Bug in AMGPreconditioner

[pmartorell]

Hi,

since AlgebraicMultigrid v0.4.1 the code breaks in the following snipped:

using IterativeSolvers
using Preconditioners
using AlgebraicMultigrid

A = poisson(1000)
b = A*ones(1000)
p = AMGPreconditioner{SmoothedAggregation}(A)
cg(A,b,Pl=p)

However, the raw preconditioner can still be used from AlgebraicMultigrid package:

p = aspreconditioner(smoothed_aggregation(A))

[mohamed82008]

Thanks for the report. I opened a PR to fix this.