klft

A library for lattice field theory simulation accelerated using Kokkos

Installation

use git to clone the repository

git clone https://github.com/aniketsen/klft.git /path/to/klft
cd /path/to/klft

setup kokkos and yaml-cpp

git submodule update --init --recursive

build the library

mkdir /path/to/build
cd /path/to/build

cmake [Kokkos options] /path/to/klft

make -j<number of threads>

Kokkos options

The most important Kokkos options are:

-DKokkos_ENABLE_CUDA=ON to enable CUDA support

-DKokkos_ENABLE_OPENMP=ON to enable OpenMP support

-DKokkos_ARCH_<arch>=ON to enable a specific architecture (e.g. -DKokkos_ARCH_AMPERE80=ON for NVIDIA A100 gpus)

see the Kokkos documentation for more options

Usage

Metropolis

binaries/metropolis
  -f <file_name> --filename <file_name>
     Name of the input file.
     Default: input.yaml
  -h, --help
     Prints this message.
     Hint: use --kokkos-help to see command line options provided by Kokkos.

Example input.yaml

# input.yaml
MetropolisParams:    # parameters for the Metropolis algorithm
  Ndims: 4    # number of dimensions [2,3,4]
  Nd: 4       # number of link dimensions (this must be strictly same as Ndims)
  Nc: 1       # number of colors (defines SU(Nc)) [1,2,3]
  L0: 8       # lattice extent in 0 direction
  L1: 8       # lattice extent in 1 direction
  L2: 8       # lattice extent in 2 direction
  L3: 8       # lattice extent in 3 direction
  nHits: 10       # number of hits per sweep
  nSweep: 1000      # number of sweeps
  seed: 32091     # random seed
  beta: 2.0       # inverse coupling constant
  delta: 0.1      # step size for the Metropolis algorithm

GaugeObservableParams:
  measurement_interval: 10               # interval for measurements
  measure_plaquette: true                # measure the plaquette
  measure_wilson_loop_temporal: true    # measure the temporal Wilson loop
  measure_wilson_loop_mu_nu: true       # measure the spatial Wilson loop
  W_temp_L_T_pairs:      # pairs of (L, T) values for the temporal Wilson loop
    - [2, 2]
    - [3, 4]             # keep a non-decreasing order (as much as possible)
    - [4, 3]             # for maximum efficiency
    - [4, 4]
  W_mu_nu_pairs:      # pairs of (mu, nu) values for the planar Wilson loop
    - [0, 1]
    - [1, 2]
    - [3, 2]
  W_Lmu_Lnu_pairs:      # pairs of (Lmu, Lnu) values for the lengths of the 
    - [2, 2]            # planar Wilson loop in the mu and nu directions
    - [3, 3]            # again, keep a non-decreasing order (as much as possible)
    - [4, 3]
  plaquette_filename: "plaquette.out"  # filename to output the plaquette
  W_temp_filename: "W_temp.out"        # filename to output the temporal Wilson loop
  W_mu_nu_filename: "W_mu_nu.out"      # filename to output the planar Wilson loop
  write_to_file: true                  # write the measurements to file

Environment variables

KLFT_VERBOSITY

Set the verbosity level of the library.

• 0: silent
• 1: summarize
• 2: verbose
• >=3: debug
• Default: 0

KLFT_TUNING

Sets whether to tune the Kokkos MDRangePolicy for rank > 1 or not.

• 0: do not tune
• 1: tune
• Default: 0

KLFT_CACHE_FILE

Sets the file to store the tuning results. Also sets the file to read the tuning results from.

• Default: None