// $Id: atan2.cpp 3785 2016-02-08 12:53:06Z bradbell $
/* --------------------------------------------------------------------------
CppAD: C++ Algorithmic Differentiation: Copyright (C) 2003-15 Bradley M. Bell
CppAD is distributed under multiple licenses. This distribution is under
the terms of the
GNU General Public License Version 3.
A copy of this license is included in the COPYING file of this distribution.
Please visit http://www.coin-or.org/CppAD/ for information on other licenses.
-------------------------------------------------------------------------- */
/*
Old example and test now just used for validation testing.
*/
# include <cppad/cppad.hpp>
# include <cmath>
namespace { // begin empty namespace
bool ad_ad(void)
{ bool ok = true;
using CppAD::AD;
AD< AD<double> > x(2.), y(2.);
AD< AD<double> > z = atan2(y, x);
CppAD::NearEqual( Value( Value(z) ), atan(1.), 1e-10, 1e-10 );
return ok;
}
bool general(void)
{ bool ok = true;
using CppAD::atan;
using CppAD::sin;
using CppAD::cos;
using namespace CppAD;
// independent variable vector
CPPAD_TESTVECTOR(AD<double>) U(1);
U[0] = 1.;
Independent(U);
// a temporary values
AD<double> x = cos(U[0]);
AD<double> y = sin(U[0]);
// dependent variable vector
CPPAD_TESTVECTOR(AD<double>) Z(1);
Z[0] = atan2(y, x);
// create f: U -> Z and vectors used for derivative calculations
ADFun<double> f(U, Z);
CPPAD_TESTVECTOR(double) v(1);
CPPAD_TESTVECTOR(double) w(1);
// check original value (u in first quadrant)
ok &= NearEqual(U[0] , Z[0], 1e-10 , 1e-10);
// check case where u is in second quadrant
v[0] = 3.;
w = f.Forward(0, v);
ok &= NearEqual(w[0] , v[0], 1e-10 , 1e-10);
// check case where u is in third quadrant
v[0] = -3.;
w = f.Forward(0, v);
ok &= NearEqual(w[0] , v[0], 1e-10 , 1e-10);
// check case where u is in fourth quadrant
v[0] = -1.;
w = f.Forward(0, v);
ok &= NearEqual(w[0] , v[0], 1e-10 , 1e-10);
// forward computation of partials w.r.t. u
size_t j;
size_t p = 5;
double jfac = 1.;
double value = 1.;
v[0] = 1.;
for(j = 1; j < p; j++)
{ jfac *= j;
w = f.Forward(j, v);
ok &= NearEqual(jfac*w[0], value, 1e-10 , 1e-10); // d^jz/du^j
v[0] = 0.;
value = 0.;
}
// reverse computation of partials of Taylor coefficients
CPPAD_TESTVECTOR(double) r(p);
w[0] = 1.;
r = f.Reverse(p, w);
jfac = 1.;
value = 1.;
for(j = 0; j < p; j++)
{ ok &= NearEqual(jfac*r[j], value, 1e-10 , 1e-10); // d^jz/du^j
jfac *= (j + 1);
value = 0.;
}
return ok;
}
} // end empty namespace
bool atan2(void)
{ bool ok = true;
ok &= ad_ad();
ok &= general();
return ok;
}