[petsc-users] how to compute a projection space

[Alp Kalpalp]

Hi,

I need to compute the following in petsc;

P = I -(Z * inv(Z'*A*Z) * Z'

What is the best way to compute this?

I am planing to use MatPtAP in order to compute the expression inside of
the inverse. And then use
MatMatSolve instead of inv and comtinue with MatMatMult and use MatShift
finally.

Any suggestions or comments are welcome..