SquareI.H

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#include "Square.H"
#include "mathematicalConstants.H"

// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //

template<class Type>
inline Type Foam::Function1s::Square<Type>::value(const scalar x) const
{
    const scalar markFraction = markSpace_/(1 + markSpace_);

    const scalar phi = frequency_*(x - start_);
    const scalar fraction = phi - floor(phi);

    return
        amplitude_->value(x)*(fraction < markFraction ? 1 : -1)
      + level_->value(x);
}


template<class Type>
inline Type Foam::Function1s::Square<Type>::integral
(
    const scalar x1,
    const scalar x2
) const
{
    if (!integrable_)
    {
        FatalErrorInFunction
            << "Integration is not defined for " << type() << " functions "
            << "unless the amplitude is constant"
            << exit(FatalError);
    }

    auto integral0 = [&](const scalar x)
    {
        const scalar markFraction = markSpace_/(1 + markSpace_);

        const scalar phi = frequency_*(x - start_);
        const scalar fraction = phi - floor(phi);

        return
            (2*amplitude_->value(x)/frequency_)
           *(
               markFraction*floor(phi + 1 - markFraction)
             + fraction*(fraction < markFraction ? 1 : 0)
             - frequency_/2*x
            );
    };

    return integral0(x2) - integral0(x1) + level_->integral(x1, x2);
}


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