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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
// ----------------------------------------------------------------------------
/*
{xrst_begin compare.cpp}
AD Binary Comparison Operators: Example and Test
################################################
{xrst_literal
// BEGIN C++
// END C++
}
{xrst_end compare.cpp}
*/
// BEGIN C++
# include <cppad/cppad.hpp>
bool Compare(void)
{ bool ok = true;
using CppAD::AD;
using CppAD::NearEqual;
double eps99 = 99.0 * std::numeric_limits<double>::epsilon();
// declare independent variables and start tape recording
size_t n = 2;
double x0 = 0.5;
double x1 = 1.5;
CPPAD_TESTVECTOR(AD<double>) x(n);
x[0] = x0;
x[1] = x1;
CppAD::Independent(x);
// some binary comparison operations
AD<double> p;
if( x[0] < x[1] )
p = x[0]; // values in x choose this case
else
p = x[1];
if( x[0] <= x[1] )
p *= x[0]; // values in x choose this case
else
p *= x[1];
if( x[0] > x[1] )
p *= x[0];
else
p *= x[1]; // values in x choose this case
if( x[0] >= x[1] )
p *= x[0];
else
p *= x[1]; // values in x choose this case
if( x[0] == x[1] )
p *= x[0];
else
p *= x[1]; // values in x choose this case
if( x[0] != x[1] )
p *= x[0]; // values in x choose this case
else
p *= x[1];
// dependent variable vector
size_t m = 1;
CPPAD_TESTVECTOR(AD<double>) y(m);
y[0] = p;
// create f: x -> y and stop tape recording
CppAD::ADFun<double> f(x, y);
// check value
ok &= NearEqual(y[0] , x0*x0*x1*x1*x1*x0, eps99, eps99);
// forward computation of partials w.r.t. x[0]
CPPAD_TESTVECTOR(double) dx(n);
CPPAD_TESTVECTOR(double) dy(m);
dx[0] = 1.;
dx[1] = 0.;
dy = f.Forward(1, dx);
ok &= NearEqual(dy[0], 3.*x0*x0*x1*x1*x1, eps99, eps99);
// forward computation of partials w.r.t. x[1]
dx[0] = 0.;
dx[1] = 1.;
dy = f.Forward(1, dx);
ok &= NearEqual(dy[0], 3.*x0*x0*x1*x1*x0, eps99, eps99);
// reverse computation of derivative of y[0]
CPPAD_TESTVECTOR(double) w(m);
CPPAD_TESTVECTOR(double) dw(n);
w[0] = 1.;
dw = f.Reverse(1, w);
ok &= NearEqual(dw[0], 3.*x0*x0*x1*x1*x1, eps99, eps99);
ok &= NearEqual(dw[1], 3.*x0*x0*x1*x1*x0, eps99, eps99);
return ok;
}
// END C++
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