fei1dquad.C

Go to the documentation of this file.

/*
 *
 *                 #####    #####   ######  ######  ###   ###
 *               ##   ##  ##   ##  ##      ##      ## ### ##
 *              ##   ##  ##   ##  ####    ####    ##  #  ##
 *             ##   ##  ##   ##  ##      ##      ##     ##
 *            ##   ##  ##   ##  ##      ##      ##     ##
 *            #####    #####   ##      ######  ##     ##
 *
 *
 *             OOFEM : Object Oriented Finite Element Code
 *
 *               Copyright (C) 1993 - 2025   Borek Patzak
 *
 *
 *
 *       Czech Technical University, Faculty of Civil Engineering,
 *   Department of Structural Mechanics, 166 29 Prague, Czech Republic
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */
 
#include "fei1dquad.h"
#include "mathfem.h"
#include "floatmatrix.h"
#include "floatarray.h"
#include "floatmatrixf.h"
#include "floatarrayf.h"
 
namespace oofem {
 
FloatArrayF<3>
FEI1dQuad :: evalN(double ksi)
{
    return {ksi * ( ksi - 1. ) * 0.5, ksi * ( 1. + ksi ) * 0.5, ( 1. - ksi * ksi )};
}
 
void
FEI1dQuad :: evalN(FloatArray &answer, const FloatArray &lcoords, const FEICellGeometry &cellgeo) const 
{
#if 0
    answer = evalN(lcoords[0]);
#else
    double ksi = lcoords.at(1);
    answer.resize(3);
    answer.zero();
 
    answer.at(1) = ksi * ( ksi - 1. ) * 0.5;
    answer.at(2) = ksi * ( 1. + ksi ) * 0.5;
    answer.at(3) = ( 1. - ksi * ksi );
#endif
}
 
std::pair<double, FloatMatrixF<1,3>>
FEI1dQuad :: evaldNdx(double ksi, const FEICellGeometry &cellgeo) const
{
    double x1 = cellgeo.giveVertexCoordinates(1).at(cindx);
    double x2 = cellgeo.giveVertexCoordinates(2).at(cindx);
    double x3 = cellgeo.giveVertexCoordinates(3).at(cindx);
 
    double J = 1. / 2. * ( 2 * ksi - 1 ) * x1 + 1. / 2. * ( 2 * ksi + 1 ) * x2 - 2. * ksi * x3;
 
    FloatMatrixF<1, 3> ans = {
        ( -1. / 2. + ksi ) / J,
        ( 1. / 2. + ksi ) / J,
        -2. * ksi / J,
    };
    return {J, ans};
}
 
 
double
FEI1dQuad :: evaldNdx(FloatMatrix &answer, const FloatArray &lcoords, const FEICellGeometry &cellgeo) const 
{
    double J = this->giveTransformationJacobian(lcoords, cellgeo);
    double ksi = lcoords.at(1);
    answer.resize(1, 3);
    answer.zero();
 
    answer.at(1, 1) = ( -1. / 2. + ksi ) / J;
    answer.at(1, 2) =  ( 1. / 2. + ksi ) / J;
    answer.at(1, 3) =  -2. * ksi / J;
    return J;
}
 
void
FEI1dQuad :: local2global(FloatArray &answer, const FloatArray &lcoords, const FEICellGeometry &cellgeo) const
{
    FloatArray n;
    answer.resize(1);
 
    this->evalN(n, lcoords, cellgeo);
    answer.at(1) = n.at(1) * cellgeo.giveVertexCoordinates(1).at(cindx) +
                   n.at(2) * cellgeo.giveVertexCoordinates(2).at(cindx) +
                   n.at(3) * cellgeo.giveVertexCoordinates(3).at(cindx);
}
 
int
FEI1dQuad :: global2local(FloatArray &answer, const FloatArray &coords, const FEICellGeometry &cellgeo) const
{
    double x1 = cellgeo.giveVertexCoordinates(1).at(cindx);
    double x2 = cellgeo.giveVertexCoordinates(2).at(cindx);
    double x3 = cellgeo.giveVertexCoordinates(3).at(cindx);
 
    double a = 0.5 * ( x1 + x2 ) - x3;
    double b = 0.5 * ( x2 - x1 );
    double c = x3 - coords.at(1);
 
    answer.resize(1);
    if ( fabs(a) < 1.e-6 ) {
        double ksi = ( 2.0 * coords.at(1) - ( x1 + x2 ) ) / ( x2 - x1 );
        answer.at(1) = clamp(ksi, -1., 1.);
        return fabs(ksi) <= 1.0;
    } else {
        double ksi1 = ( -b + sqrt(b * b - 4. * a * c) ) / ( 2. * a );
        double ksi2 = ( -b - sqrt(b * b - 4. * a * c) ) / ( 2. * a );
 
        if ( ( fabs(ksi1) <= 1. ) && ( fabs(ksi2) <= 1. ) ) { // Two roots, element must be bad
            answer.at(1) = 0.;
            return 0;
        } else if ( fabs(ksi1) <= 1. ) {
            answer.at(1) = ksi1;
            return 1;
        } else if ( fabs(ksi2) <= 1. ) {
            answer.at(1) = ksi2;
            return 1;
        } else {
            answer.at(1) = 0.;
            return 0;
        }
    }
}
 
double
FEI1dQuad :: giveTransformationJacobian(const FloatArray &lcoords, const FEICellGeometry &cellgeo) const 
{
    double x1 = cellgeo.giveVertexCoordinates(1).at(cindx);
    double x2 = cellgeo.giveVertexCoordinates(2).at(cindx);
    double x3 = cellgeo.giveVertexCoordinates(3).at(cindx);
    double ksi = lcoords.at(1);
 
    double J = 1. / 2. * ( 2 * ksi - 1 ) * x1 + 1. / 2. * ( 2 * ksi + 1 ) * x2 - 2. * ksi * x3;
    return J;
}
 
double
FEI1dQuad :: giveLength(const FEICellGeometry &cellgeo) const
{
    return fabs( cellgeo.giveVertexCoordinates(2).at(cindx) - cellgeo.giveVertexCoordinates(1).at(cindx) );
}
 
 
IntArray FEI1dQuad :: boundaryEdgeGiveNodes(int boundary, Element_Geometry_Type egt, bool includeHierarchical) const
{
    return {1, 2, 3};
}
 
void FEI1dQuad :: boundaryEdgeEvalN(FloatArray &answer, int boundary, const FloatArray &lcoords, const FEICellGeometry &cellgeo) const
{
    this->evalN(answer, lcoords, cellgeo);
}
 
double FEI1dQuad :: boundaryEdgeGiveTransformationJacobian(int boundary, const FloatArray &lcoords, const FEICellGeometry &cellgeo) const
{
    return this->giveTransformationJacobian(lcoords, cellgeo);
}
 
void FEI1dQuad :: boundaryEdgeLocal2Global(FloatArray &answer, int boundary, const FloatArray &lcoords, const FEICellGeometry &cellgeo) const
{
    this->local2global(answer, lcoords, cellgeo);
}
 
  
} // end namespace oofem