The goal of this tutorial is to explain the background and all necessary steps 
that are required to implement a simple linear algebra operator on the GPU: 
saxpy() as known from the BLAS library. For two vectors x and y of length N 
and a scalar value alpha, we want to compute a scaled vector-vector addition: 
y = y + alpha * x. The saxpy() operation requires almost no background in 
linear algebra, and serves well to illustrate all entry-level GPGPU concepts. 
The techniques and implementation details introduced in this tutorial can 
easily be extended to more complex calculations on GPUs.