def test_solving(self): from sfepy.base.base import IndexedStruct from sfepy.fem \ import FieldVariable, Material, ProblemDefinition, \ Function, Equation, Equations, Integral from sfepy.fem.conditions import Conditions, EssentialBC from sfepy.terms import Term from sfepy.solvers.ls import ScipyDirect from sfepy.solvers.nls import Newton u = FieldVariable('u', 'unknown', self.field, self.dim) v = FieldVariable('v', 'test', self.field, self.dim, primary_var_name='u') m = Material('m', lam=1.0, mu=1.0) f = Material('f', val=[[0.02], [0.01]]) bc_fun = Function('fix_u_fun', fix_u_fun, extra_args={'extra_arg' : 'hello'}) fix_u = EssentialBC('fix_u', self.gamma1, {'u.all' : bc_fun}) shift_u = EssentialBC('shift_u', self.gamma2, {'u.0' : 0.1}) integral = Integral('i', order=3) t1 = Term.new('dw_lin_elastic_iso(m.lam, m.mu, v, u)', integral, self.omega, m=m, v=v, u=u) t2 = Term.new('dw_volume_lvf(f.val, v)', integral, self.omega, f=f, v=v) eq = Equation('balance', t1 + t2) eqs = Equations([eq]) ls = ScipyDirect({}) nls_status = IndexedStruct() nls = Newton({}, lin_solver=ls, status=nls_status) pb = ProblemDefinition('elasticity', equations=eqs, nls=nls, ls=ls) ## pb.save_regions_as_groups('regions') pb.time_update(ebcs=Conditions([fix_u, shift_u])) state = pb.solve() name = op.join(self.options.out_dir, 'test_high_level_solving.vtk') pb.save_state(name, state) ok = nls_status.condition == 0 if not ok: self.report('solver did not converge!') _ok = state.has_ebc() if not _ok: self.report('EBCs violated!') ok = ok and _ok return ok
def set_solvers_instances(self, ls=None, nls=None): """ Set the instances of linear and nonlinear solvers that will be used in `Problem.solve()` call. """ if (ls is not None) and (nls is not None): if not (nls.lin_solver is ls): raise ValueError('linear solver not used in nonlinear!') self.solvers = Struct(name='solvers', ls=ls, nls=nls) if nls is not None: self.nls_status = get_default(nls.status, IndexedStruct())
def solve_step(self, ts, nls, vec, prestep_fun): """ Solve a single time step. """ status = IndexedStruct(n_iter=0, condition=0) while 1: vect = nls(vec, status=status) is_break = self.adapt_time_step(ts, status, self.adt, self.context, verbose=self.verbose) if is_break: break prestep_fun(ts, vec) return vect
def test_input(self): import numpy as nm from sfepy.applications import solve_pde self.report('solving %s...' % self.conf.input_name) status = IndexedStruct(nls_status=NLSStatus(conditions=[])) solve_pde(self.test_conf, self.solver_options, status=status, output_dir=self.options.out_dir, step_hook=self.step_hook, post_process_hook=self.post_process_hook, post_process_hook_final=self.post_process_hook_final) self.report('%s solved' % self.conf.input_name) ok = self.check_conditions(nm.array(status.nls_status.conditions)) return ok
def main(argv=None): options = parse_args(argv=argv) # vvvvvvvvvvvvvvvv # approx_order = 2 # ^^^^^^^^^^^^^^^^ # # Setup output names outputs_folder = options.output_dir domain_name = "domain_1D" problem_name = "iburgers_1D" output_folder = pjoin(outputs_folder, problem_name, str(approx_order)) output_format = "vtk" save_timestn = 100 clear_folder(pjoin(output_folder, "*." + output_format)) configure_output({ 'output_screen': True, 'output_log_name': pjoin(output_folder, f"last_run_{problem_name}_{approx_order}.txt") }) # ------------ # | Get mesh | # ------------ X1 = 0. XN = 1. n_nod = 100 n_el = n_nod - 1 mesh = get_gen_1D_mesh_hook(X1, XN, n_nod).read(None) # ----------------------------- # | Create problem components | # ----------------------------- integral = Integral('i', order=approx_order * 2) domain = FEDomain(domain_name, mesh) omega = domain.create_region('Omega', 'all') left = domain.create_region('Gamma1', 'vertices in x == %.10f' % X1, 'vertex') right = domain.create_region('Gamma2', 'vertices in x == %.10f' % XN, 'vertex') field = DGField('dgfu', nm.float64, 'scalar', omega, approx_order=approx_order) u = FieldVariable('u', 'unknown', field, history=1) v = FieldVariable('v', 'test', field, primary_var_name='u') MassT = Term.new('dw_dot(v, u)', integral, omega, u=u, v=v) velo = nm.array(1.0) def adv_fun(u): vu = velo.T * u[..., None] return vu def adv_fun_d(u): v1 = velo.T * nm.ones(u.shape + (1, )) return v1 burg_velo = velo.T / nm.linalg.norm(velo) def burg_fun(u): vu = burg_velo * u[..., None]**2 return vu def burg_fun_d(u): v1 = 2 * burg_velo * u[..., None] return v1 StiffT = Term.new('dw_ns_dot_grad_s(fun, fun_d, u[-1], v)', integral, omega, u=u, v=v, fun=burg_fun, fun_d=burg_fun_d) # alpha = Material('alpha', val=[.0]) # FluxT = AdvectDGFluxTerm("adv_lf_flux(a.val, v, u)", "a.val, v, u[-1]", # integral, omega, u=u, v=v, a=a, alpha=alpha) FluxT = Term.new('dw_dg_nonlinear_laxfrie_flux(fun, fun_d, v, u[-1])', integral, omega, u=u, v=v, fun=burg_fun, fun_d=burg_fun_d) eq = Equation('balance', MassT - StiffT + FluxT) eqs = Equations([eq]) # ------------------------------ # | Create boundary conditions | # ------------------------------ left_fix_u = EssentialBC('left_fix_u', left, {'u.all': 1.0}) right_fix_u = EssentialBC('right_fix_u', right, {'u.all': 0.0}) # ---------------------------- # | Create initial condition | # ---------------------------- def ghump(x): """ Nice gaussian. """ return nm.exp(-200 * x**2) def ic_wrap(x, ic=None): return ghump(x - .3) ic_fun = Function('ic_fun', ic_wrap) ics = InitialCondition('ic', omega, {'u.0': ic_fun}) # ------------------ # | Create problem | # ------------------ pb = Problem(problem_name, equations=eqs, conf=Struct(options={"save_times": save_timestn}, ics={}, ebcs={}, epbcs={}, lcbcs={}, materials={}), active_only=False) pb.setup_output(output_dir=output_folder, output_format=output_format) pb.set_ics(Conditions([ics])) # ------------------ # | Create limiter | # ------------------ limiter = MomentLimiter1D # --------------------------- # | Set time discretization | # --------------------------- CFL = .2 max_velo = nm.max(nm.abs(velo)) t0 = 0 t1 = .2 dx = nm.min(mesh.cmesh.get_volumes(1)) dt = dx / max_velo * CFL / (2 * approx_order + 1) tn = int(nm.ceil((t1 - t0) / dt)) dtdx = dt / dx # ------------------ # | Create solver | # ------------------ ls = ScipyDirect({}) nls_status = IndexedStruct() nls = Newton({'is_linear': True}, lin_solver=ls, status=nls_status) tss_conf = { 't0': t0, 't1': t1, 'n_step': tn, 'limiters': { "dgfu": limiter } } tss = TVDRK3StepSolver(tss_conf, nls=nls, context=pb, verbose=True) # --------- # | Solve | # --------- pb.set_solver(tss) state_end = pb.solve() output("Solved equation \n\n\t\t u_t - div(f(u))) = 0\n") output(f"With IC: {ic_fun.name}") # output("and EBCs: {}".format(pb.ebcs.names)) # output("and EPBCS: {}".format(pb.epbcs.names)) output("-------------------------------------") output(f"Approximation order is {approx_order}") output(f"Space divided into {mesh.n_el} cells, " + f"{len(mesh.coors)} steps, step size is {dx}") output(f"Time divided into {tn - 1} nodes, {tn} steps, step size is {dt}") output(f"CFL coefficient was {CFL} and " + f"order correction {1 / (2 * approx_order + 1)}") output(f"Courant number c = max(abs(u)) * dt/dx = {max_velo * dtdx}") output("------------------------------------------") output(f"Time stepping solver is {tss.name}") output(f"Limiter used: {limiter.name}") output("======================================") # ---------- # | Plot 1D| # ---------- if options.plot: load_and_plot_fun(output_folder, domain_name, t0, t1, min(tn, save_timestn), ic_fun)