, </span><span style=' font-family: monospace;'>subsets</span><span> is the optional number of subsets, </span><span style=' font-family: monospace;'>implementation</span><span> is the used implementation (3, OpenCL, and 4, OpenMP, are supported), </span><span style=' font-family: monospace;'>deviceN</span><span> is the platform used when using implementation 3.</span></div><div  class = 'S1'><span>The alternative way, is to use user-computed detector coordinates. The constructor is then: </span><span style