BF_C_Q_Q1_2D.h

// ***********************************************************************
// Q1 element, conforming, 2D
// ***********************************************************************

// base function values
static void C_Q_Q1_2D_Funct(double xi, double eta, double *values)
{
  values[0]=0.25*(1-xi-eta+xi*eta);
  values[1]=0.25*(1+xi-eta-xi*eta);
  values[2]=0.25*(1-xi+eta-xi*eta);
  values[3]=0.25*(1+xi+eta+xi*eta);
}

// values of the derivatives in xi direction
static void C_Q_Q1_2D_DeriveXi(double xi, double eta, double *values)
{
  values[0]=0.25*(-1+eta);
  values[1]=0.25*( 1-eta);
  values[2]=0.25*(-1-eta);
  values[3]=0.25*( 1+eta);
}

// values of the derivatives in eta direction
static void C_Q_Q1_2D_DeriveEta(double xi, double eta, double *values)
{
  values[0]=0.25*(-1+xi);
  values[1]=0.25*(-1-xi);
  values[2]=0.25*( 1-xi);
  values[3]=0.25*( 1+xi);
}
// values of the derivatives in xi-xi  direction
static void C_Q_Q1_2D_DeriveXiXi(double xi, double eta, double *values)
{
  values[0]=0;
  values[1]=0;
  values[2]=0;
  values[3]=0;
}
// values of the derivatives in xi-eta direction
static void C_Q_Q1_2D_DeriveXiEta(double xi, double eta, double *values)
{
  values[0]=0.25;
  values[1]=-0.25;
  values[2]=-0.25; 
  values[3]=0.25;
}
// values of the derivatives in eta-eta direction
static void C_Q_Q1_2D_DeriveEtaEta(double xi, double eta, double *values)
{
  values[0]=0;
  values[1]=0;
  values[2]=0;
  values[3]=0;  
}


// ***********************************************************************

TBaseFunct2D *BF_C_Q_Q1_2D_Obj = new TBaseFunct2D
        (4, BF_C_Q_Q1_2D, BFUnitSquare, 
         C_Q_Q1_2D_Funct, C_Q_Q1_2D_DeriveXi,
         C_Q_Q1_2D_DeriveEta, C_Q_Q1_2D_DeriveXiXi,
         C_Q_Q1_2D_DeriveXiEta, C_Q_Q1_2D_DeriveEtaEta, 1, 1,
         0, NULL);