Table Lookup, how to Looking for explanaitiion how to implement an Table lookup


I asked a similar question in an other topic, but i did not get answer I understood, so i tried rephrasing my problem a bit.
the question:
how can i implement an table lookup like in E3 page 138 in the 2.3 cuda programming guide(it is the very end) ?
you would help me best with some code lines

what i want to do is changing the resolution of an image, store in a cudaArray(2D), each pixel is a float4 value. a texture is bound to the array. I think it cant be that hard to use a gpu to change resolution.
just to make some things clear:

  1. i know how to use textures(a bit at least), i read the examples like simple texture and use them alot in my work, i just cant do THAT
  2. i know how to change the resolution the hard way, i am looking for an easy way using textures, as the programming guide suggests it is possible

i am looking forward to your answers.