Arena Allocator
The Arena is GradCore-Tensor's memory backbone. If you've ever watched a neural network training session grind to a halt because malloc decided it was a great time to coalesce free blocks, you'll appreciate what an arena allocator does for you: it doesn't bother with any of that.
Platform Layer
platform.hpp is a thin wrapper around OS-level operations: virtual memory management and entropy generation. All the gritty mmap/munmap/mprotect calls live here so the rest of the codebase stays clean and portable (in theory — in practice it's Linux only, as the Introduction honestly admits).
PRNG
GradCore-Tensor uses a PCG (Permuted Congruential Generator) for all random number generation. PCG is fast, has excellent statistical properties, and produces 32 bits of randomness per step — which is exactly what you need for weight initialisation and data shuffling, and absolutely overkill for anything that doesn't need cryptographic security (which is everything in a neural network training loop).