#define pi 3.14159 // Predefine pi

#ifndef HAVE_USEFUL_FUNCTIONS_HH
#define HAVE_USEFUL_FUNCTIONS_HH


#ifdef __CPLUSPLUS
template <class return_t>
template <class class_t>
typedef class_t &classref_t;
#else
#define inline			// strip from pre-processed file
#define return_t double
#define class_t  double
typedef class_t  classref_t;
#endif // __CPLUSPLUS

#ifndef MTT_UNUSED
#ifdef __GNUC__
#define MTT_UNUSED __attribute__ ((unused))
#else
#define MTT_UNUSED
#endif // __GNUC__
#endif // MTT_UNUSED



// == Declarations ==

// - Template functions -

static inline return_t max         (const classref_t x1, const classref_t x2) MTT_UNUSED;
static inline return_t min         (const classref_t x1, const classref_t x2) MTT_UNUSED;
static inline return_t nonsingular (const classref_t x) MTT_UNUSED;
static inline return_t sign        (const classref_t x) MTT_UNUSED;

// - Octave functions -
#ifdef __CPLUSPLUS
static inline Matrix	   ones    (const int r = 1, const int c = 1) MTT_UNUSED;
static inline ColumnVector nozeros (const ColumnVector v0, const double tol = 0.0) MTT_UNUSED;
static inline ColumnVector zeros   (const int r) MTT_UNUSED;
static inline Matrix 	   zeros   (const int r, const int c) MTT_UNUSED;
#endif // __CPLUSPLUS



// == Defininitions ==

// - Template functions -

static inline return_t
max (const classref_t x1, const classref_t x2)
{
  return static_cast<return_t>((x1 >= x2) ? x1 : (x1 < x2) ? x2 : 0);
}

static inline return_t
min (const classref_t x1, const classref_t x2)
{
  return static_cast<return_t>((x1 <= x2) ? x1 : (x1 > x2) ? x2 : 0);
}

static inline return_t
nonsingular (const classref_t x)
{
  return static_cast<return_t>((x == 0) ? 1.0e-30 : x);
}

static inline return_t
sign (const classref_t x)
{
  return static_cast<return_t>((x > 0) ? +1 : (x < 0) ? -1 : 0);
}


// - Octave functions -
#ifdef __CPLUSPLUS
Matrix
ones (const int r = 1, const int c = 1)
{
  Matrix m (r, c, 1.0);
  return m;
}

ColumnVector
nozeros (const ColumnVector v0, const double tol = 0.0)
{
  ColumnVector v (v0.length ());
  register int i, j;
  for (i = j = 0; i < v.length (); i++)
    if (tol < abs (v0 (i)))
      {
	v (j) = v0 (i);
	j++;
      }
  if (0 == j)
    {
      return *new ColumnVector ();
    }
  else
    {
      return (v.extract (0, --j));
    }
}

ColumnVector
zeros (const int r)
{
  ColumnVector v (r, 0.0);
  return v;
}

Matrix
zeros (const int r, const int c)
{
  Matrix m (r, c, 0.0);
  return m;
}
#endif __CPLUSPLUS



#endif // HAVE_USEFUL_FUNCTIONS_HH