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Quickstart

This page demonstrates the fastest fully reproducible workflow to verify that QS³-ED2 builds and runs correctly on your system.

The objective is deliberately minimal:

  • build the code,
  • execute a reference calculation,
  • confirm successful output.

Conceptual background, design philosophy, and citation information are documented on the main documentation home page.

1. Clone and build

git clone https://github.com/QS-Cube/ED2.git
cd ED2
autoreconf -vfi
./configure
make -j

This produces the executable:

source/QS3ED2

The binary is intentionally not installed into PATH. All example scripts resolve it explicitly to avoid environment-dependent failures on HPC systems.

2. Run the smoke test

make check

This executes a minimal reference calculation and verifies basic functionality.

Expected result:

PASS: test_ex1.sh

If this passes, the core solver, BLAS/LAPACK linkage, and OpenMP configuration are working.

3. Run a full example manually

Move to the chain example:

cd script_chain
./run.sh

This performs a small Exact Diagonalization calculation and prints:

  • solver configuration,
  • convergence information,
  • eigenvalues,
  • local magnetization,
  • selected correlation functions.

Output files such as:

eigenvalues.dat
local_mag.dat
two_body_cf_xyz.dat

are generated in the working directory.

Important properties of the example scripts:

  • no recompilation occurs,
  • the executable is resolved explicitly,
  • PATH is never used,
  • helper programs are built at make time only.

These choices ensure reproducible execution on shared HPC environments.

4. Optional: extended regression suite

make check-long

Runs all reference examples sequentially.

Recommended after:

  • moving to a new machine or cluster,
  • changing compiler,
  • changing BLAS / MKL backend.

QS³-ED2 uses OpenMP in the main solver and threaded BLAS/LAPACK libraries. To avoid nested parallelism during validation runs:

export OMP_NUM_THREADS=1
export OPENBLAS_NUM_THREADS=1
export MKL_NUM_THREADS=1

Users may later tune these values for performance benchmarking.