// N4606 Committee Draft, Standard for Programming Language C++
// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/n4606.pdf 
#define msg "p345.cpp(165)14 Templates [temp]"
// Edited by Dr. Ogawa Kiyoshi. Compile procedure and results record.

#include <iostream>
#include <boost/numeric/ublas/hermitian.hpp>
#include <boost/numeric/ublas/io.hpp>

using namespace boost::numeric::ublas;

template<class T>
constexpr T pi = T(3.1415926535897932385L);
template<class T>
T circular_area(T r) {
return pi<T> * r * r;
}
struct matrix_constants {
template<class T>
using pauli = hermitian_matrix<T, 2>;
template<class T>
constexpr pauli<T> sigma1 = { { 0, 1 }, { 1, 0 } };
template<class T>
constexpr pauli<T> sigma2 = { { 0, -1i }, { 1i, 0 } };
template<class T>
constexpr pauli<T> sigma3 = { { 1, 0 }, { 0, -1 } };
};

int main(){
  std::cout<< msg << std::endl;
  return EXIT_SUCCESS;
}

#!/bin/sh
echo "$ clang++ $1.cpp"
clang++ $1.cpp -std=c++17 -I=/usr/local/Cellar/boost/1.67.0_1/include  -stdlib=libc++ -o $1l
if [  -e $1l ]; then
./$1l $2
fi
echo "\r"
echo "$ g++-7 $1.cpp"
g++-7 $1.cpp  -std=c++17 -I=/usr/local/Cellar/boost/1.67.0_1/include -o $1g
if [  -e $1g ]; then
./$1g $2
fi

$ brew install boost
$ ./cpp17l.sh p345
$ clang++ p345.cpp
p345.cpp:8:17: error: use of undeclared identifier 'boost'
using namespace boost::numeric::ublas;
                ^
p345.cpp:19:15: error: no template named 'hermitian_matrix'
using pauli = hermitian_matrix<T, 2>;
              ^
p345.cpp:21:11: error: no template named 'pauli'
constexpr pauli<T> sigma1 = { { 0, 1 }, { 1, 0 } };
          ^
p345.cpp:21:1: error: non-static data member cannot be constexpr; did you intend to make it static?
constexpr pauli<T> sigma1 = { { 0, 1 }, { 1, 0 } };
^
static 
p345.cpp:23:11: error: no template named 'pauli'
constexpr pauli<T> sigma2 = { { 0, -1i }, { 1i, 0 } };
          ^
p345.cpp:23:1: error: non-static data member cannot be constexpr; did you intend to make it static?
constexpr pauli<T> sigma2 = { { 0, -1i }, { 1i, 0 } };
^
static 
p345.cpp:25:11: error: no template named 'pauli'
constexpr pauli<T> sigma3 = { { 1, 0 }, { 0, -1 } };
          ^
p345.cpp:25:1: error: non-static data member cannot be constexpr; did you intend to make it static?
constexpr pauli<T> sigma3 = { { 1, 0 }, { 0, -1 } };
^
static 
8 errors generated.

$ g++-7 p345.cpp
p345.cpp:8:17: error: 'boost' has not been declared
 using namespace boost::numeric::ublas;
                 ^~~~~
p345.cpp:8:33: error: 'ublas' is not a namespace-name
 using namespace boost::numeric::ublas;
                                 ^~~~~
p345.cpp:8:38: error: expected namespace-name before ';' token
 using namespace boost::numeric::ublas;
                                      ^
p345.cpp:19:15: error: 'hermitian_matrix' does not name a type
 using pauli = hermitian_matrix<T, 2>;
               ^~~~~~~~~~~~~~~~
p345.cpp:21:11: error: 'pauli' does not name a type
 constexpr pauli<T> sigma1 = { { 0, 1 }, { 1, 0 } };
           ^~~~~
p345.cpp:23:11: error: 'pauli' does not name a type
 constexpr pauli<T> sigma2 = { { 0, -1i }, { 1i, 0 } };
           ^~~~~
p345.cpp:25:11: error: 'pauli' does not name a type
 constexpr pauli<T> sigma3 = { { 1, 0 }, { 0, -1 } };
           ^~~~~