Simulation Validator

Goal

Provide a three-stage validation protocol: pre-flight checks, runtime monitoring, and post-flight validation for materials simulations.

Requirements

• Python 3.8+

• No external dependencies (uses Python standard library only)

• Works on Linux, macOS, and Windows

Inputs to Gather

Before running validation scripts, collect from the user:

Input Description Example

Config file Simulation configuration (JSON/YAML) simulation.json

Log file Runtime output log simulation.log

Metrics file Post-run metrics (JSON) results.json

Required params Parameters that must exist dt,dx,kappa

Valid ranges Parameter bounds dt:1e-6:1e-2

Decision Guidance

When to Run Each Stage

Is simulation about to start? ├── YES → Run Stage 1: preflight_checker.py │ └── BLOCK status? → Fix issues, do NOT run simulation │ └── WARN status? → Review warnings, document if accepted │ └── PASS status? → Proceed to run simulation │ Is simulation running? ├── YES → Run Stage 2: runtime_monitor.py (periodically) │ └── Alerts? → Consider stopping, check parameters │ Has simulation finished? ├── YES → Run Stage 3: result_validator.py │ └── Failed checks? → Do NOT use results │ → Run failure_diagnoser.py │ └── All passed? → Results are valid

Choosing Validation Thresholds

Metric Conservative Standard Relaxed

Mass tolerance 1e-6 1e-3 1e-2

Residual growth 2x 10x 100x

dt reduction 10x 100x 1000x

Script Outputs (JSON Fields)

Script Output Fields

scripts/preflight_checker.py

report.status , report.blockers , report.warnings

scripts/runtime_monitor.py

alerts , residual_stats , dt_stats

scripts/result_validator.py

checks , confidence_score , failed_checks

scripts/failure_diagnoser.py

probable_causes , recommended_fixes

Three-Stage Validation Protocol

Stage 1: Pre-flight (Before Simulation)

• Run scripts/preflight_checker.py --config simulation.json

• BLOCK status: Stop immediately, fix all blocker issues

• WARN status: Review warnings, document accepted risks

• PASS status: Proceed to simulation

python3 scripts/preflight_checker.py
--config simulation.json
--required dt,dx,kappa
--ranges "dt:1e-6:1e-2,dx:1e-4:1e-1"
--min-free-gb 1.0
--json

Stage 2: Runtime (During Simulation)

• Run scripts/runtime_monitor.py --log simulation.log periodically

• Configure alert thresholds based on problem type

• Stop simulation if critical alerts appear

python3 scripts/runtime_monitor.py
--log simulation.log
--residual-growth 10.0
--dt-drop 100.0
--json

Stage 3: Post-flight (After Simulation)

• Run scripts/result_validator.py --metrics results.json

• All checks PASS: Results are valid for analysis

• Any check FAIL: Do NOT use results, diagnose failure

python3 scripts/result_validator.py
--metrics results.json
--bound-min 0.0
--bound-max 1.0
--mass-tol 1e-3
--json

Failure Diagnosis

When validation fails:

python3 scripts/failure_diagnoser.py --log simulation.log --json

Conversational Workflow Example

User: My phase field simulation crashed after 1000 steps. Can you help me figure out why?

Agent workflow:

• First, check the log for obvious errors: python3 scripts/failure_diagnoser.py --log simulation.log --json

• If diagnosis suggests numerical blow-up, check runtime stats: python3 scripts/runtime_monitor.py --log simulation.log --json

• Recommend fixes based on findings:

• If residual grew rapidly → reduce time step

• If dt collapsed → check stability conditions

• If NaN detected → check initial conditions

Error Handling

Error Cause Resolution

Config not found

File path invalid Verify config path exists

Non-numeric value

Parameter is not a number Fix config file format

out of range

Parameter outside bounds Adjust parameter or bounds

Output directory not writable

Permission issue Check directory permissions

Insufficient disk space

Disk nearly full Free up space or reduce output

Interpretation Guidance

Status Meanings

Status Meaning Action

PASS All checks passed Proceed with confidence

WARN Non-critical issues found Review and document

BLOCK Critical issues found Must fix before proceeding

Confidence Score Interpretation

Score Meaning

1.0 All validation checks passed

0.75+ Most checks passed, minor issues

0.5-0.75 Significant issues, review carefully

< 0.5 Major problems, do not trust results

Common Failure Patterns

Pattern in Log Likely Cause Recommended Fix

NaN, Inf, overflow Numerical instability Reduce dt, increase damping

max iterations, did not converge Solver failure Tune preconditioner, tolerances

out of memory Memory exhaustion Reduce mesh, enable out-of-core

dt reduced Adaptive stepping triggered May be okay if controlled

Limitations

• Not a real-time monitor: Scripts analyze logs after-the-fact

• Regex-based: Log parsing depends on pattern matching; may miss unusual formats

• No automatic fixes: Scripts diagnose but don't modify simulations

References

• references/validation_protocol.md

• Detailed checklist and criteria

• references/log_patterns.md

• Common failure signatures and regex patterns

Version History

• v1.1.0 (2024-12-24): Enhanced documentation, decision guidance, Windows compatibility

• v1.0.0: Initial release with 4 validation scripts