Comment puis-je utiliser un STD :: Valarray pour stocker / manipuler un tableau 2D contigu?

#include <iostream>
#include <valarray>

using namespace std;

typedef valarray<valarray<int> > va2d;

int main()
{
    int data[][3] = { {1, 2, 3}, {4, 5, 6} };
    va2d mat(valarray<int>(3), 2);
    for (int i = 0; i < 2; ++i)
    {
        for (int j = 0; j < 3; ++j)
           mat[ i ][ j ] = data[ i ][ j ];
    }
    for (int i = 0; i < 2; ++i)
        for (int j = 0; j < 3; ++j)
           cout << mat[ i ][ j ] << endl;
}
More on valarray:
It is optimized for numeric computation.
It is a vector like container with special member functions for slicing and dicing.
No iterators
Designed for vector machines and perform poorly on current ones: vector access may be faster
Was not supported by all compilers (check the documentation)  / poorly implemented
See 26.1 for the types that can be used as a parameter to valarray<T>: E.g:

  3 In addition, many member and related
  functions of valarray can be
  successfully instantiated and will
  exhibit well-defined behavior if and
  only if T satisfies additional
  requirements specified for each such
  member or related function. 
  
  4 [
  Example: It is valid to instantiate
  valarray, but operator>()
  will not be successfully instantiated
  for valarray operands, since
  complex does not have any ordering
  operators. —end example ]
Edit#2: The standard gurantees that vector, like arrays, always use contiguous memory. Also, we have:
  26.5.2 Class template valarray
  
  1 The class template valarray is a
  one-dimensional smart array, with
  elements numbered sequentially from
  zero. It is a representation of the
  mathematical concept of an ordered set
  of values. The illusion of higher
  dimensionality may be produced by the
  familiar idiom of computed indices,
  together with the powerful
  subsetting capabilities provided by
  the generalized subscript operators.
and further:
  26.5.2.3 valarray element access
  
  4 Likewise, the expression &a[i] !=
  &b[j] evaluates as true for any two
  arrays a and b and for any size_t i
  and size_t j such that i is less than
  the length of a and j is less than the
  length of b. This property indicates
  an absence of aliasing and may be used
  to advantage by optimizing compilers.