name	simulation-validator
description	Validate simulations before, during, and after execution. Use for pre-flight checks, runtime monitoring, post-run validation, diagnosing failed simulations, checking convergence, detecting NaN/Inf, or verifying mass/energy conservation.
allowed-tools	Read, Bash, Write, Grep, Glob

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

simulation-validator

Install Skill

SKILL.md