From 52a39132447d14642e20aac0c79260fde7be7add Mon Sep 17 00:00:00 2001
From: adrianaghiozzi <67669644+adrianaghiozzi@users.noreply.github.com>
Date: Tue, 1 Sep 2026 14:54:38 -0400
Subject: [PATCH 1/2] ForceFreeStates - BUGFIX! - Snap the periodic theta
 endpoint before integrating GGJ geometry

---
 src/ForceFreeStates/Surfaces/Resist.jl     | 4 ++++
 src/ForceFreeStates/Surfaces/ResistEval.jl | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/src/ForceFreeStates/Surfaces/Resist.jl b/src/ForceFreeStates/Surfaces/Resist.jl
index ecfbcd0f8..24a56fc7b 100644
--- a/src/ForceFreeStates/Surfaces/Resist.jl
+++ b/src/ForceFreeStates/Surfaces/Resist.jl
@@ -94,6 +94,10 @@ function resist_eval(sing::SingType, equil::Equilibrium.PlasmaEquilibrium,
         ff[itheta, 6] = dpsisq / bsq
         @views ff[itheta, :] .*= jac / v1
     end
+    # Snap the repeated endpoint exactly equal to the start (see Equilibrium.jl's
+    # GS-residual integrator and issue #240 -- independent spline evaluations at
+    # theta=0/1 can differ by machine epsilon and trip PeriodicBC's check)
+    @views ff[end, :] .= ff[1, :]
     itp = cubic_interp(equil.rzphi_ys, Series(ff); bc=PeriodicBC())
     avg = FastInterpolations.integrate(itp)
 
diff --git a/src/ForceFreeStates/Surfaces/ResistEval.jl b/src/ForceFreeStates/Surfaces/ResistEval.jl
index 04953b6c0..acadf1979 100644
--- a/src/ForceFreeStates/Surfaces/ResistEval.jl
+++ b/src/ForceFreeStates/Surfaces/ResistEval.jl
@@ -165,6 +165,10 @@ function resist_geometry(equil::Equilibrium.PlasmaEquilibrium,
         ff[itheta, 7] = B_here
         @views ff[itheta, :] .*= jac / v1
     end
+    # Snap the repeated endpoint exactly equal to the start (see Equilibrium.jl's
+    # GS-residual integrator and issue #240 -- independent spline evaluations at
+    # theta=0/1 can differ by machine epsilon and trip PeriodicBC's check)
+    @views ff[end, :] .= ff[1, :]
 
     # Integrate each column around θ using the same periodic cubic-spline
     # integrator Mercier.jl uses

From cefa01003f59a0cc34e20b77681428b2efe54788 Mon Sep 17 00:00:00 2001
From: adrianaghiozzi <67669644+adrianaghiozzi@users.noreply.github.com>
Date: Wed, 2 Sep 2026 10:44:01 -0400
Subject: [PATCH 2/2] Shorten overly verbose comments

---
 src/ForceFreeStates/Surfaces/Resist.jl     | 4 +---
 src/ForceFreeStates/Surfaces/ResistEval.jl | 4 +---
 2 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/src/ForceFreeStates/Surfaces/Resist.jl b/src/ForceFreeStates/Surfaces/Resist.jl
index 24a56fc7b..fd4a4b46a 100644
--- a/src/ForceFreeStates/Surfaces/Resist.jl
+++ b/src/ForceFreeStates/Surfaces/Resist.jl
@@ -94,9 +94,7 @@ function resist_eval(sing::SingType, equil::Equilibrium.PlasmaEquilibrium,
         ff[itheta, 6] = dpsisq / bsq
         @views ff[itheta, :] .*= jac / v1
     end
-    # Snap the repeated endpoint exactly equal to the start (see Equilibrium.jl's
-    # GS-residual integrator and issue #240 -- independent spline evaluations at
-    # theta=0/1 can differ by machine epsilon and trip PeriodicBC's check)
+    # Snap the repeated endpoint exactly equal to the start
     @views ff[end, :] .= ff[1, :]
     itp = cubic_interp(equil.rzphi_ys, Series(ff); bc=PeriodicBC())
     avg = FastInterpolations.integrate(itp)
diff --git a/src/ForceFreeStates/Surfaces/ResistEval.jl b/src/ForceFreeStates/Surfaces/ResistEval.jl
index acadf1979..09bd6dd80 100644
--- a/src/ForceFreeStates/Surfaces/ResistEval.jl
+++ b/src/ForceFreeStates/Surfaces/ResistEval.jl
@@ -165,9 +165,7 @@ function resist_geometry(equil::Equilibrium.PlasmaEquilibrium,
         ff[itheta, 7] = B_here
         @views ff[itheta, :] .*= jac / v1
     end
-    # Snap the repeated endpoint exactly equal to the start (see Equilibrium.jl's
-    # GS-residual integrator and issue #240 -- independent spline evaluations at
-    # theta=0/1 can differ by machine epsilon and trip PeriodicBC's check)
+    # Snap the repeated endpoint exactly equal to the start
     @views ff[end, :] .= ff[1, :]
 
     # Integrate each column around θ using the same periodic cubic-spline