fei1dquad.C

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/*
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 *
 *
 *             OOFEM : Object Oriented Finite Element Code
 *
 *               Copyright (C) 1993 - 2013   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"

namespace oofem {
void
FEI1dQuad :: evalN(FloatArray &answer, const FloatArray &lcoords, const FEICellGeometry &cellgeo)
{
    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 );
}

double
FEI1dQuad :: evaldNdx(FloatMatrix &answer, const FloatArray &lcoords, const FEICellGeometry &cellgeo)
{
    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)
{
    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)
{
    double x1, x2, x3;
    double a, b, c;

    x1 = cellgeo.giveVertexCoordinates(1)->at(cindx);
    x2 = cellgeo.giveVertexCoordinates(2)->at(cindx);
    x3 = cellgeo.giveVertexCoordinates(3)->at(cindx);

    a = 0.5 * ( x1 + x2 ) - x3;
    b = 0.5 * ( x2 - x1 );
    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)
{
    double x1, x2, x3, J, ksi;

    x1 = cellgeo.giveVertexCoordinates(1)->at(cindx);
    x2 = cellgeo.giveVertexCoordinates(2)->at(cindx);
    x3 = cellgeo.giveVertexCoordinates(3)->at(cindx);
    ksi = lcoords.at(1);

    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) );
}


void FEI1dQuad :: boundaryEdgeGiveNodes(IntArray &answer, int boundary)
{
  answer={1, 2, 3};
}

void FEI1dQuad :: boundaryEdgeEvalN(FloatArray &answer, int boundary, const FloatArray &lcoords, const FEICellGeometry &cellgeo)
{
  this->evalN(answer, lcoords, cellgeo);
}

double FEI1dQuad :: boundaryEdgeGiveTransformationJacobian(int boundary, const FloatArray &lcoords, const FEICellGeometry &cellgeo)
{
    return this->giveTransformationJacobian(lcoords, cellgeo);
}

void FEI1dQuad :: boundaryEdgeLocal2Global(FloatArray &answer, int boundary, const FloatArray &lcoords, const FEICellGeometry &cellgeo)
{
    this->local2global(answer, lcoords, cellgeo);
}

  
} // end namespace oofem