for_one.cpp

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First Order Partial Driver: Example and Test

# include <cppad/cppad.hpp>
namespace { // -------------------------------------------------------
// define the template function ForOneCases<Vector> in empty namespace
template <class Vector>
bool ForOneCases()
{   bool ok = true;
    using CppAD::AD;
    using CppAD::NearEqual;
    double eps99 = 99.0 * std::numeric_limits<double>::epsilon();
    using CppAD::exp;
    using CppAD::sin;
    using CppAD::cos;

    // domain space vector
    size_t n = 2;
    CPPAD_TESTVECTOR(AD<double>)  X(n);
    X[0] = 1.;
    X[1] = 2.;

    // declare independent variables and starting recording
    CppAD::Independent(X);

    // range space vector
    size_t m = 3;
    CPPAD_TESTVECTOR(AD<double>)  Y(m);
    Y[0] = X[0] * exp( X[1] );
    Y[1] = X[0] * sin( X[1] );
    Y[2] = X[0] * cos( X[1] );

    // create f: X -> Y and stop tape recording
    CppAD::ADFun<double> f(X, Y);

    // new value for the independent variable vector
    Vector x(n);
    x[0] = 2.;
    x[1] = 1.;

    // compute partial of y w.r.t x[0]
    Vector dy(m);
    dy  = f.ForOne(x, 0);
    ok &= NearEqual( dy[0], exp(x[1]), eps99, eps99); // for y[0]
    ok &= NearEqual( dy[1], sin(x[1]), eps99, eps99); // for y[1]
    ok &= NearEqual( dy[2], cos(x[1]), eps99, eps99); // for y[2]

    // compute partial of F w.r.t x[1]
    dy  = f.ForOne(x, 1);
    ok &= NearEqual( dy[0],  x[0]*exp(x[1]), eps99, eps99);
    ok &= NearEqual( dy[1],  x[0]*cos(x[1]), eps99, eps99);
    ok &= NearEqual( dy[2], -x[0]*sin(x[1]), eps99, eps99);

    return ok;
}
} // End empty namespace
# include <vector>
# include <valarray>
bool ForOne(void)
{   bool ok = true;
    // Run with Vector equal to three different cases
    // all of which are Simple Vectors with elements of type double.
    ok &= ForOneCases< CppAD::vector  <double> >();
    ok &= ForOneCases< std::vector    <double> >();
    ok &= ForOneCases< std::valarray  <double> >();
    return ok;
}