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// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-or-later
// SPDX-FileCopyrightText: Bradley M. Bell <bradbell@seanet.com>
// SPDX-FileContributor: 2003-22 Bradley M. Bell
// ----------------------------------------------------------------------------
/*
@begin zdouble.cpp@@
$spell
zdouble
$$
$section zdouble: Example and Test$$
$srcthisfile%0%// BEGIN C++%// END C++%1%$$
$end
*/
// BEGIN C++
# include <cppad/cppad.hpp>
namespace {
template <class Base> bool test_one(void)
{ bool ok = true;
Base eps99 = 99. * std::numeric_limits<double>::epsilon();
typedef CppAD::AD<Base> a1type;
typedef CppAD::AD<a1type> a2type;
// value during taping
size_t n = 2;
CPPAD_TESTVECTOR(Base) x(n);
x[0] = 0.0;
x[1] = 0.0;
// declare independent variable
CPPAD_TESTVECTOR(a2type) a2x(n);
for (size_t j = 0; j < n; j++)
a2x[j] = a2type( a1type(x[j]) );
Independent(a2x);
// zero and one as a2type values
a2type a2zero = a2type(0.0);
a2type a2one = a2type(1.0);
// h(x) = x[0] / x[1] if x[1] > x[0] else 1.0
a2type h_x = CondExpGt(a2x[1], a2x[0], a2x[0] / a2x[1], a2one);
// f(x) = h(x) if x[0] > 0.0 else 0.0
// = x[0] / x[1] if x[1] > x[0] and x[0] > 0.0
// = 1.0 if x[0] >= x[1] and x[0] > 0.0
// = 0.0 if x[0] <= 0.0
a2type f_x = CondExpGt(a2x[0], a2zero, h_x, a2one);
// define the function f(x)
size_t m = 1;
CPPAD_TESTVECTOR(a2type) a2y(m);
a2y[0] = f_x;
CppAD::ADFun<a1type> af1;
af1.Dependent(a2x, a2y);
// Define function g(x) = gradient of f(x)
CPPAD_TESTVECTOR(a1type) a1x(n), a1z(n), a1w(m);
for (size_t j = 0; j < n; j++)
a1x[j] = a1type(x[j]);
a1w[0] = a1type(1.0);
Independent(a1x);
af1.Forward(0, a1x);
a1z = af1.Reverse(1, a1w);
CppAD::ADFun<Base> g;
g.Dependent(a1x, a1z);
// check result for a case where f(x) = 0.0;
CPPAD_TESTVECTOR(Base) z(2);
x[0] = 0.0;
x[1] = 0.0;
z = g.Forward(0, x);
ok &= z[0] == 0.0;
ok &= z[1] == 0.0;
// check result for a case where f(x) = 1.0;
x[0] = 1.0;
x[1] = 0.5;
z = g.Forward(0, x);
ok &= z[0] == 0.0;
ok &= z[1] == 0.0;
// check result for a case where f(x) = x[0] / x[1];
x[0] = 1.0;
x[1] = 2.0;
z = g.Forward(0, x);
ok &= CppAD::NearEqual(z[0], 1.0/x[1], eps99, eps99);
ok &= CppAD::NearEqual(z[1], - x[0]/(x[1]*x[1]), eps99, eps99);
return ok;
}
bool test_two(void)
{ bool ok = true;
using CppAD::zdouble;
//
zdouble eps = CppAD::numeric_limits<zdouble>::epsilon();
ok &= eps == std::numeric_limits<double>::epsilon();
//
zdouble min = CppAD::numeric_limits<zdouble>::min();
ok &= min == std::numeric_limits<double>::min();
//
zdouble max = CppAD::numeric_limits<zdouble>::max();
ok &= max == std::numeric_limits<double>::max();
//
zdouble nan = CppAD::numeric_limits<zdouble>::quiet_NaN();
ok &= nan != nan;
//
int digits10 = CppAD::numeric_limits<zdouble>::digits10;
ok &= digits10 == std::numeric_limits<double>::digits10;
//
return ok;
}
}
bool zdouble(void)
{ bool ok = true;
using CppAD::AD;
using CppAD::NearEqual;
using CppAD::zdouble;
//
ok &= test_one<zdouble>();
ok &= test_one<double>();
//
ok &= test_two();
//
return ok;
}
// END C++
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