linDG2D/elementPair.hh

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// element pair for linear DG FEM in 2D

#ifndef elementPairDG2D_hh
#define elementPairDG2D_hh

#include "space/elementPairs.hh"
#include "edgeInfo.hh"

// debugging
#include "basics/debug.hh"

#define DGElementPair2dConstr_D 0

namespace linDG2D {

  using concepts::Real;

  // *********************************************************** ElementPair **

  class ElementPair : public concepts::ElementPair<Real> {
  public:
    ElementPair(const Triangle& elm1, const Triangle& elm2, 
                const EdgeInfo& edgeInfo) : 
      elm1_(elm1), elm2_(elm2), edgeInfo_(edgeInfo) {
      DEBUGL(DGElementPair2dConstr_D, elm1 << ", " << elm2);
      idxs_[0] = &(elm1.cell()) == edgeInfo.cell(0) ? 
        edgeInfo.idx(0) : edgeInfo.idx(1);
      idxs_[1] = &(elm2.cell()) == edgeInfo.cell(0) ? 
        edgeInfo.idx(0) : edgeInfo.idx(1);
    }
    virtual const Triangle& elm1() const { return elm1_; }
    virtual const Triangle& elm2() const { return elm2_; }
    const EdgeInfo& edgeInfo() const { return edgeInfo_; }
    Real shapeFct(uint e, uint i, Real xi) const {
      const Triangle& elm = e == 0 ? elm1_ : elm2_;
      Real xim = &(elm.cell()) == edgeInfo_.cell(0) ? xi : 1.0 - xi;
      switch(idxs_[e]) {
      case 0: return elm.shapeFct(i, xim, 0.0);
      case 1: return elm.shapeFct(i, 1.0, xim);
      case 2: return elm.shapeFct(i, 1.0-xim, 1.0-xim);
      default: conceptsAssert(false, concepts::Assertion()); return 0.0;
      }
    }
  private:
    const Triangle& elm1_;
    const Triangle& elm2_;
    const EdgeInfo& edgeInfo_;
    uint idxs_[2];
  };

}

#endif // elementPairDG2D_hh