def Solve(a, f, petsc_opts, kvecs):
ngs.ngsglobals.msg_level = 5
gfu = ngs.GridFunction(a.space)
with ngs.TaskManager():
a.Assemble()
f.Assemble()
ngs.ngsglobals.msg_level = 5
awrap = petsc.PETScMatrix(a.mat,
V.FreeDofs(),
format=petsc.PETScMatrix.AIJ)
awrap.SetNearNullSpace(kvecs)
c = petsc.KSP(awrap,
finalize=True,
name="msaKSP",
petsc_options=petsc_opts)
gfu.vec.data = c * f.vec
return gfu
def Solve(a, f, petsc_opts, kvecs):
ngs.ngsglobals.msg_level = 5
gfu = ngs.GridFunction(a.space)
with ngs.TaskManager():
a.Assemble()
f.Assemble()
ngs.ngsglobals.msg_level = 5
awrap = petsc.PETScMatrix(a.mat, V.FreeDofs(), format=petsc.PETScMatrix.AIJ)
awrap.SetNearNullSpace(kvecs)
c = petsc.KSP(awrap, finalize=True, name="msaKSP", petsc_options = petsc_opts)
ngs.mpi_world.Barrier()
ts = ngs.mpi_world.WTime()
gfu.vec.data = c * f.vec
ngs.mpi_world.Barrier()
ts = ngs.mpi_world.WTime() - ts
print("ndof ", a.space.ndofglobal)
print("dofs / (sec * np) = ", (a.space.ndofglobal * a.space.dim) / (ts * max(ngs.mpi_world.size-1,1)))
return gfu
ucf = CoefficientFunction((RBM[0], RBM[1]))
upart.Set(ucf)
v = gfu.vec.CreateVector()
v.data = gfu.vec
rbm_vecs.append(v)
return rbm_vecs
petsc.Initialize()
mat_wrap = petsc.PETScMatrix(a.mat,
freedofs=V.FreeDofs(),
format=petsc.PETScMatrix.AIJ)
opts = {"ksp_type": "cg", "ksp_atol": 1e-30, "ksp_rtol": 1e-8, "pc_type": "ml"}
ksp = petsc.KSP(mat=mat_wrap,
name="someksp",
petsc_options=opts,
finalize=False)
ksp.GetMatrix().SetNearNullSpace(rb_modes(V))
# import ngs_amg
# mat_wrap = petsc.FlatPETScMatrix(a.mat, freedofs=V.FreeDofs())
# ngs_amg_opts = {"energy" : "alg", "comp_sm" : True, "force_comp_sm" : True, "max_cv" : 500, "ass_frac" : 0.15, "skip_ass" : 3}
# ngs_pc = ngs_amg.AMG_EL2(blf=a, freedofs=V.FreeDofs(), **ngs_amg_opts)
# ngs_pc = petsc.NGs2PETSc_PC(mat=mat_wrap, pc=ngs_pc)
# ksp.SetPC(ngs_pc)
ksp.Finalize()
from time import time
t = -time()
gfu.vec.data = ksp * f.vec
import ngs_petsc as petsc
petsc.Initialize()
opts = {
"ksp_type": "gmres",
"ksp_atol": 1e-30,
"ksp_rtol": 1e-14,
"ksp_max_its": 1e6,
"ksp_monitor": "",
"ksp_converged_reason": "",
#"ksp_view" : "",
"pc_type": "none"
}
# pmat = petsc.FlatPETScMatrix(a.mat, X.FreeDofs())
pmat = petsc.PETScMatrix(a.mat, X.FreeDofs())
inv_stokes = petsc.KSP(mat=pmat,
name="ngs",
petsc_options=opts,
finalize=False)
fs_opts = {"pc_fieldsplit_detect_saddle_point": ""}
# fs_opts = {"pc_fieldsplit_detect_saddle_point" : "", "fieldsplit_1_pc_type" : "jacobi"}
# fs_opts = {"pc_fieldsplit_schur_fact_type" : "full", "fieldsplit_pfield_pc_type" : "bjacobi"}
# fs_opts = dict()
fs_opts = {
"pc_fieldsplit_type": "schur",
"pc_fieldsplit_schur_fact_type": "diag",
# "pc_fieldsplit_detect_saddle_point" : "",
"pc_fieldsplit_schur_precondition": "selfp",
"fieldsplit_0_pc_type": "jacobi",
# "fieldsplit_0_ksp_monitor" : "",
#"fieldsplit_0_ksp_converged_reason" : "",
"fieldsplit_1_pc_type": "jacobi",
ngp.Initialize()
wrapped_mat = ngp.PETScMatrix(a.mat,
freedofs=V.FreeDofs(),
format=ngp.PETScMatrix.IS_AIJ)
# gives access to the petsc4py mat
p4p_mat = wrapped_mat.GetPETScMat()
if comm.size > 1:
p4p_mat.convert("mpiaij")
# this is a wrapper around a KSP
wrapped_ksp = ngp.KSP(mat=wrapped_mat,
name="someksp",
petsc_options={
"ksp_type": "cg",
"pc_type": "gamg"
},
finalize=False)
# this is the petsc4py KSP
ksp = wrapped_ksp.GetKSP()
ksp.setTolerances(1e-6, 0, 1e12, 20)
ksp.setMonitor(lambda a, b, c: print("it", b, "err", c))
wrapped_ksp.Finalize()
# can map between NGSolve and PETSc vectors
vec_map = wrapped_mat.GetRowMap()
psc_rhs = vec_map.CreatePETScVector()
psc_sol = vec_map.CreatePETScVector()