FP8 is All You Need (Part 2): Efficient Ozaki-Bailey Style FFT Through Tensor-core Garner Reformulation and Kulisch Escape Route

NVIDIA's Blackwell Ultra (B300) GPU introduces a novel approach to achieving FP64-equivalent throughput for 3-D FFTs by utilizing FP8 tensor cores through the Ozaki-Bailey FFT framework. This method leverages a mantissa-sliced Chinese-remainder reconstruction and integrates Kulisch fixed-point arithmetic to maintain FP64 accuracy while operating on INT32, with projected performance for 1024^3 FFTs at approximately 18 ms. This advancement is significant for practitioners, as it enables efficient utilization of lower-precision computations in memory-bound workloads, paving the way for a dedicated libKulisch library and benchmarking efforts.