/*
 Copyright (C) 2008 Srinivas Hasti

 This source code is release under the BSD License.

 This file is part of JQuantLib, a free-software/open-source library
 for financial quantitative analysts and developers - http://jquantlib.org/

 JQuantLib is free software: you can redistribute it and/or modify it
 under the terms of the JQuantLib license.  You should have received a
 copy of the license along with this program; if not, please email
 . The license is also available online at
 .

 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 license for more details.

 JQuantLib is based on QuantLib. http://quantlib.org/
 When applicable, the original copyright notice follows this notice.
 */

/*
 Copyright (C) 2000, 2001, 2002, 2003 RiskMap srl

 This file is part of QuantLib, a free-software/open-source library
 for financial quantitative analysts and developers - http://quantlib.org/

 QuantLib is free software: you can redistribute it and/or modify it
 under the terms of the QuantLib license.  You should have received a
 copy of the license along with this program; if not, please email
 . The license is also available online at
 .

 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 license for more details.
*/

package org.jquantlib.methods.finitedifferences;

import org.jquantlib.math.matrixutilities.Array;

/**
 * Neumann boundary condition (i.e., constant value)
 *
 * @category findiff
 *
 * @author Srinivas Hasti
 */
public class DirichletBC implements BoundaryCondition {

    private final /* @Real */double value;
    private final Side side;

    public DirichletBC(final double value, final Side side) {
        this.value = value;
        this.side = side;
    }

    @Override
    public void applyAfterApplying(final Array u) {
        switch (side) {
        case Lower:
            u.set(0, value);
            break;
        case Upper:
            u.set(u.size() - 1, value);
            break;
        default:
            throw new IllegalStateException("unknown side for Neumann boundary condition");
        }
    }

    @Override
    public void applyAfterSolving(final Array array) {

    }

    @Override
    public void applyBeforeApplying(final TridiagonalOperator operator) {
        switch (side) {
        case Lower:
            operator.setFirstRow(1.0, 0.0);
            break;
        case Upper:
            operator.setLastRow(0.0, 1.0);
            break;
        default:
            throw new IllegalStateException("unknown side for Neumann boundary condition");
        }
    }

    @Override
    public void applyBeforeSolving(final TridiagonalOperator operator, final Array rhs) {
        switch (side) {
        case Lower:
            operator.setFirstRow(1.0, 0.0);
            rhs.set(0, value);
            break;
        case Upper:
            operator.setLastRow(0.0, 1.0);
            rhs.set(rhs.size() - 1, value);
            break;
        default:
            throw new IllegalStateException("unknown side for Neumann boundary condition");
        }
    }

    @Override
    public void setTime(final double t) {
    }
}