dqmc-run

name	dqmc-run
description	Execute DQMC Monte Carlo sweeps on HDF5 simulation files. Use when running simulations, checkpointing long runs, using the queue system for multiple files, or checking simulation status.

Run Simulations

Inputs

• HDF5 simulation file(s) from the dqmc-generate and dqmc-parameter-scans skills
• Binary at build/dqmc, worker utility from dqmc-util worker

Outputs

• Updated HDF5 files with measurements in /meas_eqlt/ (and /meas_uneqlt/ if enabled)

Decision Rules (single vs queue)

• Exactly 1 file: run it directly with build/dqmc sim_0.h5.
• 2+ files: use the queue/worker system (dqmc-util enqueue + dqmc-util worker) even on a local workstation.
  • This avoids ad-hoc shell loops, makes restarts/checkpointing consistent, and scales to parallel execution safely.

Procedure

Single file:

build/dqmc sim_0.h5

With checkpointing (long runs):

build/dqmc -s 300 -t 3600 sim_0.h5  # checkpoint every 300 seconds, max runtime 3600 seconds

Multiple files (queue system):

# 1. Add files to queue/ (globs are expanded by Python, so quote them)
dqmc-util enqueue queue 'data/run/bin_*.h5'

# 2. Start workers
dqmc-util worker queue ./build/dqmc -n 8 -s 300 -t 3600  # 8 parallel workers

Multiple files (local temperature scan example):

# enqueue all bins across temperatures
dqmc-util enqueue queue 'runs/pi_pi_U8_6x6/T*/bin_*.h5'

# run N workers in parallel (pick N for your machine)
dqmc-util worker queue ./build/dqmc -n 8 -s 300 -t 3600

Validation (single file)

dqmc-util summary sim_0.h5

For multiple files:

dqmc-util print-n data/run/   # directory paths should end with '/'

Failure Modes

Symptom	Cause	Recovery
"opening... failed"	File doesn't exist	Check path
NaN in output	Numerical instability	Reduce dt and/or n_matmul. Check parameters
Killed by scheduler	Exceeded time limit	Use -t flag, checkpoint enabled
Large errorbars	Sign problem	Add more sweeps and/or bins

Do Not

• Kill running simulations without checkpointing (-s flag)
• Run multiple workers on the same file
• Use manual shell loops for 2+ files (prefer dqmc-util enqueue + dqmc-util worker)