From b1fe3597607d70714e4f575fa14fe848532d8d4b Mon Sep 17 00:00:00 2001 From: Emily Boudreaux Date: Sat, 19 Sep 2026 13:05:53 -0400 Subject: [PATCH] Document stellar support contract for log density --- experiments/LOG_DENSITY_ASSESSMENT_2026-09-19.md | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/experiments/LOG_DENSITY_ASSESSMENT_2026-09-19.md b/experiments/LOG_DENSITY_ASSESSMENT_2026-09-19.md index 0ca9ad4..7957f1e 100644 --- a/experiments/LOG_DENSITY_ASSESSMENT_2026-09-19.md +++ b/experiments/LOG_DENSITY_ASSESSMENT_2026-09-19.md @@ -288,6 +288,15 @@ The same representation must feed gravity source/force, centrifugal force, mass, angular momentum, diagnostics and exported profiles. Their dependency generation, quadrature, cache invalidation and normalization must agree. +The implementation must preserve density's stellar-only support. Physical +density and its directional action must remain identically zero in exterior +and vacuum domains; the positive reconstruction applies only in the material +domain. An inactive log coefficient stored as zero must not be exponentiated +into `rho_scale` outside the star. Domain support must therefore be part of the +representation contract shared by operators, diagnostics and exports. This +intentional exterior vacuum is distinct from underflow inside the material and +from the intended zero trace of a vanishing reference factor at its boundary. + The current registry represents density as an independent scalar L2 field, and the prepared source and force operators read it as a polynomial grid function. The current field relationship catalog supports independent and differential @@ -299,9 +308,9 @@ contracts are in `field_registry.cppm`, `field_base.cppm`, `normalization/stellar_equilibrium.cppm`, and `preconditioning/material_surface.cppm`. -For the currently intended exact-vacuum polytrope, continue the separately -authorized density-only order study first. Its cost and pointwise-error results -provide the right baseline. If log density remains attractive, the next bounded +For the currently intended exact-vacuum polytrope, the companion density-only +order study supplies the polynomial baseline, including cost and pointwise +error. If log density remains attractive, the next bounded question is whether a physically justified vanishing reference can provide a regular independent coordinate without importing a restrictive EOS assumption. For a genuinely finite-density outer boundary, raw pointwise log density is a