title: Clamp to edge VS Clamp
body: <p>I am working on an OpenCL project, trying to implement Gaussian filter. At this moment I am stuck at cl_adressing_mode definition, especially I don't get the difference between CL_ADDRESS_CLAMP_TO_EDGE and CL_ADDRESS_CLAMP.</p>
  
  <p>The definition of cl_addressing_mode states: the addressing mode specifies what to do when the coordinate falls outside the range of [0.0, 1.0](for normalized coordinates) or [0,
  dimension - 1](for non-normalized coordinates) but still, doesn't specify what do its parameters do when I apply a convolution matrix to my image input.</p>