From a5fc5d688590317cc3ca9cd6efe231464cbf71fc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jorge=20P=C3=A9rez=20Zerpa?=
 <42485529+jorgepz@users.noreply.github.com>
Date: Sat, 10 Dec 2022 00:47:59 -0300
Subject: [PATCH] add missing docstring for Free BC (#530)

---
 src/Interpolations.jl | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/Interpolations.jl b/src/Interpolations.jl
index b742175a..4857215c 100644
--- a/src/Interpolations.jl
+++ b/src/Interpolations.jl
@@ -94,6 +94,7 @@ struct Throw{GT<:Union{GridType,Nothing}} <: BoundaryCondition gt::GT end
 struct Flat{GT<:Union{GridType,Nothing}} <: BoundaryCondition gt::GT end
 "`Line(gt)` uses a constant slope for extrapolation"
 struct Line{GT<:Union{GridType,Nothing}} <: BoundaryCondition gt::GT end
+"`Free(gt)` the free boundary condition makes sure the interpoland has a continuous third derivative at the second-to-outermost cell boundary"
 struct Free{GT<:Union{GridType,Nothing}} <: BoundaryCondition gt::GT end
 "`Periodic(gt)` applies periodic boundary conditions"
 struct Periodic{GT<:Union{GridType,Nothing}} <: BoundaryCondition gt::GT end