Purpose and learning objectives
L13-L14 · full workflow and independent review. This investigation develops a numerical method and tests its output against a declared benchmark, invariant, uncertainty model, or independent implementation.
- Run a specified scientific workflow from the pinned environment.
- Measure an explicit numerical or statistical diagnostic with units and provenance.
- Separate numerical error from physical model discrepancy and interpret a limitation.
Preparation, setup, and inputs
Software: CPython 3.14.6; dependencies in requirements.txt. From repository root run .venv/Scripts/python.exe materials/ASTR474/src/astr474_computations.py. Then use the corresponding CSV/JSON under materials/ASTR474/data/generated/. Required data: All generated ASTR474 data and source artifacts.
Apparatus: computer with local CPU, terminal, text editor, and browser; no telescope, GPU, network account, or paid service is required. Preserve the generated input files and record file hash/version.
Model scope: The workflow includes level-2 published JPL vector values and clearly identified level-3 synthetic controlled experiments.
Procedure
- Create a clean environment from the pinned requirements and record exact runtime versions.
- Run the shared computation module and compare every generated artifact with its source inputs and seed.
- Choose one numerical experiment; reproduce its key result with a second method or an analytic check.
- Write a claim-evidence table with physical model, numerical error, stochastic uncertainty, parameter uncertainty, and model discrepancy as separate rows.
- Package the code, traceable source records, generated outputs, provenance, command, checksums, and a limitations statement for a peer to rerun.
Measurement record
| Quantity | Value or field | Unit/convention | Source/method |
|---|---|---|---|
| Input configuration | Record solver, version, seed, timestep/grid/tolerance | As defined by the experiment | Command line and source file |
| Primary diagnostic | Record every resolution/sample/fit row, not just the preferred result | State units and normalization | Generated CSV/JSON |
| Independent reference | The final validation dossier retains four distinct measures: three-body energy drift 5.33e-13, shock L1 error 0.00521, transmission standard error 0.00244, and fitted residual RMS 3.0897 m/s. | As stated in the generated example | Analytic/JPL/invariant cross-check |
| Uncertainty/sensitivity | Repeat with changed resolution, seed, parameter, or method | Report interval or relative change | Student analysis |
Analysis and uncertainty
Peer review checks uncertainty categories and whether the claimed precision is supported; reruns are not independent evidence of correctness.
Plot the diagnostic against the controlled parameter; label axes, units, normalization, and reference. Explain any non-monotonic point rather than smoothing or dropping it. If propagating independent errors, state why independence is plausible; preserve correlated/common-mode terms separately.
Deliverables and assessment
- Runnable source or notebook export with command, package versions, and all input/output paths.
- One scientific figure plus a machine-readable table of measurements and convergence/sampling/residual diagnostics.
- A 700-1000 word technical report describing model, method, validation, uncertainty categories, and one failed assumption.
- A short claim-evidence table separating result, numerical check, and domain limitation.
Rubric: 30% correct method and setup; 25% validation and numerical diagnostics; 20% uncertainty/provenance; 15% physical interpretation; 10% clarity and reproducibility. Revisions and resubmissions are encouraged under the syllabus mastery policy.
Data and source provenance
The workflow includes level-2 published JPL vector values and clearly identified level-3 synthetic controlled experiments. Provenance levels, request records, and source verification limits are documented in reference-log.md; generated files and seeds are documented in data/README.md.
References:
- NumPy 2.5 documentation, random Generator
- SciPy 1.18 documentation, solve_ivp
- SciPy 1.18 documentation, least_squares
- Astropy 8.0.1 documentation, units and constants
- REBOUND documentation, WHFast and units
- NASA/JPL Horizons API documentation
- Rein & Liu 2012, REBOUND: An open-source multi-purpose N-body code for collisional dynamics, A&A 537, A128
- Rein & Tamayo 2015, WHFast, MNRAS 452, 376-388