marker are not preserved by operatorLagrangeP1

[Doyeux]

When creating a P1 mesh with operatorLagrangeP1, the markers are not transmitted to the P1 mesh.
Could it be done ? The elements coming from a marked element could have the same marker (at least for marker1).

[vincentchabannes]

It's strange, I looked quickly the code and normally it's done.

[Doyeux]

The following code reproduces the problem

#include <feel/feelfilters/exporter.hpp>
#include <feel/feeldiscr/pch.hpp>
#include <feel/feelfilters/unithypercube.hpp>
#include <feel/feeldiscr/operatorinterpolation.hpp>
#include <feel/feeldiscr/operatorlagrangep1.hpp>

using namespace Feel;
using namespace Feel::vf;

int main( int argc, char** argv )
{

  const int dim = 2;
  const int order = 2;

  Feel::Environment env( argc, argv );

  // mesh and high order space
  auto mesh = unitHypercube<dim>();
  auto Xh = Pch<order>(mesh);

  // operator lagrange P1 and associated space
  auto opLagP1 = lagrangeP1( Xh );
  auto XhP1 = Pch<1>( opLagP1->mesh() );

  // interpolation operator
  auto opIntHoToP1 = opInterpolation(_domainSpace = Xh, _imageSpace = XhP1, _type=InterpolationNonConforme(false) );
  auto opIntP1ToHo = opInterpolation(_domainSpace = XhP1, _imageSpace = Xh, _type=InterpolationNonConforme(false) );

  auto markerOrderN = Xh->element();
  auto markerP1 = XhP1->element();

  for (int i=1; i<5; ++i)
      {
          markerOrderN += vf::project(Xh, markedfaces(mesh, i),
                                      cst(i) );

          markerP1+= vf::project(XhP1, markedfaces(opLagP1->mesh(), i),
                                 cst(i) );

          double a = integrate( markedfaces(mesh, i), cst(1.) ).evaluate()(0,0);
          double b = integrate( markedfaces(opLagP1->mesh(), i), cst(1.) ).evaluate()(0,0);

          LOG(INFO)<< "integrate on the face number " << i << "\n"
                   << "on Pn mesh " << a << "\n"
                   << "on P1 mesh " << b << "\n";
      }

  auto expP1 = exporter(_mesh=opLagP1->mesh(), _name="markerP1_exp");
  expP1->step(0)->add("markerP1", markerP1);
  expP1->save();

  auto expPN = exporter(_mesh=mesh, _name="markerPN_exp");
  expPN->step(0)->add("markerOrderN", markerOrderN);
  expPN->save();

  return 0;
} 

[vincentchabannes]

Ah, it's for the faces, not elements. I didn't well understand.
I will try to fix that.

[vincentchabannes]

@Doyeux Now, it's work for me. You can close the issue if it's also OK for you

[Doyeux]

Ok, sounds good. I close the issue!