AD Absolute Zero Multiplication: Example and Test
Keywords: ad absolute zero multiplication: example test

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AD Absolute Zero Multiplication: Example and Test
`

    # include <cppad/cppad.hpp>
    # include <cmath>

    bool azmul(void)
    {	bool ok = true;

    	using CppAD::AD;
    	using CppAD::NearEqual;
    	double inf = std::numeric_limits<double>::infinity();
    	double eps = 10. * std::numeric_limits<double>::epsilon();

    	// domain space vector
    	size_t n  = 2;
    	double x = 0.5;
    	double y = 2.0;
    	CPPAD_TESTVECTOR(AD<double>) axy(n);
    	axy[0]      = x;
    	axy[1]      = y;

    	// declare independent variables and start tape recording
    	CppAD::Independent(axy);

    	// range space vector
    	size_t m = 5;
    	CPPAD_TESTVECTOR(AD<double>) az(m);
    	az[0] = CppAD::azmul(axy[0], axy[1]); // azmul(variable, variable)
    	az[1] = CppAD::azmul(axy[0], inf);    // azmul(variable, parameter=inf)
    	az[2] = CppAD::azmul(axy[0], 3.0);    // azmul(variable, parameter=3.0)
    	az[3] = CppAD::azmul(0.0, axy[1]);    // azmul(parameter=0.0, variable)
    	az[4] = CppAD::azmul(4.0, axy[1]);    // azmul(parameter=4.0, variable)

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

    	// check value when x is not zero
    	ok &= NearEqual(az[0] , x * y,  eps, eps);
    	ok &= az[1] == inf;
    	ok &= NearEqual(az[2] , x * 3.0,  eps, eps);
    	ok &= az[3] == 0.0;
    	ok &= NearEqual(az[4] , 4.0 * y,  eps, eps);

    	// check value x is zero and y is infinity
    	CPPAD_TESTVECTOR(double) xy(n), z(m);
    	xy[0] = 0.0;
    	xy[1] = inf;
    	z     = f.Forward(0, xy);
    	ok &= z[0] == 0.0;
    	ok &= z[1] == 0.0;
    	ok &= z[2] == 0.0;
    	ok &= z[3] == 0.0;
    	ok &= z[4] == inf;

    	return ok;
    }

`

Input File: example/azmul.cpp