By: Kaapo Seppänen <seppanenkaapo@gmail.com>
register thermal bodies per contour offset and test tail precision Thermal function-map entries took the contour offset s as a runtime argument. Evaluator optimization could then group (1 + s)/2 + n so that the vacuum weight met an exponentially small occupation before s, and the generic evaluator lost the gluon tail: 2e-8 relative error at a = 10 and an exact zero at a = 40. Each body is now registered once per offset, with s as a tag. The vacuum weight folds symbolically, and the s = -1 body is the bare occupation, independent of evaluation order. Regression tests cover the precision fixes at both temperatures: - zero_temperature_steps_are_exact_outside_the_fermi_sea requires the order-zero body to equal its vacuum weight exactly above the Fermi surface, in real and complex f64, compiled C++ and Arb. A step written as theta(E - sigma*mu) fails on about a fifth of the sampled energies. - vacuum_subtracted_thermal_weights_keep_uv_tails_and_exact_zeros evaluates vacuum-subtracted weights with a nonzero vacuum value through the production evaluator. Eager f64, symjit and Quad must match an Arb oracle from the bulk to occupations near binary64 underflow, and zero temperature must give exact zeros outside the Fermi sea. - thermal_sunrise_f64_keeps_uv_tails_and_exact_zeros generates the quark sunrise with UV subtraction and the assembly backend. Raw f64 must match Arb along a UV ray at finite temperature and vanish exactly at zero temperature and density. Reverting the hyperbolic bodies, the numerical vacuum subtraction, the zero-temperature step or the tagged offset each fails at least one test. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>