#! /bin/bash -e
# vim: set expandtab:
# 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
# ----------------------------------------------------------------------------
name=`echo $0 | sed -e 's|^bug/||' -e 's|\.sh$||'`
if [ "$0" != "bug/$name.sh" ]
then
   echo 'usage: bug/pow.sh'
   exit 1
fi
# -----------------------------------------------------------------------------
if [ -e build/bug ]
then
   rm -r build/bug
fi
mkdir -p build/bug
cd build/bug
# cmake ../..
# -----------------------------------------------------------------------------
cat << EOF
Issue 43:
f(x) = (x^0.5) * (x^0.5) = x, and differentiate at x = 0.
Expect some NaN, Inf, or possibly one, but not zero.
EOF
cat << EOF > $name.cpp
# include <cstdio>
# include "cppad/cppad.hpp"


int main(int argc, char** argv)
{  bool ok = true;

   using std::cout;
   using CppAD::AD;
   using CppAD::vector;
   //
   vector< double> x(1), y(1), w(1), dw(1);
   vector< AD<double> > ax(1), ay(1);
   //
   ax[0] = 0.0;
   //
   CppAD::Independent(ax);
   ay[0] = pow(ax[0], 0.5) * pow(ax[0], 0.5);
   CppAD::ADFun<double> f(ax, ay);
   //
   x[0]  = 0.0;
   y     = f.Forward(0, x);
   w[0]  = 1.0;
   dw    = f.Reverse(1, w);
   //
   cout << "dw = " << dw << "\n";
   //
   ok &= y[0] == 0.0;
   ok &= dw[0] == 1.0 || ! std::isfinite( dw[0] );
   //
   if( ! ok )
      return 1;
   return 0;
}
EOF
cxx_flags='-Wall -pedantic-errors -std=c++11 -Wshadow -Wconversion -g -O0'
eigen_dir="$HOME/prefix/eigen/include"
echo "g++ -I../../include -isystem $eigen_dir $cxx_flags $name.cpp -o $name"
g++ -I../../include -isystem $eigen_dir $cxx_flags $name.cpp -o $name
#
echo "build/bug/$name"
if ! ./$name
then
   echo
   echo "build/bug/$name: Error"
   exit 1
fi
echo
# -----------------------------------------------------------------------------
echo "bug/$name.sh: OK"
exit 0