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Feat/compartment fire physics - #15
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Numerics.sln still listed CSharpNumerics.Engines and NumericTest.Engines, which moved to their own repository in e98465b. dotnet build Numerics.sln therefore fails on a clean checkout with MSB3202. That went unnoticed because nothing builds the solution. publish.yml builds and packs Numerics/Numerics/CSharpNumerics.csproj directly, and it runs only on version tags. The same gap has a second consequence worth naming: publish.yml has no dotnet test step at all, so a release can be published to NuGet without a single test having been executed. Locally the suite is blocked by a Windows application control policy that prevents locally built test assemblies from loading, so in practice the tests have not been running anywhere. Removes the two dead project entries and adds a CI workflow that builds the solution and runs the suite on every push and pull request. It does not publish, and publish.yml is left alone - adding a test gate there is a change to the release path and should be a deliberate decision.
Third slice of the shipboard fire work, and the one that replaces guesswork with published correlations. Pure functions in the physics layer, no grid and no simulation state, following RothermelModel. HeatReleaseRate covers t-squared growth with the four standard classes from NFPA 72 and EN 1991-1-2, a full design curve of growth, steady burning and linear decay, and the convective split that plume correlations actually consume. FirePlume is Heskestad: flame height, virtual origin, centreline temperature and velocity, and entrainment. Centreline velocity is the one the Marine buoyancy model needs - it is what turns 'smoke rises' into a rate, and so what the constant-rise stand-in must be replaced by before any timing means anything. Entrainment is why a compartment fills far faster than the fire produces smoke: almost all of the plume mass flow is room air dragged along with it. FractionalEffectiveDose is Purser and ISO 13571: carbon monoxide, hydrogen cyanide, oxygen depletion, and the hyperventilation multiplier by which carbon dioxide makes every other gas worse. It also gives visibility through smoke, which is usually what actually stops escape - ten metres of visibility is lost at soot concentrations where the toxic dose is still negligible. This is what turns the smoke field into a decision variable. A concentration map says where smoke is; a dose says how long someone has, which is the only form an incident commander can act on. Tests check the correlations against their published reduced forms rather than against themselves: the growth coefficients against the four published values, plume temperature and velocity against the standard-air simplifications, and the dose model against known outcomes - 1000 ppm carbon monoxide incapacitating in roughly half an hour, 200 ppm hydrogen cyanide in minutes, five percent carbon dioxide roughly tripling uptake. MQH hot gas layer temperature and a flashover criterion are deliberately left out. Nothing consumes them yet, and building ahead of a consumer is how an API shape ends up wrong.
Numerics.sln still listed CSharpNumerics.Engines and NumericTest.Engines, which moved to their own repository in e98465b. dotnet build Numerics.sln therefore fails on a clean checkout with MSB3202. That went unnoticed because nothing builds the solution. publish.yml builds and packs Numerics/Numerics/CSharpNumerics.csproj directly, and it runs only on version tags. The same gap has a second consequence worth naming: publish.yml has no dotnet test step at all, so a release can be published to NuGet without a single test having been executed. Locally the suite is blocked by a Windows application control policy that prevents locally built test assemblies from loading, so in practice the tests have not been running anywhere. Removes the two dead project entries and adds a CI workflow that builds the solution and runs the suite on every push and pull request. It does not publish, and publish.yml is left alone - adding a test gate there is a change to the release path and should be a deliberate decision.
Two failures that the new CI surfaced. Both predate it; nothing had run the suite before. TestMandelbrot constructs a System.Drawing Bitmap, and System.Drawing.Common is Windows-only from .NET 6 onward, so it can never pass on a Linux runner. It now reports inconclusive off Windows rather than failing. Inconclusive rather than skipped because the test is not irrelevant there - it simply cannot run - and the Mandelbrot mathematics is already covered by the complex number tests beside it. The alternative, moving the whole suite onto a Windows runner for one rendering test, would be a poor trade for a library that otherwise targets netstandard2.1. StratifiedKFoldCrossValidator is a real bug in shipped code, and this commit does not fix it. Folds are filled class by class with each class restarting at fold 0, so a class with fewer members than the fold count leaves later folds short, and small classes throughout leave them empty. An empty fold then reaches the VectorN constructor and fails with 'values cannot be null or empty', which says nothing about the cause. I could not reproduce the root cause by reading: the test generates 100 samples in two balanced classes across five folds, which should give twenty per fold and no empty one. Since the suite cannot be executed locally - a Windows application control policy blocks locally built test assemblies - guessing at a fix for cross-validation code that users are already running would be worse than leaving it visible. So this adds a guard that fails with the sample count, the class count and the smallest class size. The test still fails, deliberately, but the next CI run reports what the fold distribution actually is, which is what is needed to fix it properly.
Root cause of the stratified k-fold failure CI surfaced, and it is worse than the failing test. Series.FromCsv returned Cols as header.Skip(1). The idiom was copied from TimeSeries.FromCsv, where column 0 is the time axis and genuinely is excluded from Data. Series has no time axis, so every name was shifted one step left of the column it described, and IndexOf(Cols, name) pointed at the wrong data column. The stratified test was the loud symptom: its y became a continuous feature instead of the class labels, GroupBy produced a hundred singleton classes, the per-class round-robin put every sample in fold 0, and the empty training set for that fold crashed the VectorN constructor. The quiet symptom matters more. RollingCrossValidator and LeaveOneOutCrossValidator resolve the target through the same lookup, so every cross-validation run on a Series loaded from CSV has been training with the target leaked into the features and validating against a feature column - producing plausible-looking scores. The regression test in the existing suite asserted BestScore > -10, which nonsense results clear comfortably. Cols is now the names of exactly the columns present in Data, in order, whatever was excluded. TimeSeries.FromCsv is untouched: its Skip(1) is correct. The stratified test now excludes the target from X via the same looked-up index instead of a hardcoded one, and a regression test pins the Cols-to-Data alignment directly.
…o end RunBootstrap_SameSeed_ShouldBeReproducible failed in CI with two seeded runs differing by 0.014. The test has always been flaky; it was exposed, not broken, by the recent changes. MonteCarloClustering.Seed seeded the bootstrap sampling and nothing else. The model clone fitted inside each iteration kept its own seed, and the test's KMeans had none - so every centroid initialisation ran off new Random(), which draws a fresh nondeterministic seed per instance. Two identical seeded runs therefore agreed only as long as k-means happened to land in the same local optima both times. On well-separated data that is usually true, which is why the test mostly passed, and 'mostly' is the definition of a flaky test. A seeded run now hands each model clone a seed derived from the run's own generator, through the SetHyperParameters mechanism the models already have. Derived per iteration rather than fixed, so bootstrap replicates keep independent initialisations. Models that take no seed, like DBSCAN, ignore the key. Unseeded runs are untouched. Exact numbers from previously seeded runs will differ, since the generator now also feeds the model seeds. Nothing can have depended on the old values - the model initialisation was nondeterministic, which is the bug.
Third slice of the shipboard fire work, and the one that replaces guesswork with published correlations. Pure functions in the physics layer, no grid and no simulation state, following RothermelModel. HeatReleaseRate covers t-squared growth with the four standard classes from NFPA 72 and EN 1991-1-2, a full design curve of growth, steady burning and linear decay, and the convective split that plume correlations actually consume. FirePlume is Heskestad: flame height, virtual origin, centreline temperature and velocity, and entrainment. Centreline velocity is the one the Marine buoyancy model needs - it is what turns 'smoke rises' into a rate, and so what the constant-rise stand-in must be replaced by before any timing means anything. Entrainment is why a compartment fills far faster than the fire produces smoke: almost all of the plume mass flow is room air dragged along with it. FractionalEffectiveDose is Purser and ISO 13571: carbon monoxide, hydrogen cyanide, oxygen depletion, and the hyperventilation multiplier by which carbon dioxide makes every other gas worse. It also gives visibility through smoke, which is usually what actually stops escape - ten metres of visibility is lost at soot concentrations where the toxic dose is still negligible. This is what turns the smoke field into a decision variable. A concentration map says where smoke is; a dose says how long someone has, which is the only form an incident commander can act on. Tests check the correlations against their published reduced forms rather than against themselves: the growth coefficients against the four published values, plume temperature and velocity against the standard-air simplifications, and the dose model against known outcomes - 1000 ppm carbon monoxide incapacitating in roughly half an hour, 200 ppm hydrogen cyanide in minutes, five percent carbon dioxide roughly tripling uptake. MQH hot gas layer temperature and a flashover criterion are deliberately left out. Nothing consumes them yet, and building ahead of a consumer is how an API shape ends up wrong.
…cklundtransform/CSharpNumerics into feat/compartment-fire-physics
Fourth slice of the shipboard fire work: the mechanism by which fire climbs a ship without any opening. A deck plate over a burning compartment conducts until the space above it is dangerous, smoke or no smoke. HeatSlab resolves transient conduction through the thickness of a plate with convective exchange on both faces, explicit finite differences with internal sub-stepping so a caller may advance by any time step. This is the standard fire-engineering treatment of thin structure - conduction along the plate is ignored, conduction through it is resolved on its own fine grid - and it is deliberately not the 3-D heat solver in the engines: a 10 mm plate has no business being resolved on a 1 m ship grid, and the right tool costs a few nodes per plate cell instead of a volume mesh. Step returns the energy taken from the hot-side gas, so a coupled gas model can remove it and keep the exchange two-way rather than the plate being an infinite sink. Radiation is not modelled, and near flames radiation dominates structure heating, so these results are a floor on heating rate, not a ceiling. The XML docs say so. Tests are against closed-form results, not self-consistency: the steady-state surface temperatures from the series-resistance solution, the lumped-capacitance exponential in the low-Biot limit, and absorbed energy equal to stored energy on an insulated slab. The domain-anchored one: a bare 10 mm steel deck over an 800 K compartment passes a 140 K unexposed-side rise - the A-class criterion - in well under fifteen minutes, which is why A-60 divisions carry insulation.
Purser's correlation for hot-air exposure of a lightly clothed person: about an hour to incapacitation at 40 C, twelve minutes at 100 C. Returns zero at or below 30 C, beneath which the correlation has no validity - ordinary warmth is not a dose. Radiant heat is a separate pathway and is not included. Completes the tenability set for the shipboard work: the smoke solver carries a temperature field, and heat is the dose pathway that field feeds.
CI failed HeatSlab_SteadyState_MatchesSeriesResistance by 2.24 K against a 0.5 K tolerance, and the miss is a confirmation, not a defect: the approach to steady state is exponential with tau = rho*c*L/(h1+h2), about 1170 s here, and 6000 s is 5.15 tau - leaving an analytical residual of exp(-5.15) times the 384 K gap, which is 2.23 K. The solver tracked the closed-form decay to three decimals; the test had not given it time to finish converging inside its own tolerance. Twelve thousand seconds is ten time constants, residual about 0.01 K. The tolerance stays at 0.5 K, doing real work against the discretisation rather than absorbing an unconverged transient. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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