Adapting LinearVariationalProblem causes segfaults when applying BCs

[Former user]

Hi everybody,

I have a code [see #105] in which I have two LinearVariationalProbelms [Pu, Pv] that I solve in a loop, the second of which with an AdaptiveLinearVariationalSolver. What I'm experiencing is this:

• I can solve Pu fine on the initial mesh
• I solve Pv and get the adapted mesh
• I call adapt to adapt Pu
• I solve again Pu but I get a segfault, with this backtrace:

#0  0x00007ffff74dba80 in dolfin::FunctionSpace::dim() const () from /opt/fenics/bld/dolfin/psllep6i5jrg/lib/libdolfin.so.1.6
#1  0x00007ffff7451050 in dolfin::DirichletBC::check_arguments(dolfin::GenericMatrix*, dolfin::GenericVector*, dolfin::GenericVector const*) const ()
   from /opt/fenics/bld/dolfin/psllep6i5jrg/lib/libdolfin.so.1.6
#2  0x00007ffff7456e84 in dolfin::DirichletBC::apply(dolfin::GenericMatrix*, dolfin::GenericVector*, dolfin::GenericVector const*) const ()
   from /opt/fenics/bld/dolfin/psllep6i5jrg/lib/libdolfin.so.1.6

So something is wrong when applying BCs, in particular with the function space on which Pu is defined. I saw a similar bugreport, #322: could this be related?

[Jan Blechta]

This is caused by #319. Workaround is

adapt_wrapper_code = """
#include <dolfin/adaptivity/adapt.h>

namespace dolfin {

std::shared_ptr<MeshFunction<std::size_t>> adapt_wrapper(
  const MeshFunction<std::size_t>& mesh_function,
  std::shared_ptr<const Mesh> adapted_mesh)
{
  std::shared_ptr<MeshFunction<std::size_t>> mf;
  mf = std::make_shared<MeshFunction<std::size_t>>(adapt(mesh_function, adapted_mesh));
  return mf;
}
}
"""

adapt = compile_extension_module(adapt_wrapper_code).adapt_wrapper;

EDIT: This workaround is incorrect. Correct one is to never use returned value of any adapt function, see #319.

[Jan Blechta]

Duplicate of #319.

[Martin Sandve Alnæs]

Removing milestone: 1.6 (automated comment)