/*

  * Copyright (c) 1999

  * Silicon Graphics Computer Systems, Inc.

  *

  * Copyright (c) 1999

  * Boris Fomitchev

  *

  * This material is provided "as is", with absolutely no warranty expressed

  * or implied. Any use is at your own risk.

  *

  * Permission to use or copy this software for any purpose is hereby granted

  * without fee, provided the above notices are retained on all copies.

  * Permission to modify the code and to distribute modified code is granted,

  * provided the above notices are retained, and a notice that the code was

  * modified is included with the above copyright notice.

  *

  */

 #ifndef _STLP_VALARRAY_H

 #define _STLP_VALARRAY_H

 #ifndef _STLP_INTERNAL_CMATH

 #  include <stl/_cmath.h>

 #endif

 #ifndef _STLP_INTERNAL_NEW

 #  include <stl/_new.h>

 #endif

 #ifndef _STLP_INTERNAL_ALGO_H

 #  include <stl/_algo.h>

 #endif

 #ifndef _STLP_INTERNAL_NUMERIC_H

 #  include <stl/_numeric.h>

 #endif

 #ifndef _STLP_INTERNAL_LIMITS

 #  include <stl/_limits.h>

 #endif

 /* As we only need the _STLP_ASSERT macro from _debug.h we test it to include _debug.h */

 #ifndef _STLP_ASSERT

 #  include <stl/debug/_debug.h>

 #endif

 _STLP_BEGIN_NAMESPACE

 class slice;

 class gslice;

 template <class _Tp> class valarray;

 typedef valarray<bool>    _Valarray_bool;

 typedef valarray<size_t>  _Valarray_size_t;

 template <class _Tp> class slice_array;

 template <class _Tp> class gslice_array;

 template <class _Tp> class mask_array;

 template <class _Tp> class indirect_array;

 //----------------------------------------------------------------------

 // class valarray

 // Base class to handle memory allocation and deallocation.  We can't just

 // use vector<>, because vector<bool> would be unsuitable as an internal

 // representation for valarray<bool>.

 template <class _Tp>

 struct _Valarray_base

 {

   _Tp*   _M_first;

   size_t _M_size;

   _Valarray_base() : _M_first(0), _M_size(0) {}

   _Valarray_base(size_t __n) : _M_first(0), _M_size(0) { _M_allocate(__n); }

   ~_Valarray_base() { _M_deallocate(); }

   void _M_allocate(size_t __n) {

     if (__n != 0) {

       _M_first = __STATIC_CAST(_Tp*, (malloc(__n * sizeof(_Tp))));

       _M_size  = __n;

 #if !defined(_STLP_NO_BAD_ALLOC) && defined(_STLP_USE_EXCEPTIONS)

       if (_M_first == 0) {

         _M_size = 0;

         throw _STLP_STD::bad_alloc();

       }

 #endif

     }

     else {

       _M_first = 0;

       _M_size = 0;

     }

   }

   void _M_deallocate() {

     free(_M_first);

     _M_first = 0;

     _M_size = 0;

   }

 };

 template <class _Tp>

 class valarray : private _Valarray_base<_Tp>

 {

   friend class gslice;

 public:

   typedef _Tp value_type;

   // Basic constructors

   valarray() : _Valarray_base<_Tp>() {}

   explicit valarray(size_t __n) : _Valarray_base<_Tp>(__n)

     { uninitialized_fill_n(this->_M_first, this->_M_size, _STLP_DEFAULT_CONSTRUCTED(value_type)); }

   valarray(const value_type& __x, size_t __n) : _Valarray_base<_Tp>(__n)

     { uninitialized_fill_n(this->_M_first, this->_M_size, __x); }

   valarray(const value_type* __p, size_t __n) : _Valarray_base<_Tp>(__n)

     { uninitialized_copy(__p, __p + __n, this->_M_first); }

   valarray(const valarray<_Tp>& __x) : _Valarray_base<_Tp>(__x._M_size) {

     uninitialized_copy(__x._M_first, __x._M_first + __x._M_size,

                        this->_M_first);

   }

   // Constructors from auxiliary array types

   valarray(const slice_array<_Tp>&);

   valarray(const gslice_array<_Tp>&);

   valarray(const mask_array<_Tp>&);

   valarray(const indirect_array<_Tp>&);

   // Destructor

   ~valarray() { _STLP_STD::_Destroy_Range(this->_M_first, this->_M_first + this->_M_size); }

   // Extension: constructor that doesn't initialize valarray elements to a

   // specific value.  This is faster for types such as int and double.

 private:

   void _M_initialize(const __true_type&) {}

   void _M_initialize(const __false_type&)

     { uninitialized_fill_n(this->_M_first, this->_M_size, _STLP_DEFAULT_CONSTRUCTED(_Tp)); }

 public:

   struct _NoInit {};

   valarray(size_t __n, _NoInit) : _Valarray_base<_Tp>(__n) {

     typedef typename __type_traits<_Tp>::has_trivial_default_constructor _Is_Trivial;

     _M_initialize(_Is_Trivial());

   }

 public:                         // Assignment

   // Basic assignment.  Note that 'x = y' is undefined if x.size() != y.size()

   valarray<_Tp>& operator=(const valarray<_Tp>& __x) {

     _STLP_ASSERT(__x.size() == this->size())

     if (this != &__x)

       copy(__x._M_first, __x._M_first + __x._M_size, this->_M_first);

     return *this;

   }

   // Scalar assignment

   valarray<_Tp>& operator=(const value_type& __x) {

     fill_n(this->_M_first, this->_M_size, __x);

     return *this;

   }

   // Assignment of auxiliary array types

   valarray<_Tp>& operator=(const slice_array<_Tp>&);

   valarray<_Tp>& operator=(const gslice_array<_Tp>&);

   valarray<_Tp>& operator=(const mask_array<_Tp>&);

   valarray<_Tp>& operator=(const indirect_array<_Tp>&);

 public:                         // Element access

   value_type  operator[](size_t __n) const { return this->_M_first[__n]; }

   value_type& operator[](size_t __n)       { return this->_M_first[__n]; }

   size_t size() const { return this->_M_size; }

 public:                         // Subsetting operations with auxiliary type

   valarray<_Tp>            operator[](slice) const;

   slice_array<_Tp>    operator[](slice);

   valarray<_Tp>            operator[](const gslice&) const;

   gslice_array<_Tp>   operator[](const gslice&);

   valarray<_Tp>            operator[](const _Valarray_bool&) const;

   mask_array<_Tp>     operator[](const _Valarray_bool&);

   valarray<_Tp>            operator[](const _Valarray_size_t&) const;

   indirect_array<_Tp> operator[](const _Valarray_size_t&);

 public:                         // Unary operators.

   valarray<_Tp> operator+() const { return *this; }

   valarray<_Tp> operator-() const {

     valarray<_Tp> __tmp(this->size(), _NoInit());

     for (size_t __i = 0; __i < this->size(); ++__i)

       __tmp[__i] = -(*this)[__i];

     return __tmp;

   }

   valarray<_Tp> operator~() const {

     valarray<_Tp> __tmp(this->size(), _NoInit());

     for (size_t __i = 0; __i < this->size(); ++__i)

       __tmp[__i] = ~(*this)[__i];

     return __tmp;

   }

   _Valarray_bool operator!() const;

 public:                         // Scalar computed assignment.

   valarray<_Tp>& operator*= (const value_type& __x) {

     for (size_t __i = 0; __i < this->size(); ++__i)

       (*this)[__i] *= __x;

     return *this;

   }

   valarray<_Tp>& operator/= (const value_type& __x) {

     for (size_t __i = 0; __i < this->size(); ++__i)

       (*this)[__i] /= __x;

     return *this;

   }

   valarray<_Tp>& operator%= (const value_type& __x) {

     for (size_t __i = 0; __i < this->size(); ++__i)

       (*this)[__i] %= __x;

     return *this;

   }

   valarray<_Tp>& operator+= (const value_type& __x) {

     for (size_t __i = 0; __i < this->size(); ++__i)

       (*this)[__i] += __x;

     return *this;

   }

   valarray<_Tp>& operator-= (const value_type& __x) {

     for (size_t __i = 0; __i < this->size(); ++__i)

       (*this)[__i] -= __x;

     return *this;

   }

   valarray<_Tp>& operator^= (const value_type& __x) {

     for (size_t __i = 0; __i < this->size(); ++__i)

       (*this)[__i] ^= __x;

     return *this;

   }

   valarray<_Tp>& operator&= (const value_type& __x) {

     for (size_t __i = 0; __i < this->size(); ++__i)

       (*this)[__i] &= __x;

     return *this;

   }

   valarray<_Tp>& operator|= (const value_type& __x) {

     for (size_t __i = 0; __i < this->size(); ++__i)

       (*this)[__i] |= __x;

     return *this;

   }

   valarray<_Tp>& operator<<= (const value_type& __x) {

     for (size_t __i = 0; __i < this->size(); ++__i)

       (*this)[__i] <<= __x;

     return *this;

   }

   valarray<_Tp>& operator>>= (const value_type& __x) {

     for (size_t __i = 0; __i < this->size(); ++__i)

       (*this)[__i] >>= __x;

     return *this;

   }

 public:                         // Array computed assignment.

   valarray<_Tp>& operator*= (const valarray<_Tp>& __x) {

     for (size_t __i = 0; __i < this->size(); ++__i)

       (*this)[__i] *= __x[__i];

     return *this;

   }

   valarray<_Tp>& operator/= (const valarray<_Tp>& __x) {

     for (size_t __i = 0; __i < this->size(); ++__i)

       (*this)[__i] /= __x[__i];

     return *this;

   }

   valarray<_Tp>& operator%= (const valarray<_Tp>& __x) {

     for (size_t __i = 0; __i < this->size(); ++__i)

       (*this)[__i] %= __x[__i];

     return *this;

   }

   valarray<_Tp>& operator+= (const valarray<_Tp>& __x) {

     for (size_t __i = 0; __i < this->size(); ++__i)

       (*this)[__i] += __x[__i];

     return *this;

   }

   valarray<_Tp>& operator-= (const valarray<_Tp>& __x) {

     for (size_t __i = 0; __i < this->size(); ++__i)

       (*this)[__i] -= __x[__i];

     return *this;

   }

   valarray<_Tp>& operator^= (const valarray<_Tp>& __x) {

     for (size_t __i = 0; __i < this->size(); ++__i)

       (*this)[__i] ^= __x[__i];

     return *this;

   }

   valarray<_Tp>& operator&= (const valarray<_Tp>& __x) {

     for (size_t __i = 0; __i < this->size(); ++__i)

       (*this)[__i] &= __x[__i];

     return *this;

   }

   valarray<_Tp>& operator|= (const valarray<_Tp>& __x) {

     for (size_t __i = 0; __i < this->size(); ++__i)

       (*this)[__i] |= __x[__i];

     return *this;

   }

   valarray<_Tp>& operator<<= (const valarray<_Tp>& __x) {

     for (size_t __i = 0; __i < this->size(); ++__i)

       (*this)[__i] <<= __x[__i];

     return *this;

   }

   valarray<_Tp>& operator>>= (const valarray<_Tp>& __x) {

     for (size_t __i = 0; __i < this->size(); ++__i)

       (*this)[__i] >>= __x[__i];

     return *this;

   }

 public:                         // Other member functions.

   // The result is undefined for zero-length arrays

   value_type sum() const {

     return accumulate(this->_M_first + 1, this->_M_first + this->_M_size,

                       (*this)[0]);

   }

   // The result is undefined for zero-length arrays

   value_type (min) () const {

     return *min_element(this->_M_first + 0, this->_M_first + this->_M_size);

   }

   value_type (max) () const {

     return *max_element(this->_M_first + 0, this->_M_first + this->_M_size);

   }

   valarray<_Tp> shift(int __n) const;

   valarray<_Tp> cshift(int __n) const;

   valarray<_Tp> apply(value_type __f(value_type)) const {

     valarray<_Tp> __tmp(this->size());

     transform(this->_M_first + 0, this->_M_first + this->_M_size, __tmp._M_first,

               __f);

     return __tmp;

   }

   valarray<_Tp> apply(value_type __f(const value_type&)) const {

     valarray<_Tp> __tmp(this->size());

     transform(this->_M_first + 0, this->_M_first + this->_M_size, __tmp._M_first,

               __f);

     return __tmp;

   }

   void resize(size_t __n, value_type __x = value_type()) {

     _STLP_STD::_Destroy_Range(this->_M_first, this->_M_first + this->_M_size);

     _Valarray_base<_Tp>::_M_deallocate();

     _Valarray_base<_Tp>::_M_allocate(__n);

     uninitialized_fill_n(this->_M_first, this->_M_size, __x);

   }

 };

 //----------------------------------------------------------------------

 // valarray non-member functions.

 // Binary arithmetic operations between two arrays.  Behavior is

 // undefined if the two arrays do not have the same length.

 template <class _Tp>

 inline valarray<_Tp>  _STLP_CALL operator*(const valarray<_Tp>& __x,

                                            const valarray<_Tp>& __y) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] * __y[__i];

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp>  _STLP_CALL operator/(const valarray<_Tp>& __x,

                                            const valarray<_Tp>& __y) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] / __y[__i];

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp>  _STLP_CALL operator%(const valarray<_Tp>& __x,

                                            const valarray<_Tp>& __y) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] % __y[__i];

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp>  _STLP_CALL operator+(const valarray<_Tp>& __x,

                                            const valarray<_Tp>& __y) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] + __y[__i];

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp>  _STLP_CALL operator-(const valarray<_Tp>& __x,

                                            const valarray<_Tp>& __y) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] - __y[__i];

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator^(const valarray<_Tp>& __x,

                                const valarray<_Tp>& __y) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] ^ __y[__i];

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator&(const valarray<_Tp>& __x,

                                const valarray<_Tp>& __y) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] & __y[__i];

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator|(const valarray<_Tp>& __x,

                                const valarray<_Tp>& __y) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] | __y[__i];

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator<<(const valarray<_Tp>& __x,

                                const valarray<_Tp>& __y) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] << __y[__i];

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator>>(const valarray<_Tp>& __x,

                                const valarray<_Tp>& __y) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] >> __y[__i];

   return __tmp;

 }

 // Binary arithmetic operations between an array and a scalar.

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator*(const valarray<_Tp>& __x, const _Tp& __c) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i]  * __c;

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator*(const _Tp& __c, const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __c * __x[__i];

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator/(const valarray<_Tp>& __x, const _Tp& __c) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i]  / __c;

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator/(const _Tp& __c, const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __c / __x[__i];

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator%(const valarray<_Tp>& __x, const _Tp& __c) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i]  % __c;

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator%(const _Tp& __c, const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __c % __x[__i];

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator+(const valarray<_Tp>& __x, const _Tp& __c) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i]  + __c;

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator+(const _Tp& __c, const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __c + __x[__i];

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator-(const valarray<_Tp>& __x, const _Tp& __c) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i]  - __c;

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator-(const _Tp& __c, const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __c - __x[__i];

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator^(const valarray<_Tp>& __x, const _Tp& __c) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i]  ^ __c;

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator^(const _Tp& __c, const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __c ^ __x[__i];

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator&(const valarray<_Tp>& __x, const _Tp& __c) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i]  & __c;

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator&(const _Tp& __c, const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __c & __x[__i];

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator|(const valarray<_Tp>& __x, const _Tp& __c) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i]  | __c;

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator|(const _Tp& __c, const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __c | __x[__i];

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator<<(const valarray<_Tp>& __x, const _Tp& __c) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i]  << __c;

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator<<(const _Tp& __c, const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __c << __x[__i];

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator>>(const valarray<_Tp>& __x, const _Tp& __c) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i]  >> __c;

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> _STLP_CALL operator>>(const _Tp& __c, const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __c >> __x[__i];

   return __tmp;

 }

 // Binary logical operations between two arrays.  Behavior is undefined

 // if the two arrays have different lengths.  Note that operator== does

 // not do what you might at first expect.

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator==(const valarray<_Tp>& __x,

                                  const valarray<_Tp>& __y)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] == __y[__i];

   return __tmp;

 }

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator<(const valarray<_Tp>& __x,

                                 const valarray<_Tp>& __y)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] < __y[__i];

   return __tmp;

 }

 #ifdef _STLP_USE_SEPARATE_RELOPS_NAMESPACE

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator!=(const valarray<_Tp>& __x,

                                  const valarray<_Tp>& __y)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] != __y[__i];

   return __tmp;

 }

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator>(const valarray<_Tp>& __x,

                                 const valarray<_Tp>& __y)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] > __y[__i];

   return __tmp;

 }

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator<=(const valarray<_Tp>& __x,

                                  const valarray<_Tp>& __y)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] <= __y[__i];

   return __tmp;

 }

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator>=(const valarray<_Tp>& __x,

                                  const valarray<_Tp>& __y)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] >= __y[__i];

   return __tmp;

 }

 #endif /* _STLP_USE_SEPARATE_RELOPS_NAMESPACE */

 // fbp : swap ?

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator&&(const valarray<_Tp>& __x,

                                  const valarray<_Tp>& __y)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] && __y[__i];

   return __tmp;

 }

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator||(const valarray<_Tp>& __x,

                                  const valarray<_Tp>& __y)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] || __y[__i];

   return __tmp;

 }

 // Logical operations between an array and a scalar.

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator==(const valarray<_Tp>& __x, const _Tp& __c)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] == __c;

   return __tmp;

 }

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator==(const _Tp& __c, const valarray<_Tp>& __x)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __c == __x[__i];

   return __tmp;

 }

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator!=(const valarray<_Tp>& __x, const _Tp& __c)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] != __c;

   return __tmp;

 }

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator!=(const _Tp& __c, const valarray<_Tp>& __x)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __c != __x[__i];

   return __tmp;

 }

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator<(const valarray<_Tp>& __x, const _Tp& __c)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] < __c;

   return __tmp;

 }

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator<(const _Tp& __c, const valarray<_Tp>& __x)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __c < __x[__i];

   return __tmp;

 }

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator>(const valarray<_Tp>& __x, const _Tp& __c)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] > __c;

   return __tmp;

 }

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator>(const _Tp& __c, const valarray<_Tp>& __x)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __c > __x[__i];

   return __tmp;

 }

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator<=(const valarray<_Tp>& __x, const _Tp& __c)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i]  <= __c;

   return __tmp;

 }

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator<=(const _Tp& __c, const valarray<_Tp>& __x)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __c <= __x[__i];

   return __tmp;

 }

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator>=(const valarray<_Tp>& __x, const _Tp& __c)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] >= __c;

   return __tmp;

 }

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator>=(const _Tp& __c, const valarray<_Tp>& __x)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __c >= __x[__i];

   return __tmp;

 }

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator&&(const valarray<_Tp>& __x, const _Tp& __c)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] && __c;

   return __tmp;

 }

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator&&(const _Tp& __c, const valarray<_Tp>& __x)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __c && __x[__i];

   return __tmp;

 }

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator||(const valarray<_Tp>& __x, const _Tp& __c)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __x[__i] || __c;

   return __tmp;

 }

 template <class _Tp>

 inline _Valarray_bool _STLP_CALL operator||(const _Tp& __c, const valarray<_Tp>& __x)

 {

   _Valarray_bool __tmp(__x.size(), _Valarray_bool::_NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = __c || __x[__i];

   return __tmp;

 }

 // valarray "transcendentals" (the list includes abs and sqrt, which,

 // of course, are not transcendental).

 template <class _Tp>

 inline valarray<_Tp> abs(const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = ::abs(__x[__i]);

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> acos(const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = ::acos(__x[__i]);

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> asin(const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = ::asin(__x[__i]);

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> atan(const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = ::atan(__x[__i]);

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> atan2(const valarray<_Tp>& __x,

                            const valarray<_Tp>& __y) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = ::atan2(__x[__i], __y[__i]);

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> atan2(const valarray<_Tp>& __x, const _Tp& __c) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = ::atan2(__x[__i], __c);

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> atan2(const _Tp& __c, const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = ::atan2(__c, __x[__i]);

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> cos(const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = ::cos(__x[__i]);

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> cosh(const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = ::cosh(__x[__i]);

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> exp(const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = ::exp(__x[__i]);

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> log(const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = ::log(__x[__i]);

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> log10(const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = ::log10(__x[__i]);

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> pow(const valarray<_Tp>& __x,

                          const valarray<_Tp>& __y) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = ::pow(__x[__i], __y[__i]);

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> pow(const valarray<_Tp>& __x, const _Tp& __c) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = ::pow(__x[__i], __c);

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> pow(const _Tp& __c, const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = ::pow(__c, __x[__i]);

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> sin(const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = ::sin(__x[__i]);

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> sinh(const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = ::sinh(__x[__i]);

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> sqrt(const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = ::sqrt(__x[__i]);

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> tan(const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = ::tan(__x[__i]);

   return __tmp;

 }

 template <class _Tp>

 inline valarray<_Tp> tanh(const valarray<_Tp>& __x) {

   typedef typename valarray<_Tp>::_NoInit _NoInit;

   valarray<_Tp> __tmp(__x.size(), _NoInit());

   for (size_t __i = 0; __i < __x.size(); ++__i)

     __tmp[__i] = ::tanh(__x[__i]);

   return __tmp;

 }

 //----------------------------------------------------------------------

 // slice and slice_array

 class slice {

 public:

   slice() : _M_start(0), _M_length(0), _M_stride(0) {}

   slice(size_t __start, size_t __length, size_t __stride)

     : _M_start(__start), _M_length(__length), _M_stride(__stride)

     {}

   __TRIVIAL_DESTRUCTOR(slice)

   size_t start()  const { return _M_start; }

   size_t size()   const { return _M_length; }

   size_t stride() const { return _M_stride; }

 private:

   size_t _M_start;

   size_t _M_length;

   size_t _M_stride;

 };

 template <class _Tp>

 class slice_array {

   friend class valarray<_Tp>;

 public:

   typedef _Tp value_type;

   void operator=(const valarray<value_type>& __x) const {

     size_t __index = _M_slice.start();

     for (size_t __i = 0;

          __i < _M_slice.size();

          ++__i, __index += _M_slice.stride())

       _M_array[__index] = __x[__i];

   }

   void operator*=(const valarray<value_type>& __x) const {

     size_t __index = _M_slice.start();

     for (size_t __i = 0;

          __i < _M_slice.size();

          ++__i, __index += _M_slice.stride())

       _M_array[__index] *= __x[__i];

   }

   void operator/=(const valarray<value_type>& __x) const {

     size_t __index = _M_slice.start();

     for (size_t __i = 0;

          __i < _M_slice.size();

          ++__i, __index += _M_slice.stride())

       _M_array[__index] /= __x[__i];

   }

   void operator%=(const valarray<value_type>& __x) const {

     size_t __index = _M_slice.start();

     for (size_t __i = 0;

          __i < _M_slice.size();

          ++__i, __index += _M_slice.stride())

       _M_array[__index] %= __x[__i];

   }

   void operator+=(const valarray<value_type>& __x) const {

     size_t __index = _M_slice.start();

     for (size_t __i = 0;

          __i < _M_slice.size();

          ++__i, __index += _M_slice.stride())

       _M_array[__index] += __x[__i];

   }

   void operator-=(const valarray<value_type>& __x) const {

     size_t __index = _M_slice.start();

     for (size_t __i = 0;

          __i < _M_slice.size();

          ++__i, __index += _M_slice.stride())

       _M_array[__index] -= __x[__i];

   }

   void operator^=(const valarray<value_type>& __x) const {

     size_t __index = _M_slice.start();

     for (size_t __i = 0;

          __i < _M_slice.size();

          ++__i, __index += _M_slice.stride())

       _M_array[__index] ^= __x[__i];

   }

   void operator&=(const valarray<value_type>& __x) const {

     size_t __index = _M_slice.start();

     for (size_t __i = 0;

          __i < _M_slice.size();

          ++__i, __index += _M_slice.stride())

       _M_array[__index] &= __x[__i];

   }

   void operator|=(const valarray<value_type>& __x) const {

     size_t __index = _M_slice.start();

     for (size_t __i = 0;

          __i < _M_slice.size();

          ++__i, __index += _M_slice.stride())

       _M_array[__index] |= __x[__i];

   }

   void operator<<=(const valarray<value_type>& __x) const {

     size_t __index = _M_slice.start();

     for (size_t __i = 0;

          __i < _M_slice.size();

          ++__i, __index += _M_slice.stride())

       _M_array[__index] <<= __x[__i];

   }

   void operator>>=(const valarray<value_type>& __x) const {

     size_t __index = _M_slice.start();

     for (size_t __i = 0;

          __i < _M_slice.size();

          ++__i, __index += _M_slice.stride())

       _M_array[__index] >>= __x[__i];

   }

   void operator=(const value_type& __c) /*const could be const but standard says NO (26.3.5.4-1)*/ {

     size_t __index = _M_slice.start();

     for (size_t __i = 0;

          __i < _M_slice.size();

          ++__i, __index += _M_slice.stride())

       _M_array[__index] = __c;

   }

   ~slice_array() {}

 private:

   slice_array(const slice& __slice, valarray<_Tp>& __array)

     : _M_slice(__slice), _M_array(__array)

     {}

   slice          _M_slice;

   valarray<_Tp>& _M_array;

 private:                        // Disable assignment and default constructor

   slice_array();

   slice_array(const slice_array&);

   slice_array& operator=(const slice_array&);

 };

 // valarray member functions dealing with slice and slice_array

 template <class _Tp>

 inline valarray<_Tp>::valarray(const slice_array<_Tp>& __x)

   : _Valarray_base<_Tp>(__x._M_slice.size()) {

   typedef typename __type_traits<_Tp>::has_trivial_default_constructor

           _Is_Trivial;

   _M_initialize(_Is_Trivial());

   *this = __x;

 }

 template <class _Tp>

 inline slice_array<_Tp> valarray<_Tp>::operator[](slice __slice) {

   return slice_array<_Tp>(__slice, *this);

 }

 //----------------------------------------------------------------------

 // gslice and gslice_array

 template <class _Size>

 struct _Gslice_Iter_tmpl;

 class gslice {

   friend struct _Gslice_Iter_tmpl<size_t>;

 public:

   gslice() : _M_start(0), _M_lengths(0), _M_strides(0) {}

   gslice(size_t __start,

          const _Valarray_size_t& __lengths, const _Valarray_size_t& __strides)

     : _M_start(__start), _M_lengths(__lengths), _M_strides(__strides)

     {}

   __TRIVIAL_DESTRUCTOR(gslice)

   size_t start()            const { return _M_start; }

   _Valarray_size_t size()   const { return _M_lengths; }

   _Valarray_size_t stride() const { return _M_strides; }

   // Extension: check for an empty gslice.

   bool _M_empty() const { return _M_lengths.size() == 0; }

   // Extension: number of indices this gslice represents.  (For a degenerate

   // gslice, they're not necessarily all distinct.)

   size_t _M_size() const {

     return !this->_M_empty()

       ? accumulate(_M_lengths._M_first + 1,

                    _M_lengths._M_first + _M_lengths._M_size,

                    _M_lengths[0],

                    multiplies<size_t>())

       : 0;

   }

 # ifndef __HP_aCC

 private:

 # endif

   size_t _M_start;

   _Valarray_size_t _M_lengths;

   _Valarray_size_t _M_strides;

 };

 // This is not an STL iterator.  It is constructed from a gslice, and it

 // steps through the gslice indices in sequence.  See 23.3.6 of the C++

 // standard, paragraphs 2-3, for an explanation of the sequence.  At

 // each step we get two things: the ordinal (i.e. number of steps taken),

 // and the one-dimensional index.

 template <class _Size>

 struct _Gslice_Iter_tmpl {

   _Gslice_Iter_tmpl(const gslice& __gslice)

     : _M_step(0), _M_1d_idx(__gslice.start()),

       _M_indices(size_t(0), __gslice._M_lengths.size()),

       _M_gslice(__gslice)

     {}

   bool _M_done() const { return _M_indices[0] == _M_gslice._M_lengths[0]; }

   bool _M_incr();

   _Size _M_step;

   _Size _M_1d_idx;

   valarray<_Size> _M_indices;

   const gslice& _M_gslice;

 };

 typedef _Gslice_Iter_tmpl<size_t> _Gslice_Iter;

 template <class _Tp>

 class gslice_array {

   friend class valarray<_Tp>;

 public:

   typedef _Tp value_type;

   void operator= (const valarray<value_type>& __x) const {

     if (!_M_gslice._M_empty()) {

       _Gslice_Iter __i(_M_gslice);

       do _M_array[__i._M_1d_idx] = __x[__i._M_step]; while(__i._M_incr());

     }

   }

   void operator*= (const valarray<value_type>& __x) const {

     if (!_M_gslice._M_empty()) {

       _Gslice_Iter __i(_M_gslice);

       do _M_array[__i._M_1d_idx] *= __x[__i._M_step]; while(__i._M_incr());

     }

   }

   void operator/= (const valarray<value_type>& __x) const {

     if (!_M_gslice._M_empty()) {

       _Gslice_Iter __i(_M_gslice);

       do _M_array[__i._M_1d_idx] /= __x[__i._M_step]; while(__i._M_incr());

     }

   }

   void operator%= (const valarray<value_type>& __x) const {

     if (!_M_gslice._M_empty()) {

       _Gslice_Iter __i(_M_gslice);

       do _M_array[__i._M_1d_idx] %= __x[__i._M_step]; while(__i._M_incr());

     }

   }

   void operator+= (const valarray<value_type>& __x) const {

     if (!_M_gslice._M_empty()) {

       _Gslice_Iter __i(_M_gslice);

       do _M_array[__i._M_1d_idx] += __x[__i._M_step]; while(__i._M_incr());

     }

   }

   void operator-= (const valarray<value_type>& __x) const {

     if (!_M_gslice._M_empty()) {

       _Gslice_Iter __i(_M_gslice);

       do _M_array[__i._M_1d_idx] -= __x[__i._M_step]; while(__i._M_incr());

     }

   }

   void operator^= (const valarray<value_type>& __x) const {

     if (!_M_gslice._M_empty()) {

       _Gslice_Iter __i(_M_gslice);

       do _M_array[__i._M_1d_idx] ^= __x[__i._M_step]; while(__i._M_incr());

     }

   }

   void operator&= (const valarray<value_type>& __x) const {

     if (!_M_gslice._M_empty()) {

       _Gslice_Iter __i(_M_gslice);

       do _M_array[__i._M_1d_idx] &= __x[__i._M_step]; while(__i._M_incr());

     }

   }

   void operator|= (const valarray<value_type>& __x) const {

     if (!_M_gslice._M_empty()) {

       _Gslice_Iter __i(_M_gslice);

       do _M_array[__i._M_1d_idx] |= __x[__i._M_step]; while(__i._M_incr());

     }

   }

   void operator<<= (const valarray<value_type>& __x) const {

     if (!_M_gslice._M_empty()) {

       _Gslice_Iter __i(_M_gslice);

       do _M_array[__i._M_1d_idx] <<= __x[__i._M_step]; while(__i._M_incr());

     }

   }

   void operator>>= (const valarray<value_type>& __x) const {

     if (!_M_gslice._M_empty()) {

       _Gslice_Iter __i(_M_gslice);

       do _M_array[__i._M_1d_idx] >>= __x[__i._M_step]; while(__i._M_incr());

     }

   }

   void operator= (const value_type& __c) /*const could be const but standard says NO (26.3.7.4-1)*/ {

     if (!_M_gslice._M_empty()) {

       _Gslice_Iter __i(_M_gslice);

       do _M_array[__i._M_1d_idx] = __c; while(__i._M_incr());

     }

   }

   ~gslice_array() {}

 private:

   gslice_array(const gslice& __gslice, valarray<_Tp>& __array)

     : _M_gslice(__gslice), _M_array(__array)

     {}

   gslice                _M_gslice;

   valarray<value_type>& _M_array;

 private:                        // Disable assignment

   void operator=(const gslice_array<_Tp>&);

 };

 // valarray member functions dealing with gslice and gslice_array.  Note

 // that it is illegal (behavior is undefined) to construct a gslice_array

 // from a degenerate gslice.

 template <class _Tp>

 inline valarray<_Tp>::valarray(const gslice_array<_Tp>& __x)

   : _Valarray_base<_Tp>(__x._M_gslice._M_size()) {

   typedef typename __type_traits<_Tp>::has_trivial_default_constructor

           _Is_Trivial;

   _M_initialize(_Is_Trivial());

   *this = __x;

 }

 template <class _Tp>

 inline gslice_array<_Tp> valarray<_Tp>::operator[](const gslice& __slice) {

   return gslice_array<_Tp>(__slice, *this);

 }

 //----------------------------------------------------------------------

 // mask_array

 template <class _Tp>

 class mask_array {

   friend class valarray<_Tp>;

 public:

   typedef _Tp value_type;

   void operator=(const valarray<value_type>& __x) const {

     size_t __idx = 0;

     for (size_t __i = 0; __i < _M_array.size(); ++__i)

       if (_M_mask[__i]) _M_array[__i] = __x[__idx++];

   }

   void operator*=(const valarray<value_type>& __x) const {

     size_t __idx = 0;

     for (size_t __i = 0; __i < _M_array.size(); ++__i)

       if (_M_mask[__i]) _M_array[__i] *= __x[__idx++];

   }

   void operator/=(const valarray<value_type>& __x) const {

     size_t __idx = 0;

     for (size_t __i = 0; __i < _M_array.size(); ++__i)

       if (_M_mask[__i]) _M_array[__i] /= __x[__idx++];

   }

   void operator%=(const valarray<value_type>& __x) const {

     size_t __idx = 0;

     for (size_t __i = 0; __i < _M_array.size(); ++__i)

       if (_M_mask[__i]) _M_array[__i] %= __x[__idx++];

   }

   void operator+=(const valarray<value_type>& __x) const {

     size_t __idx = 0;

     for (size_t __i = 0; __i < _M_array.size(); ++__i)

       if (_M_mask[__i]) _M_array[__i] += __x[__idx++];

   }

   void operator-=(const valarray<value_type>& __x) const {

     size_t __idx = 0;

     for (size_t __i = 0; __i < _M_array.size(); ++__i)

       if (_M_mask[__i]) _M_array[__i] -= __x[__idx++];

   }

   void operator^=(const valarray<value_type>& __x) const {

     size_t __idx = 0;

     for (size_t __i = 0; __i < _M_array.size(); ++__i)

       if (_M_mask[__i]) _M_array[__i] ^= __x[__idx++];

   }

   void operator&=(const valarray<value_type>& __x) const {

     size_t __idx = 0;

     for (size_t __i = 0; __i < _M_array.size(); ++__i)

       if (_M_mask[__i]) _M_array[__i] &= __x[__idx++];

   }

   void operator|=(const valarray<value_type>& __x) const {

     size_t __idx = 0;

     for (size_t __i = 0; __i < _M_array.size(); ++__i)

       if (_M_mask[__i]) _M_array[__i] |= __x[__idx++];

   }

   void operator<<=(const valarray<value_type>& __x) const {

     size_t __idx = 0;

     for (size_t __i = 0; __i < _M_array.size(); ++__i)

       if (_M_mask[__i]) _M_array[__i] <<= __x[__idx++];

   }

   void operator>>=(const valarray<value_type>& __x) const {

     size_t __idx = 0;

     for (size_t __i = 0; __i < _M_array.size(); ++__i)

       if (_M_mask[__i]) _M_array[__i] >>= __x[__idx++];

   }

   void operator=(const value_type& __c) const {

     for (size_t __i = 0; __i < _M_array.size(); ++__i)

       if (_M_mask[__i]) _M_array[__i] = __c;

   }

   ~mask_array() {}

   // Extension: number of true values in the mask

   size_t _M_num_true() const {

     size_t __result = 0;

     for (size_t __i = 0; __i < _M_mask.size(); ++__i)

       if (_M_mask[__i]) ++__result;

     return __result;

   }

 private:

   mask_array(const _Valarray_bool& __mask, valarray<_Tp>& __array)

     : _M_mask(__mask), _M_array(__array)

     {}

   _Valarray_bool _M_mask;

   valarray<_Tp>& _M_array;

 private:                        // Disable assignment

   void operator=(const mask_array<_Tp>&);

 };

 // valarray member functions dealing with mask_array

 template <class _Tp>

 inline valarray<_Tp>::valarray(const mask_array<_Tp>& __x)

   : _Valarray_base<_Tp>(__x._M_num_true())

 {

   typedef typename __type_traits<_Tp>::has_trivial_default_constructor

           _Is_Trivial;

   _M_initialize(_Is_Trivial());

   *this = __x;

 }

 // Behavior is undefined if __x._M_num_true() != this->size()

 template <class _Tp>

 inline valarray<_Tp>& valarray<_Tp>::operator=(const mask_array<_Tp>& __x) {

   size_t __idx = 0;

   for (size_t __i = 0; __i < __x._M_array.size(); ++__i)

     if (__x._M_mask[__i]) (*this)[__idx++] = __x._M_array[__i];

   return *this;

 }

 template <class _Tp>

 inline mask_array<_Tp> valarray<_Tp>::operator[](const _Valarray_bool& __mask)

 {

   return mask_array<_Tp>(__mask, *this);

 }

 //----------------------------------------------------------------------

 // indirect_array

 template <class _Tp>

 class indirect_array {

   friend class valarray<_Tp>;

 public:

   typedef _Tp value_type;

   void operator=(const valarray<value_type>& __x) const {

     for (size_t __i = 0; __i < _M_addr.size(); ++__i)

       _M_array[_M_addr[__i]] = __x[__i];

   }

   void operator*=(const valarray<value_type>& __x) const {

     for (size_t __i = 0; __i < _M_addr.size(); ++__i)

       _M_array[_M_addr[__i]] *= __x[__i];

   }

   void operator/=(const valarray<value_type>& __x) const {

     for (size_t __i = 0; __i < _M_addr.size(); ++__i)

       _M_array[_M_addr[__i]] /= __x[__i];

   }

   void operator%=(const valarray<value_type>& __x) const {

     for (size_t __i = 0; __i < _M_addr.size(); ++__i)

       _M_array[_M_addr[__i]] %= __x[__i];

   }

   void operator+=(const valarray<value_type>& __x) const {

     for (size_t __i = 0; __i < _M_addr.size(); ++__i)

       _M_array[_M_addr[__i]] += __x[__i];

   }

   void operator-=(const valarray<value_type>& __x) const {

     for (size_t __i = 0; __i < _M_addr.size(); ++__i)

       _M_array[_M_addr[__i]] -= __x[__i];

   }

   void operator^=(const valarray<value_type>& __x) const {

     for (size_t __i = 0; __i < _M_addr.size(); ++__i)

       _M_array[_M_addr[__i]] ^= __x[__i];

   }

   void operator&=(const valarray<value_type>& __x) const {

     for (size_t __i = 0; __i < _M_addr.size(); ++__i)

       _M_array[_M_addr[__i]] &= __x[__i];

   }

   void operator|=(const valarray<value_type>& __x) const {

     for (size_t __i = 0; __i < _M_addr.size(); ++__i)

       _M_array[_M_addr[__i]] |= __x[__i];

   }

   void operator<<=(const valarray<value_type>& __x) const {

     for (size_t __i = 0; __i < _M_addr.size(); ++__i)

       _M_array[_M_addr[__i]] <<= __x[__i];

   }

   void operator>>=(const valarray<value_type>& __x) const {

     for (size_t __i = 0; __i < _M_addr.size(); ++__i)

       _M_array[_M_addr[__i]] >>= __x[__i];

   }

   void operator=(const value_type& __c) const {

     for (size_t __i = 0; __i < _M_addr.size(); ++__i)

       _M_array[_M_addr[__i]] = __c;

   }

   ~indirect_array() {}

 private:

   indirect_array(const _Valarray_size_t& __addr, valarray<_Tp>& __array)

     : _M_addr(__addr), _M_array(__array)

     {}

   _Valarray_size_t _M_addr;

   valarray<_Tp>&   _M_array;

 private:                        // Disable assignment

   void operator=(const indirect_array<_Tp>&);

 };

 // valarray member functions dealing with indirect_array

 template <class _Tp>

 inline valarray<_Tp>::valarray(const indirect_array<_Tp>& __x)

   : _Valarray_base<_Tp>(__x._M_addr.size())

 {

   typedef typename __type_traits<_Tp>::has_trivial_default_constructor

           _Is_Trivial;

   _M_initialize(_Is_Trivial());

   *this = __x;

 }

 template <class _Tp>

 inline indirect_array<_Tp>

 valarray<_Tp>::operator[](const _Valarray_size_t& __addr)

 {

   return indirect_array<_Tp>(__addr, *this);

 }

 _STLP_END_NAMESPACE

 # if !defined (_STLP_LINK_TIME_INSTANTIATION)

 #  include <stl/_valarray.c>

 # endif

 #endif /* _STLP_VALARRAY */

 // Local Variables:

 // mode:C++

 // End: