[us-commits] [ehb54/ultrascan3] 0af114: perceiver: emit psv at the table temperature, not ...

[emre brookes]

  Branch: refs/heads/ehb54-issue-980
  Home:   https://github.com/ehb54/ultrascan3
  Commit: 0af114235e228655fac50e08d209d20d2e66c116
      https://github.com/ehb54/ultrascan3/commit/0af114235e228655fac50e08d209d20d2e66c116
  Author: ehb54 <brookes at uthscsa.edu>
  Date:   2026-08-10 (Mon, 10 Aug 2026)

  Changed paths:
    M us_somo/develop/include/us_hydrodyn_residue_builder.h
    M us_somo/develop/perceiver/tests/builder.cpp
    M us_somo/develop/src/us_hydrodyn_residue_builder.cpp

  Log Message:
  -----------
  perceiver: emit psv at the table temperature, not the increments'

The Durchschlag & Zipper increments describe 25 C. somo.residue is a 20 C
table -- SOMO itself converts with tc_vbar() using 4.25e-4 cm^3 g^-1 K^-1.
The perceiver applied no conversion at all, so every generated entry was
5 K x 4.25e-4 = 0.0021 cm^3/g high: about +0.3%, small enough to read as
method noise and not noise at all.

Found by comparing against Mattia Rocco's independent recalculation. Matching
the temperature reference collapses the disagreement:

    residue        vs his 25 C     vs his 20 C
    GLY ALA VAL    -0.07 .. +0.02%   +0.20 .. +0.33%
    LEU ILE THR
    CYS MET PHE
    TRP ASN GLN
    SER            +0.07%            +0.41%
    ASP            +0.16%            +0.52%

14 of 20 residues agree to within +-0.07% once the reference matches.

His conversion itself is exact, which was the other possibility Mattia raised:
the dv/dT implied by his 25 C and 20 C columns is 4.2500e-04 for all 20
residues with ZERO spread, and equals SOMO's tc_vbar coefficient. No rounding
error there -- the discrepancy was entirely on this side.

The temperatures and the coefficient are Options fields rather than literals,
so a table at another reference temperature is a parameter change.

builder.cpp gains the check: ALA psv 0.7413 at 25 C -> 0.7392 at 20 C, which
is Rocco's tabulated 20 C value exactly. 57 checks, 0 failures.



To unsubscribe from these emails, change your notification settings at https://github.com/ehb54/ultrascan3/settings/notifications