MatNestSetVecType in petsc4py

[Miguel Salazar]

It would be nice if we had this functionality in petsc4py. Now when using a MatNest, the associated vector cannot be VecNest, which difficults its assembly given that it is necessary to assemble a different vector created from the matrix which is MatNest

A = PETSc.Mat()
A.create(PETSc.COMM_WORLD)
A.createNest([[a_11, a_12], [a_21, None]]) # assume a_11, a_12 and a_21 are regular PETSc matrices
x, b = A.createVecs()

and now we have to assemble b from the different vectors, when we could create a VecNest directly and use it with A.

[Lisandro Dalcin]

Any chance you could contribute a pull request to be merged in branch maint?

[Miguel Salazar]

I ended up using a different strategy and I no longer need this feature.

[Miguel Salazar]

No longer needed.