diff --git a/julia/TUG/src/Core/BTCS.jl b/julia/TUG/src/Core/BTCS.jl
index 60320ef..0d80d5e 100644
--- a/julia/TUG/src/Core/BTCS.jl
+++ b/julia/TUG/src/Core/BTCS.jl
@@ -266,7 +266,7 @@ function BTCS_2D(
 
     # Swap alphas, boundary conditions and sx/sy for column-wise calculation
     Threads.@threads for i = 1:cols
-        localB = zeros(T, cols)
+        localB = zeros(T, rows)
         A::Tridiagonal{T} = createCoeffMatrix(
             view(alphaY_t, i, :),
             view(alphaY_t_left, i, :),