From 23bd66eb72144cbbb342029ee0261de559519b6e Mon Sep 17 00:00:00 2001 From: Chris McComb Date: Tue, 13 Oct 2026 03:01:09 -0400 Subject: [PATCH] Document bounded 140 s OSWEC quarter-step audit --- PARITY.md | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/PARITY.md b/PARITY.md index d761f74d..9f5f26fc 100644 --- a/PARITY.md +++ b/PARITY.md @@ -139,7 +139,7 @@ change is `0.00231` rad and PTO work changes by `0.535%`, larger than MATLAB's same-step differences above. A further local Python run at `dt=0.0025` s needs no fallback and gives `0.000953` rad yaw difference and `0.175%` work difference relative to Python `0.005` s. A matching MATLAB -quarter-step source run now passes the paired gates through 120 s; the +quarter-step source run now passes the paired gates through 140 s; the measured result and its longer-window limit are recorded below. A [250 s pinned MATLAB step audit](https://github.com/cmudrc/wec-sim-python/actions/runs/38127365821) @@ -600,11 +600,18 @@ the same quarter-step differs from MATLAB by at most `1.837e-5` rad yaw, `0.008%`. Both comparisons pass the predeclared gates of `0.0006` rad yaw, `0.00015` rad/s speed, `20` N m torque, and `0.1%` work. The two source runs each make 181 heading switches but select different headings at 163 common -samples, beginning at 43.855 s. This establishes a stable, independently -paired early 120 s window. MATLAB's own `0.01`-to-`0.005` s source change -becomes large by 250 s, and a 250 s quarter-step source run remains beyond -the current GitHub job budget. Neither 250 s source convergence nor native -600 s motion parity is established. +samples, beginning at 43.855 s. A [bounded 140 s quarter-step source run](https://github.com/cmudrc/wec-sim-python/actions/runs/38344267558) +passes the same predeclared limits. At 140 s, MATLAB's `0.005`-to-`0.0025` s +self-change is at most `0.0004019` rad yaw, `6.864e-5` rad/s speed, and +`8.236` N m PTO torque, with `0.0762%` relative PTO-work change. Independent +Python at `0.0025` s differs from that quarter-step source by at most +`8.647e-5` rad yaw, `1.507e-5` rad/s speed, `1.808` N m torque, and +`0.020%` relative PTO work. The two MATLAB trajectories each make 225 +heading switches but select different headings at 320 common samples. +This establishes a stable, independently paired early 140 s window. +MATLAB's own `0.01`-to-`0.005` s source change becomes large by 250 s, and a +250 s quarter-step source run remains beyond the current GitHub job budget. +Neither 250 s source convergence nor native 600 s motion parity is established. The [RM3 MoorDyn visualization force export](https://github.com/cmudrc/wec-sim-python/actions/runs/38085085794) records acceleration, excitation, radiation, added mass, restoring, Morison,