Data structure memory layout. (A) An example data structure containing three variables to hold 3D spatial coordinates. (B) Memory layout of the variables when N data structures are allocated together in a CPU program. The variables for each data structure are grouped together in sequential memory locations. (C) Preferable memory layout of N data structures for a GPU program. Each variable in the data structure are grouped together in sequential memory locations, and each variable group is padded to value A to insure alignment requirements. Alignment can be handled automatically, such as with CUDA's cudaMallocPitch function, and the alignment value must be used when calculating array indexes.