ИСТИНА

Integral computations for two-electron repulsion energies are very frequently used applications in quantum chemistry. Computational complexity, energy consumption and the size of the output data generated by these computations scales with O(N4), where N is the number of atoms simulated in the system. In many applications, the same integrals are required to be calculated multiple times. Storing these values and reusing them requires impractical amounts of storage space; whereas recalculating them requires a lot of computations. On the other hand, generated data typically requires much less precision than the built-in floating point data types. We propose PaSTRI (Pattern Scaling for Two-electron Repulsion Integrals), a fast novel compression algorithm which makes it possible to calculate these integrals only once, store them, and reuse them at much smaller computational cost then recalculation. PaSTRI is lossy compared to floating point numbers, but still maintains the precision level required by the integral computations. PaSTRI is an extension to SZ compressor package as a part of ECP-EZ. We have evaluated our compressor using GAMESS dataset, and achieved 17.5:1 compression ratio whereas compression ratios for original SZ was 8.0:1 and ZFP[3] was 7.1:1.