[petsc-users] -ksp_diagonal_scale question

[Max Rudolph]

I was looking at the documentation for KSPSetDiagonalScale and it
contains this comment:

"This routine is only used if the matrix and preconditioner matrix are
the same thing."

However, I have found that even if the matrix and preconditioner are
different, using the -ksp_diagonal_scale command line argument changes
the convergence behavior of the solvers. Is the man page correct?
Also, can you point me towards documentation of the type of scaling
that is applied?

Thanks for your help,
Max Rudolph