Very big matrix multiplication in FPGA
This looks like a case of premature optimization. Start by implementing your algorithm iteratively, and see how fast it performs. Then you'll know exactly how much faster you need to make it, and decide how much operations (and which ones) you will do in parallel.

Implementing the whole thing as a 1-step combinatorial function will not work well: it will require a ton of resources and won't even run that fast without proper pipelining.