# include <f2cad/dgamma.hpp>

test_result dgamma(void)
{	bool ok = true;

	// independent variables 
	integer     n  = 1;         // number of independent variables
	double     ell = 3.;
	doublereal  x[1];           // vector of independent variables
	x[0]          = ell+1.;     // value  of independent variables
	f2cad::Independent(n, x);   // declare x as independent variable vector

	// dependent variables 
	integer     m = 1;          // number of dependent variables
	doublereal  f[1];           // vector of dependent variables
	f[0] = f2cad::dgamma_(x+0); // compute value f[0] = Gamma(x[0])
	f2cad::Dependent(m, f);     // declare f as dependent variable vector

	// check the value of f
	ok &= f2cad::near_equal(f2cad::Value(f[0]), 6., 1e-10, 1e-10);

	// Compute derivative of f w.r.t x using f2cad common interface.
	// This general interface works with adolc, cppad, and fadbad.
	// See GetStarted for package specific more efficient code.
	double gamma = 0.577215664901532;
	double p     = f2cad::Partial<doublereal>(0, 0);
	double check = 6. * ( - gamma + 1. + 1./2. + 1./3. ); 
	ok &= f2cad::near_equal(p, check, 1e-10, 1e-10);

	if( ok )
		return test_pass;
	return test_fail;
}