verify-implementation

Validates Python implementations of textbook fluid mechanics equations using a seven-level evidence ladder.

Updated Sep 13, 2026
One-click install
npx skills add https://github.com/shammun/fluidpy --skill verify-implementation-shammun
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: verify-implementation
Source: https://github.com/shammun/fluidpy/tree/main/.claude/skills/verify-implementation
Command: npx skills add https://github.com/shammun/fluidpy --skill verify-implementation-shammun

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill requires numpy, scipy, sympy, pytest, pint.

What problem does it solve? When translating equations from a textbook into Python code there is no reference implementation to diff against, so correctness must be proven by making the mathematics test itself. This Skill defines how to build that proof for every chapter of a fluid mechanics learning project. ## Core Features & Use Cases - V1–V7 evidence ladder: analytic exact solutions, sympy symbolic re-derivation and dimensional checks, convergence/order-of-accuracy studies, conservation-law residuals, cited published benchmarks, book-printed values, and limit/symmetry/invariance checks. - Tiered evidence requirements: CORE items need at least two independent evidence levels, NOTE items at least one, and every notebook-facing function at least a smoke test with a physical sanity assertion. - Ready-made assets: default tolerance table, a pytest test-file skeleton, a benchmark catalogue (Blasius, lid-driven cavity, Sod shock tube, Rayleigh–Bénard), a verification report format, and a structured failure loop with the most common physics-coding bug hypotheses. - Use Case: After implementing the Blasius boundary-layer solver for Chapter 9, use this Skill to write tests that check the wall shear against Howarth's 0.332057 benchmark, verify the ODE residual symbolically, and confirm the far-field limit — then produce the chapter verification report. ## Quick Start Ask the assistant to verify the chapter implementation using the verify-implementation evidence ladder and produce the verification report.

Frequently Asked Questions about verify-implementation

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I verify scientific Python code with no reference implementation?

Use independent evidence levels that test the mathematics itself: compare against exact analytic solutions, re-derive equations symbolically with sympy, measure convergence order on refined grids, and assert conservation-law residuals. At least two independent levels are required so one bug cannot fool both checks.

How do I test the order of accuracy of a numerical scheme?

Compute errors at grid spacings h, h/2, and h/4 against an exact or manufactured solution, then take the least-squares slope of log error versus log h. The observed order must fall within ±0.15 of the design order, and stability limits like CFL numbers should also be asserted.

What benchmarks exist for validating fluid dynamics solvers?

Standard cited benchmarks include Blasius wall shear f''(0) = 0.332057, Ghia's lid-driven cavity profiles at Re 100–1000, the Sod shock tube, Rayleigh–Bénard critical Rayleigh number 1707.762, and plane Poiseuille stability at Re 5772.22. Each value must be verified against its cited source before use.

Why do fluid mechanics code tests usually fail?

Most failures come from sign conventions, missing factors of 2 or one-half, confusing kinematic and dynamic viscosity, wrong reference lengths in Reynolds numbers, boundary conditions applied at nodes instead of faces, and degrees-versus-radians errors. Check the test itself first, then the code, for at most three rounds.

Can textbook example values go into public test files?

No. Book-derived worked-example values stay in a private, git-ignored JSON file and the tests are skipped when it is absent. Public tests use their own inputs with analytic formulas, and reports may only state the percentage agreement, not the book's table itself.