From f34010346938bfcd246fbf3b78d146201040f275 Mon Sep 17 00:00:00 2001
From: juddmehr <juddmehr@gmail.com>
Date: Mon, 24 Feb 2025 15:33:39 -0700
Subject: [PATCH] add options for preconditioning elliptic grid

---
 src/preprocess/geometry/wake_geometry.jl | 86 ++++++++++++------------
 src/utilities/options.jl                 |  5 ++
 2 files changed, 48 insertions(+), 43 deletions(-)

diff --git a/src/preprocess/geometry/wake_geometry.jl b/src/preprocess/geometry/wake_geometry.jl
index fb02e41..d15afaf 100644
--- a/src/preprocess/geometry/wake_geometry.jl
+++ b/src/preprocess/geometry/wake_geometry.jl
@@ -368,56 +368,56 @@ function relax_grid!(
     tabchar="    ",
     ntab=1,
 )
-
-    # if verbose
-    #     println(tabchar^ntab * "Preconditioning Elliptic Grid System using SLOR")
-    # end
-    # # - Relax grid to allow Newton solve a tractable starting point - #
-    # relax_grid!(
-    #     wake_grid;
-    #     iteration_limit=grid_solver_options.iteration_limit,
-    #     atol=grid_solver_options.atol,
-    #     converged=grid_solver_options.converged,
-    #     verbose=verbose,
-    #     tabchar="\t",
-    #     ntab=1,
-    # )
+    if grid_solver_options.precondition
+        if verbose
+            println(tabchar^ntab * "Preconditioning Elliptic Grid System using SLOR")
+        end
+        # - Relax grid to allow Newton solve a tractable starting point - #
+        relax_grid!(
+            wake_grid;
+            iteration_limit=grid_solver_options.iteration_limit,
+            atol=grid_solver_options.atol,
+            converged=grid_solver_options.converged,
+            verbose=verbose,
+            tabchar="\t",
+            ntab=1,
+        )
+    end
 
     # - Converge grid with NLsolve - #
 
-    # reset convergence flag
-    grid_solver_options.converged[1] = false
+    if !grid_solver_options.converged[1]
 
-    if verbose
-        println(
-            tabchar^ntab *
-            "Solving Elliptic Grid System using $(grid_solver_options.algorithm) Method",
+        # reset convergence flag
+        grid_solver_options.converged[1] = false
+
+        if verbose
+            println(
+                tabchar^ntab *
+                "Solving Elliptic Grid System using $(grid_solver_options.algorithm) Method",
+            )
+        end
+
+        # solve
+        solve_elliptic_grid!(
+            wake_grid;
+            algorithm=grid_solver_options.algorithm,
+            atol=grid_solver_options.atol,
+            iteration_limit=grid_solver_options.iteration_limit,
+            grid_solver_options.converged,
+            grid_solver_options.residual_value,
+            grid_solver_options.iterations,
+            verbose=verbose,
         )
+    else
+        if verbose
+            println(
+                tabchar^ntab *
+                "Preconditioning Elliptic Grid System converged within final tolerance, skipping non-linear solve.",
+            )
+        end
     end
 
-    # # precondition
-    # relax_grid!(
-    #     wake_grid;
-    #     iteration_limit=grid_solver_options.iteration_limit,
-    #     atol=grid_solver_options.atol,
-    #     converged=grid_solver_options.converged,
-    #     verbose=verbose,
-    #     tabchar="\t",
-    #     ntab=1,
-    # )
-
-    # solve
-    solve_elliptic_grid!(
-        wake_grid;
-        algorithm=grid_solver_options.algorithm,
-        atol=grid_solver_options.atol,
-        iteration_limit=grid_solver_options.iteration_limit,
-        grid_solver_options.converged,
-        grid_solver_options.residual_value,
-        grid_solver_options.iterations,
-        verbose=verbose,
-    )
-
     return wake_grid
 end
 
diff --git a/src/utilities/options.jl b/src/utilities/options.jl
index 352d851..24f5b4f 100644
--- a/src/utilities/options.jl
+++ b/src/utilities/options.jl
@@ -652,14 +652,19 @@ Options for Newton elliptic grid solver.
 - `atol::Float = 3e-10` : absolute convergence tolerance
 - `algorithm::Symbol = :newton` : algorithm to use in NLsolve.jl
 - `autodiff::Symbol = :forward` : differentiation method to use in NLsolve.jl
+- `precondition = false` : flag to precondition with SLOR
+- `precondition_max_iterations = 3` : number of precondition iterations
 - `converged::AbstractArray{Bool}` = [false]
 - `iterations::AbstractArray{Int} = [0]` : iteration counter
+- `residual_value::AbstractArray{Int} = [0]` : residual value
 """
 @kwdef struct GridSolverOptions{TB,TF,TI,TSym} <: GridSolverOptionsType
     iteration_limit::TI = 30
     atol::TF = 3e-10
     algorithm::TSym = :newton
     autodiff::TSym = :forward
+    precondition::TB = false
+    precondition_max_iterations::TI = 3
     converged::AbstractArray{TB} = [false]
     iterations::AbstractArray{TI} = [0]
     residual_value::AbstractArray{TF} = [0.0]