More specifically, the pppm/gpu style performs charge assignment and force interpolation calculations on the GPU. These processes are performed either in single or double precision, depending on whether the -DFFT_SINGLE setting was specified in your lo-level Makefile, as discussed above. The FFTs themselves are still calculated on the CPU. If pppm/gpu is used with a GPU-enabled pair style, part of the PPPM calculation can be performed concurrently on the GPU while other calculations for non-bonded and bonded force calculation are performed on the CPU.
J. K. Rowling’s Harry Potter series contains the major theme of good versus evil. Even more important than this, though, is the theme of love. Over the course of the series, Harry Potter learns that he is alive because of his mother’s love, and the sacrifice she made for him. This love, in J. K. Rowling’s conception, is so powerful that it resists the ultimate evil. And, indeed, Lord Voldemort is evil precisely because he is both unable to feel love and unable to grasp its significance. In this quote from the final installment of the series, Dumbledore tells Harry that living without love is the greatest hardship of all.