI then we recommend that you install MPI
+ through your package manager instead of letting PETSc install it: put
+ another way, installing PETSc with the flag <code>--download-mpich</code>
+ often causes problems (such as linking errors or poor performance)
+ that may be avoided by using whatever your system provides instead.
<br>
Now let PETSc check his own sanity:
<pre>
In the beginning the Universe was created. This has made a lot of
people very angry and has been widely regarded as a bad move.
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