The Template Numerical Toolkit (TNT) is a collection of interfaces and 
reference implementations of numerical objects useful for scientific 
computing in C++. The toolkit defines interfaces for basic data 
structures, such as multidimensional arrays and sparse matrices, commonly 
used in numerical applications. The goal of this package is to provide
reusable software components that address many of the portability and 
maintenance problems with C++ codes.
TNT provides a distinction between "interfaces" and "implementations" of 
TNT components. For example, there is a TNT interface for two-dimensional 
arrays which describes how individual elements are accessed and how 
certain information, such as the array dimensions, can be used in 
algorithms; however, there can be several implementations of such an 
interface: one that uses expression templates, or one that uses BLAS 
kernels, or another that is instrumented to provide debugging 
information. By specifying only the interface, applications codes may 
utilize such algorithms, while giving library developers the greatest 
flexibility in employing optimization or portability strategies. 

WWW:	http://math.nist.gov/tnt/