text: /* Boost test/det.cpp
   * test protected and unprotected rounding on an unstable determinant
   *
   * Copyright 2002-2003 Guillaume Melquiond
   *
   * Distributed under the Boost Software License, Version 1.0.
   * (See accompanying file LICENSE_1_0.txt or
   * copy at http://www.boost.org/LICENSE_1_0.txt)
   */
  
  #include <boost/numeric/interval.hpp>
  #include <boost/test/minimal.hpp>
  #include "bugs.hpp"
  
  #define size 8
  
  template<class I>
  void det(I (&mat)[size][size]) {
    for(int i = 0; i < size; i++)
      for(int j = 0; j < size; j++)
        mat[i][j] = I(1) / I(i + j + 1);
  
    for(int i = 0; i < size - 1; i++) {
      int m = i, n = i;
      typename I::base_type v = 0;
      for(int a = i; a < size; a++)
        for(int b = i; b < size; b++) {
          typename I::base_type  w = abs(mat[a][b]).lower();
          if (w > v) { m = a; n = b; v = w; }
        }
      if (n != i)
        for(int a = 0; a < size; a++) {
          I t = mat[a][n];
          mat[a][n] = mat[a][i];
          mat[a][i] = t;
        }
      if (m != i)
        for(int b = i; b < size; b++) {
          I t = mat[m][b];
          mat[m][b] = mat[m][i];
          mat[m][i] = t;
        }
      if (((m + n) & 1) == 1) { };
      I c = mat[i][i];
      for(int j = i + 1; j < size; j++) {
        I f = mat[j][i] / c;
        for(int k = i; k < size; k++)
          mat[j][k] -= f * mat[i][k];
      }
      if (zero_in(c)) return;
    }
  }
  
  namespace my_namespace {
  
  using namespace boost;
  using namespace numeric;
  using namespace interval_lib;
  
  template<class T>
  struct variants {
    typedef interval<T> I_op;
    typedef typename change_rounding<I_op, save_state<rounded_arith_std<T> > >::type I_sp;
    typedef typename unprotect<I_op>::type I_ou;
    typedef typename unprotect<I_sp>::type I_su;
    typedef T type;
  };
  
  }
  
  template<class T>
  bool test() {
    typedef my_namespace::variants<double> types;
    types::I_op mat_op[size][size];
    types::I_sp mat_sp[size][size];
    types::I_ou mat_ou[size][size];
    types::I_su mat_su[size][size];
    det(mat_op);
    det(mat_sp);
    { types::I_op::traits_type::rounding rnd; det(mat_ou); }
    { types::I_sp::traits_type::rounding rnd; det(mat_su); }
    for(int i = 0; i < size; i++)
      for(int j = 0; j < size; j++) {
        typedef types::I_op I;
        I d_op = mat_op[i][j];
        I d_sp = mat_sp[i][j];
        I d_ou = mat_ou[i][j];
        I d_su = mat_su[i][j];
        if (!(equal(d_op, d_sp) && equal(d_sp, d_ou) && equal(d_ou, d_su)))
          return false;
      }
    return true;
  }
  
  int test_main(int, char *[]) {
    BOOST_CHECK(test<float>());
    BOOST_CHECK(test<double>());
    BOOST_CHECK(test<long double>());
  # ifdef __BORLANDC__
    ::detail::ignore_warnings();
  # endif
    return 0;
  }
  