From 97e318ff5d90c165c3b2df2cb2c360d98b52b16a Mon Sep 17 00:00:00 2001
From: nebmit <76664673+nebmit@users.noreply.github.com>
Date: Thu, 30 Nov 2023 15:09:39 +0100
Subject: [PATCH] perf: added threading

[skip ci]
---
 julia/tug/Core/FTCS.jl | 23 ++++++++++-------------
 1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/julia/tug/Core/FTCS.jl b/julia/tug/Core/FTCS.jl
index 8db17be..87d9fd5 100644
--- a/julia/tug/Core/FTCS.jl
+++ b/julia/tug/Core/FTCS.jl
@@ -157,10 +157,10 @@ end
 
 function FTCS_1D(grid::Grid{T}, bc::Boundary{T}, timestep::T) where {T}
     colMax = getCols(grid)
-    sx = timestep / getDeltaCol(grid) * getDeltaCol(grid)
+    sx = timestep / (getDeltaCol(grid)^2)
 
-    # matrix for concentrations at time t+1
-    concentrations_t1 = zeros(1, colMax)
+    concentrations = getConcentrations(grid)
+    concentrations_t1 = copy(concentrations)
 
     # only one row in 1D case -> row constant at index 1
     row = 1
@@ -168,17 +168,14 @@ function FTCS_1D(grid::Grid{T}, bc::Boundary{T}, timestep::T) where {T}
     # inner cells
     # independent of boundary condition type
     for col = 2:colMax-1
-        concentrations_t1[row, col] = getConcentrations(grid)[row, col] +
-                                      sx * calcHorizontalChange(grid, row, col)
+        concentrations_t1[row, col] += sx * calcHorizontalChange(grid, row, col)
     end
 
     # left boundary; hold column constant at index 1
-    concentrations_t1[row, 1] = getConcentrations(grid)[row, 1] +
-                                sx * calcHorizontalChangeLeftBoundary(grid, bc, row, 1)
+    concentrations_t1[row, 1] += sx * calcHorizontalChangeLeftBoundary(grid, bc, row, 1)
 
     # right boundary; hold column constant at max index
-    concentrations_t1[row, colMax] = getConcentrations(grid)[row, colMax] +
-                                     sx * calcHorizontalChangeRightBoundary(grid, bc, row, colMax)
+    concentrations_t1[row, colMax] += sx * calcHorizontalChangeRightBoundary(grid, bc, row, colMax)
 
     # overwrite obsolete concentrations
     setConcentrations!(grid, concentrations_t1)
@@ -193,9 +190,7 @@ function FTCS_2D(grid::Grid{T}, bc::Boundary{T}, timestep::T) where {T}
     concentrations = getConcentrations(grid)
     concentrations_t1 = copy(concentrations)
 
-    # inner cells
-    # these are independent of the boundary condition type
-    for row = 2:rowMax-1
+    Threads.@threads for row = 2:rowMax-1
         # inner cells
         for col = 2:colMax-1
             concentrations_t1[row, col] += sy * calcVerticalChange(grid, row, col) +
@@ -205,16 +200,18 @@ function FTCS_2D(grid::Grid{T}, bc::Boundary{T}, timestep::T) where {T}
         # left boundary without corners
         concentrations_t1[row, 1] += sx * calcHorizontalChangeLeftBoundary(grid, bc, row, 1) +
                                      sy * calcVerticalChange(grid, row, 1)
+
         # right boundary without corners
         concentrations_t1[row, colMax] += sx * calcHorizontalChangeRightBoundary(grid, bc, row, colMax) +
                                           sy * calcVerticalChange(grid, row, colMax)
     end
 
     # top / bottom without corners / looping over columns
-    for col = 2:colMax-1
+    Threads.@threads for col = 2:colMax-1
         # top
         concentrations_t1[1, col] += sy * calcVerticalChangeTopBoundary(grid, bc, 1, col) +
                                      sx * calcHorizontalChange(grid, 1, col)
+
         # bottom
         concentrations_t1[rowMax, col] += sy * calcVerticalChangeBottomBoundary(grid, bc, rowMax, col) +
                                           sx * calcHorizontalChange(grid, rowMax, col)