From 30816fb1931f8ea3a70215daf77636eb425cc91a Mon Sep 17 00:00:00 2001
From: Anton Khirnov <anton@khirnov.net>
Date: Fri, 28 Dec 2018 13:09:13 +0100
Subject: Make more solver parameters runtime-configurable.

---
 param.ccl                    | 30 ++++++++++++++++++++++++++++++
 src/maximal_slicing_axi_mg.c | 28 ++++++++++++++++++++++------
 2 files changed, 52 insertions(+), 6 deletions(-)

diff --git a/param.ccl b/param.ccl
index 0795ac4..204a942 100644
--- a/param.ccl
+++ b/param.ccl
@@ -13,6 +13,36 @@ CCTK_INT fd_stencil "finite differencing stencil"
     1: :: ""
 } 1
 
+RESTRICTED:
+CCTK_INT maxiter "maximum number of solver iterations"
+{
+    1: :: ""
+} 64
+
+RESTRICTED:
+CCTK_INT nb_cycles "number of coarse-correction cycles per level"
+{
+    1: :: ""
+} 1
+
+RESTRICTED:
+CCTK_INT nb_relax_pre "number of relaxation steps before coarse-grid correction"
+{
+    0: :: ""
+} 2
+
+RESTRICTED:
+CCTK_INT nb_relax_post "number of relaxation steps after coarse-grid correction"
+{
+    0: :: ""
+} 2
+
+RESTRICTED:
+CCTK_REAL tol_residual "maximum absolute value of the residual"
+{
+    0: :: ""
+} 1e-12
+
 RESTRICTED:
 CCTK_INT stats_every "print elliptic solver stats every <count> coarsest-level steps"
 {
diff --git a/src/maximal_slicing_axi_mg.c b/src/maximal_slicing_axi_mg.c
index 0fe9a54..93130d7 100644
--- a/src/maximal_slicing_axi_mg.c
+++ b/src/maximal_slicing_axi_mg.c
@@ -78,6 +78,11 @@ typedef struct MSMGContext {
     cGH *gh;
 
     int fd_stencil;
+    int maxiter;
+    int nb_cycles;
+    int nb_relax_post;
+    int nb_relax_pre;
+    double tol_residual;
 
     CoordPatch *patches;
     int nb_patches;
@@ -236,9 +241,11 @@ static CoordPatch *get_coord_patch(MSMGContext *ms, int level)
     cp->solver->boundaries[MG2D_BOUNDARY_0U]->type = MG2D_BC_TYPE_FIXVAL;
     cp->solver->boundaries[MG2D_BOUNDARY_1U]->type = MG2D_BC_TYPE_FIXVAL;
 
-    cp->solver->maxiter   = 32;
-    cp->solver->tol       = 1e-10;
-    cp->solver->nb_cycles = 2;
+    cp->solver->maxiter   = ms->maxiter;
+    cp->solver->tol       = ms->tol_residual;
+    cp->solver->nb_cycles = ms->nb_cycles;
+    cp->solver->nb_relax_post = ms->nb_relax_post;
+    cp->solver->nb_relax_pre  = ms->nb_relax_pre;
 
     cp->solver->opaque       = ms;
     cp->solver->log_callback = log_callback;
@@ -318,7 +325,9 @@ static void print_stats(MSMGContext *ms)
     ms->log_level = orig_log_level;
 }
 
-static int context_init(cGH *gh, int fd_stencil, const char *loglevel_str,
+static int context_init(cGH *gh, int fd_stencil, int maxiter, int nb_cycles,
+                        int nb_relax_pre, int nb_relax_post, double tol_residual,
+                        const char *loglevel_str,
                         MSMGContext **ctx)
 {
     MSMGContext *ms;
@@ -329,7 +338,12 @@ static int context_init(cGH *gh, int fd_stencil, const char *loglevel_str,
         return -ENOMEM;
 
     ms->gh = gh;
-    ms->fd_stencil = fd_stencil;
+    ms->fd_stencil    = fd_stencil;
+    ms->maxiter       = maxiter;
+    ms->nb_cycles     = nb_cycles;
+    ms->nb_relax_pre  = nb_relax_pre;
+    ms->nb_relax_post = nb_relax_post;
+    ms->tol_residual  = tol_residual;
 
     for (int i = 0; i < ARRAY_ELEMS(log_levels); i++) {
         if (!strcmp(loglevel_str, log_levels[i].str)) {
@@ -869,7 +883,9 @@ void msa_mg_init(CCTK_ARGUMENTS)
     DECLARE_CCTK_PARAMETERS;
     int ret;
 
-    ret = context_init(cctkGH, fd_stencil, loglevel, &ms);
+    ret = context_init(cctkGH, fd_stencil, maxiter, nb_cycles,
+                       nb_relax_pre, nb_relax_post, tol_residual,
+                       loglevel, &ms);
     if (ret < 0)
         CCTK_WARN(0, "Error initializing the solver context");
 }
-- 
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