This patch adds methods for `Base.unsafe_convert` for `HYPREMatrix`,
`HYPREVector`, and `HYPRESolver`. This means that those objects can be
passed directly to `ccall` and be "converted" (i.e. extracting the
pointer that is stored in the structs) to the appropriate type expected
by the HYPRE C-library. The advantage is that `ccall` then guarantees
that the objects are kept alive for the duration of the call.
Some solvers have option from the specific ParCSR solver + options for
the general solver. This updates the option generator to handle this
such that the specific method is preferred over the generic one. This
patch also include the result of the generator applied to PCG, which has
some specific options for ParCSRPCG.
Settings are passed as keyword arguments, just like BoomerAMG. The
Precond argument (corresponding to PCGSetPrecond) is handled separately,
and lets you pass another solver directly, instead of the solver
pointer, the setup and solve functions, as in the SetPrecond C function.
Example:
precond = BoomerAMG(; options...)
solver = PCG(; Precond = precond, options...)
This commits contains the solver interface:
A = HYPREMatrix(...)
b = HYPREVector(...)
x = HYPREVector(...)
solver = HYPRESolver(; options...)
solve!(solver, x, A, b)
where the abstract type HYPRESolver is replaced by a concrete solver
implementation (this commit includes the concrete
implementation/wrapping of BoomerAMG <: HYPRESolver).
Solver settings are passed as keyword arguments to the solver
constructor, cf. SetXXX functions in HYPRE.
For example, to create a BoomerAMG solver, and setting the tolerance:
solver = BoomerAMG(Tol = 1e-7)
Keyword argument names correspond directly to the solvers SetXXX
function in HYPRE; passing Tol corresponds to
HYPRE_BoomerAMGSetTol(solver, 1e-7).
Fredrik Ekre