Large params consume huge amounts of memory

[crockeea]

Following up on #84:
I've set SEAL_POLY_MOD_DEGREE_MAX to 262144 and SEAL_COEFF_MOD_COUNT_MAX to 122 in defines.h, and updated the primes in globals.cpp per #84. Now I'm getting a "bad_alloc" in MemoryPoolHeadMT::get().

I'm on an instance with 64GB of memory, and watched SEALContext creation happily eat right though that (via free -hm), followed by the out-of-memory error.

64GB seems pretty excessive; is this expected? How much memory should I need for these parameters?

[kimlaine]

Well, a single polynomial will now be 244 MB in memory. When you create your SEALContext, maybe it's best if you don't create the modulus switching chain: auto context = SEALContext::Create(parms, false);.