MinSSE (pronounced min-ess-ess-ee or min-see, whichever you prefer): A minimal 2/3D Heisenberg lattice simulator using the stochastic series expansion method

Minimal compilation:

clang++ sse_driver.cpp --std=c++17 -Ofast -DNDEBUG -DRANDOM_GENERATOR where RANDOM_GENERATOR can be XORSHIFT128, XORSHIFT32 (don't really recommend this...), SQUARES, AES4, or LCG. You can also replace clang++ with g++ and it should compile.

Not-so-minimal compilation:

clang++ sse_driver.cpp --std=c++17 -Ofast -march=native -mtune=native -g -fno-unroll-loops -malign-double -DNDEBUG -DRANDOM_GENERATOR

The general run signature is:

./a.out nx ny nz beta dilution nbins msteps isteps int32_seed

nx, ny, nz: Lattice sizes along each direction. Periodic boundaries are implemented in all directions. If nz=1, you have a 2D lattice.
beta: Inverse temperature.
dilution: Percentage of vacancies in lattice.
nbins: Number of bins in which to bin the run data.
msteps: Number of Monte-Carlo sweeps per bin. A measurement is done after each sweep.
isteps: Number of equilibriation sweeps. This is to bring the number of operators to an equilibriated number.
int32_seed: An int32 number, which SmallPRNG reads in, mixes a bit, and use that as a seed. It's still all deterministic.

Minimal run with (assuming you're currently in the directory with the a.out executable):

mkdir TestDir
cd TestDir
../a.out 4 6 1 2.0 0.0 100 1000 900 234545234

The above line runs a 4x6x1 lattice at inverse temperature (beta) of 2.0, 0.0 dilution fraction, gathering 100 bins of data, each of 1000 Monte Carlo sweeps. 9000 equilibriation sweeps are carried out prior to taking measurements. The seed used in the initial mixing of the PRNG is 234545234. Note that this is not the seed that your runtime PRNG will use, but is instead a seed that will be given to a smaller PRNG to generate a random integer, which has more state, that is then given to your runtime PRNG.

The above run will output a few files:

spinmask.out: A 'mask' of the spins. 1 corresponds to occupied, 0 to a vacancy.
spinbonds.out: The number of bonds on a spin.
bonds.out: Bonds and the index of the spins it connects.
out.log: Some basic calculation details.
locsusc.dat: The local susceptibility for each spin in the lattice. Each row is a bin.
results.dat: The uniform susceptibility and total energy of the lattice for each bin.

Dependencies:

1. This project uses SmallPRNG as fast and reliable PRNG source.

References:

1. Sandvik, Anders W. "Computational studies of quantum spin systems." AIP Conference Proceedings. Vol. 1297. No. 1. American Institute of Physics, 2010. Section 5. Fehske, Holger, Ralf Schneider, and Alexander Weiße, eds. Computational many-particle physics. Vol. 739. Springer, 2007. Roughly the first half of chapter 10.