From d65bbd8aa6ca282ee116b978bc97b7f4b9d27e87 Mon Sep 17 00:00:00 2001
From: Spencer Bryngelson <sbryngelson@gmail.com>
Date: Fri, 20 Feb 2026 22:21:22 -0500
Subject: [PATCH 1/8] Fix WP_MOK hardcoded to 8 bytes, use storage_size for
 precision portability

MPI file offsets assume 8-byte reals. Single-precision builds would
read from wrong offsets. Use storage_size(0._wp)/8 instead.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 src/post_process/m_data_input.f90 | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/post_process/m_data_input.f90 b/src/post_process/m_data_input.f90
index a3e3f22886..6b87c585df 100644
--- a/src/post_process/m_data_input.f90
+++ b/src/post_process/m_data_input.f90
@@ -133,7 +133,7 @@ impure subroutine s_setup_mpi_io_params(data_size, m_MOK, n_MOK, p_MOK, WP_MOK,
         m_MOK = int(m_glb + 1, MPI_OFFSET_KIND)
         n_MOK = int(n_glb + 1, MPI_OFFSET_KIND)
         p_MOK = int(p_glb + 1, MPI_OFFSET_KIND)
-        WP_MOK = int(8._wp, MPI_OFFSET_KIND)
+        WP_MOK = int(storage_size(0._wp)/8, MPI_OFFSET_KIND)
         MOK = int(1._wp, MPI_OFFSET_KIND)
         str_MOK = int(name_len, MPI_OFFSET_KIND)
         NVARS_MOK = int(sys_size, MPI_OFFSET_KIND)
@@ -177,7 +177,7 @@ impure subroutine s_read_ib_data_files(file_loc_base, t_step)
                 n_MOK = int(n_glb + 1, MPI_OFFSET_KIND)
                 p_MOK = int(p_glb + 1, MPI_OFFSET_KIND)
                 MOK = int(1._wp, MPI_OFFSET_KIND)
-                WP_MOK = int(8._wp, MPI_OFFSET_KIND)
+                WP_MOK = int(storage_size(0._wp)/8, MPI_OFFSET_KIND)
                 save_index = t_step/t_step_save ! get the number of saves done to this point
 
                 data_size = (m + 1)*(n + 1)*(p + 1)
@@ -517,7 +517,7 @@ impure subroutine s_read_parallel_conservative_data(t_step, m_MOK, n_MOK, p_MOK,
                 m_MOK = int(m_glb + 1, MPI_OFFSET_KIND)
                 n_MOK = int(n_glb + 1, MPI_OFFSET_KIND)
                 p_MOK = int(p_glb + 1, MPI_OFFSET_KIND)
-                WP_MOK = int(8._wp, MPI_OFFSET_KIND)
+                WP_MOK = int(storage_size(0._wp)/8, MPI_OFFSET_KIND)
                 MOK = int(1._wp, MPI_OFFSET_KIND)
                 str_MOK = int(name_len, MPI_OFFSET_KIND)
                 NVARS_MOK = int(sys_size, MPI_OFFSET_KIND)

From c260aadfe1bbcaee66cd97c434e2a1529495e849 Mon Sep 17 00:00:00 2001
From: Spencer Bryngelson <sbryngelson@gmail.com>
Date: Sat, 21 Feb 2026 00:31:25 -0500
Subject: [PATCH 2/8] Extend storage_size fix to simulation and pre_process
 MPI-IO

The same int(8._wp, MPI_OFFSET_KIND) pattern that was fixed in
post_process/m_data_input.f90 was present in 7 additional locations
across simulation/m_data_output.fpp, simulation/m_start_up.fpp,
pre_process/m_data_output.fpp, and pre_process/m_start_up.fpp.
All hardcoded 8-byte strides are replaced with storage_size(0._wp)/8
so MPI file offsets are correct in single-precision builds.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 src/pre_process/m_data_output.fpp | 4 ++--
 src/pre_process/m_start_up.fpp    | 2 +-
 src/simulation/m_data_output.fpp  | 6 +++---
 src/simulation/m_start_up.fpp     | 2 +-
 4 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/pre_process/m_data_output.fpp b/src/pre_process/m_data_output.fpp
index bac4fdc038..8a34f7b17a 100644
--- a/src/pre_process/m_data_output.fpp
+++ b/src/pre_process/m_data_output.fpp
@@ -549,7 +549,7 @@ contains
             m_MOK = int(m_glb_save, MPI_OFFSET_KIND)
             n_MOK = int(n_glb_save, MPI_OFFSET_KIND)
             p_MOK = int(p_glb_save, MPI_OFFSET_KIND)
-            WP_MOK = int(8._wp, MPI_OFFSET_KIND)
+            WP_MOK = int(storage_size(0._wp)/8, MPI_OFFSET_KIND)
             MOK = int(1._wp, MPI_OFFSET_KIND)
             str_MOK = int(name_len, MPI_OFFSET_KIND)
             NVARS_MOK = int(sys_size, MPI_OFFSET_KIND)
@@ -615,7 +615,7 @@ contains
             m_MOK = int(m_glb + 1, MPI_OFFSET_KIND)
             n_MOK = int(n_glb + 1, MPI_OFFSET_KIND)
             p_MOK = int(p_glb + 1, MPI_OFFSET_KIND)
-            WP_MOK = int(8._wp, MPI_OFFSET_KIND)
+            WP_MOK = int(storage_size(0._wp)/8, MPI_OFFSET_KIND)
             MOK = int(1._wp, MPI_OFFSET_KIND)
             str_MOK = int(name_len, MPI_OFFSET_KIND)
             NVARS_MOK = int(sys_size, MPI_OFFSET_KIND)
diff --git a/src/pre_process/m_start_up.fpp b/src/pre_process/m_start_up.fpp
index 3b45547c29..dbd6ce211d 100644
--- a/src/pre_process/m_start_up.fpp
+++ b/src/pre_process/m_start_up.fpp
@@ -660,7 +660,7 @@ contains
             m_MOK = int(m_glb + 1, MPI_OFFSET_KIND)
             n_MOK = int(n_glb + 1, MPI_OFFSET_KIND)
             p_MOK = int(p_glb + 1, MPI_OFFSET_KIND)
-            WP_MOK = int(8._wp, MPI_OFFSET_KIND)
+            WP_MOK = int(storage_size(0._wp)/8, MPI_OFFSET_KIND)
             MOK = int(1._wp, MPI_OFFSET_KIND)
             str_MOK = int(name_len, MPI_OFFSET_KIND)
             NVARS_MOK = int(sys_size, MPI_OFFSET_KIND)
diff --git a/src/simulation/m_data_output.fpp b/src/simulation/m_data_output.fpp
index 5051d5e15d..d239f61ee6 100644
--- a/src/simulation/m_data_output.fpp
+++ b/src/simulation/m_data_output.fpp
@@ -895,7 +895,7 @@ contains
             m_MOK = int(m_glb_save + 1, MPI_OFFSET_KIND)
             n_MOK = int(n_glb_save + 1, MPI_OFFSET_KIND)
             p_MOK = int(p_glb_save + 1, MPI_OFFSET_KIND)
-            WP_MOK = int(8._wp, MPI_OFFSET_KIND)
+            WP_MOK = int(storage_size(0._wp)/8, MPI_OFFSET_KIND)
             MOK = int(1._wp, MPI_OFFSET_KIND)
             str_MOK = int(name_len, MPI_OFFSET_KIND)
             NVARS_MOK = int(sys_size, MPI_OFFSET_KIND)
@@ -963,7 +963,7 @@ contains
             m_MOK = int(m_glb + 1, MPI_OFFSET_KIND)
             n_MOK = int(n_glb + 1, MPI_OFFSET_KIND)
             p_MOK = int(p_glb + 1, MPI_OFFSET_KIND)
-            WP_MOK = int(8._wp, MPI_OFFSET_KIND)
+            WP_MOK = int(storage_size(0._wp)/8, MPI_OFFSET_KIND)
             MOK = int(1._wp, MPI_OFFSET_KIND)
             str_MOK = int(name_len, MPI_OFFSET_KIND)
             NVARS_MOK = int(alt_sys, MPI_OFFSET_KIND)
@@ -1087,7 +1087,7 @@ contains
         m_MOK = int(m_glb + 1, MPI_OFFSET_KIND)
         n_MOK = int(n_glb + 1, MPI_OFFSET_KIND)
         p_MOK = int(p_glb + 1, MPI_OFFSET_KIND)
-        WP_MOK = int(8._wp, MPI_OFFSET_KIND)
+        WP_MOK = int(storage_size(0._wp)/8, MPI_OFFSET_KIND)
         MOK = int(1._wp, MPI_OFFSET_KIND)
 
         write (file_loc, '(A)') 'ib.dat'
diff --git a/src/simulation/m_start_up.fpp b/src/simulation/m_start_up.fpp
index d8d0c87417..793ee2a25c 100644
--- a/src/simulation/m_start_up.fpp
+++ b/src/simulation/m_start_up.fpp
@@ -652,7 +652,7 @@ contains
                 m_MOK = int(m_glb + 1, MPI_OFFSET_KIND)
                 n_MOK = int(n_glb + 1, MPI_OFFSET_KIND)
                 p_MOK = int(p_glb + 1, MPI_OFFSET_KIND)
-                WP_MOK = int(8._wp, MPI_OFFSET_KIND)
+                WP_MOK = int(storage_size(0._wp)/8, MPI_OFFSET_KIND)
                 MOK = int(1._wp, MPI_OFFSET_KIND)
                 str_MOK = int(name_len, MPI_OFFSET_KIND)
                 NVARS_MOK = int(sys_size, MPI_OFFSET_KIND)

From bbfef040c3a5aeb8205d0912efd6223d03b4b640 Mon Sep 17 00:00:00 2001
From: Spencer Bryngelson <sbryngelson@gmail.com>
Date: Tue, 24 Feb 2026 15:13:30 -0500
Subject: [PATCH 3/8] Fix IB marker stride using WP size instead of integer
 size

IB markers are MPI_INTEGER (4 bytes), but WP_MOK was computed as
storage_size(0._wp)/8 = 8 bytes in double precision, causing a factor-of-2
displacement error when writing/reading ib.dat via MPI-IO.

Fix by using storage_size(0)/8 (default integer byte size) at the two
IB-specific MPI-IO displacement sites:
- src/simulation/m_data_output.fpp (s_write_parallel_ib_data)
- src/post_process/m_data_input.f90 (s_read_ib_data_files)

Also fix the Lustre restart read path in src/simulation/m_start_up.fpp
which had WP_MOK hardcoded to 4 instead of storage_size(0._wp)/8.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 src/post_process/m_data_input.f90 | 2 +-
 src/simulation/m_data_output.fpp  | 2 +-
 src/simulation/m_start_up.fpp     | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/post_process/m_data_input.f90 b/src/post_process/m_data_input.f90
index 6b87c585df..498a78c0a4 100644
--- a/src/post_process/m_data_input.f90
+++ b/src/post_process/m_data_input.f90
@@ -177,7 +177,7 @@ impure subroutine s_read_ib_data_files(file_loc_base, t_step)
                 n_MOK = int(n_glb + 1, MPI_OFFSET_KIND)
                 p_MOK = int(p_glb + 1, MPI_OFFSET_KIND)
                 MOK = int(1._wp, MPI_OFFSET_KIND)
-                WP_MOK = int(storage_size(0._wp)/8, MPI_OFFSET_KIND)
+                WP_MOK = int(storage_size(0)/8, MPI_OFFSET_KIND)
                 save_index = t_step/t_step_save ! get the number of saves done to this point
 
                 data_size = (m + 1)*(n + 1)*(p + 1)
diff --git a/src/simulation/m_data_output.fpp b/src/simulation/m_data_output.fpp
index d239f61ee6..bf076951c4 100644
--- a/src/simulation/m_data_output.fpp
+++ b/src/simulation/m_data_output.fpp
@@ -1087,7 +1087,7 @@ contains
         m_MOK = int(m_glb + 1, MPI_OFFSET_KIND)
         n_MOK = int(n_glb + 1, MPI_OFFSET_KIND)
         p_MOK = int(p_glb + 1, MPI_OFFSET_KIND)
-        WP_MOK = int(storage_size(0._wp)/8, MPI_OFFSET_KIND)
+        WP_MOK = int(storage_size(0)/8, MPI_OFFSET_KIND)
         MOK = int(1._wp, MPI_OFFSET_KIND)
 
         write (file_loc, '(A)') 'ib.dat'
diff --git a/src/simulation/m_start_up.fpp b/src/simulation/m_start_up.fpp
index 793ee2a25c..3d77255b41 100644
--- a/src/simulation/m_start_up.fpp
+++ b/src/simulation/m_start_up.fpp
@@ -575,7 +575,7 @@ contains
                 m_MOK = int(m_glb_read + 1, MPI_OFFSET_KIND)
                 n_MOK = int(m_glb_read + 1, MPI_OFFSET_KIND)
                 p_MOK = int(m_glb_read + 1, MPI_OFFSET_KIND)
-                WP_MOK = int(4._wp, MPI_OFFSET_KIND)
+                WP_MOK = int(storage_size(0._wp)/8, MPI_OFFSET_KIND)
                 MOK = int(1._wp, MPI_OFFSET_KIND)
                 str_MOK = int(name_len, MPI_OFFSET_KIND)
                 NVARS_MOK = int(sys_size, MPI_OFFSET_KIND)

From b047d7f794f1eaeb0c4f8ceb431ed78904210bfc Mon Sep 17 00:00:00 2001
From: Spencer Bryngelson <sbryngelson@gmail.com>
Date: Tue, 24 Feb 2026 16:16:40 -0500
Subject: [PATCH 4/8] Fix WP_MOK to use stp instead of wp for main field data
 I/O
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

MPI-IO displacement (WP_MOK) must match the storage precision of
the data being read/written.  Main field variables are written with
mpi_io_p (which tracks stp), not mpi_p (which tracks wp).  In
mixed-precision mode stp = half (2 bytes) while wp = double (8 bytes),
so using storage_size(0._wp) gives a 4× wrong displacement.

Change all main-data WP_MOK assignments from storage_size(0._wp) to
storage_size(0._stp) across all three I/O paths:
  - src/simulation/m_data_output.fpp (write, two call sites)
  - src/simulation/m_start_up.fpp    (restart read, two call sites)
  - src/post_process/m_data_input.f90 (post-process read, two call sites)

IB marker I/O (MPI_INTEGER, 4 bytes) was already fixed to use
storage_size(0)/8 in the previous commit and is not changed here.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 src/post_process/m_data_input.f90 | 4 ++--
 src/simulation/m_data_output.fpp  | 4 ++--
 src/simulation/m_start_up.fpp     | 4 ++--
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/post_process/m_data_input.f90 b/src/post_process/m_data_input.f90
index 498a78c0a4..933f4274fe 100644
--- a/src/post_process/m_data_input.f90
+++ b/src/post_process/m_data_input.f90
@@ -133,7 +133,7 @@ impure subroutine s_setup_mpi_io_params(data_size, m_MOK, n_MOK, p_MOK, WP_MOK,
         m_MOK = int(m_glb + 1, MPI_OFFSET_KIND)
         n_MOK = int(n_glb + 1, MPI_OFFSET_KIND)
         p_MOK = int(p_glb + 1, MPI_OFFSET_KIND)
-        WP_MOK = int(storage_size(0._wp)/8, MPI_OFFSET_KIND)
+        WP_MOK = int(storage_size(0._stp)/8, MPI_OFFSET_KIND)
         MOK = int(1._wp, MPI_OFFSET_KIND)
         str_MOK = int(name_len, MPI_OFFSET_KIND)
         NVARS_MOK = int(sys_size, MPI_OFFSET_KIND)
@@ -517,7 +517,7 @@ impure subroutine s_read_parallel_conservative_data(t_step, m_MOK, n_MOK, p_MOK,
                 m_MOK = int(m_glb + 1, MPI_OFFSET_KIND)
                 n_MOK = int(n_glb + 1, MPI_OFFSET_KIND)
                 p_MOK = int(p_glb + 1, MPI_OFFSET_KIND)
-                WP_MOK = int(storage_size(0._wp)/8, MPI_OFFSET_KIND)
+                WP_MOK = int(storage_size(0._stp)/8, MPI_OFFSET_KIND)
                 MOK = int(1._wp, MPI_OFFSET_KIND)
                 str_MOK = int(name_len, MPI_OFFSET_KIND)
                 NVARS_MOK = int(sys_size, MPI_OFFSET_KIND)
diff --git a/src/simulation/m_data_output.fpp b/src/simulation/m_data_output.fpp
index bf076951c4..b1b3c7a1a4 100644
--- a/src/simulation/m_data_output.fpp
+++ b/src/simulation/m_data_output.fpp
@@ -895,7 +895,7 @@ contains
             m_MOK = int(m_glb_save + 1, MPI_OFFSET_KIND)
             n_MOK = int(n_glb_save + 1, MPI_OFFSET_KIND)
             p_MOK = int(p_glb_save + 1, MPI_OFFSET_KIND)
-            WP_MOK = int(storage_size(0._wp)/8, MPI_OFFSET_KIND)
+            WP_MOK = int(storage_size(0._stp)/8, MPI_OFFSET_KIND)
             MOK = int(1._wp, MPI_OFFSET_KIND)
             str_MOK = int(name_len, MPI_OFFSET_KIND)
             NVARS_MOK = int(sys_size, MPI_OFFSET_KIND)
@@ -963,7 +963,7 @@ contains
             m_MOK = int(m_glb + 1, MPI_OFFSET_KIND)
             n_MOK = int(n_glb + 1, MPI_OFFSET_KIND)
             p_MOK = int(p_glb + 1, MPI_OFFSET_KIND)
-            WP_MOK = int(storage_size(0._wp)/8, MPI_OFFSET_KIND)
+            WP_MOK = int(storage_size(0._stp)/8, MPI_OFFSET_KIND)
             MOK = int(1._wp, MPI_OFFSET_KIND)
             str_MOK = int(name_len, MPI_OFFSET_KIND)
             NVARS_MOK = int(alt_sys, MPI_OFFSET_KIND)
diff --git a/src/simulation/m_start_up.fpp b/src/simulation/m_start_up.fpp
index 3d77255b41..3faf27b27a 100644
--- a/src/simulation/m_start_up.fpp
+++ b/src/simulation/m_start_up.fpp
@@ -575,7 +575,7 @@ contains
                 m_MOK = int(m_glb_read + 1, MPI_OFFSET_KIND)
                 n_MOK = int(m_glb_read + 1, MPI_OFFSET_KIND)
                 p_MOK = int(m_glb_read + 1, MPI_OFFSET_KIND)
-                WP_MOK = int(storage_size(0._wp)/8, MPI_OFFSET_KIND)
+                WP_MOK = int(storage_size(0._stp)/8, MPI_OFFSET_KIND)
                 MOK = int(1._wp, MPI_OFFSET_KIND)
                 str_MOK = int(name_len, MPI_OFFSET_KIND)
                 NVARS_MOK = int(sys_size, MPI_OFFSET_KIND)
@@ -652,7 +652,7 @@ contains
                 m_MOK = int(m_glb + 1, MPI_OFFSET_KIND)
                 n_MOK = int(n_glb + 1, MPI_OFFSET_KIND)
                 p_MOK = int(p_glb + 1, MPI_OFFSET_KIND)
-                WP_MOK = int(storage_size(0._wp)/8, MPI_OFFSET_KIND)
+                WP_MOK = int(storage_size(0._stp)/8, MPI_OFFSET_KIND)
                 MOK = int(1._wp, MPI_OFFSET_KIND)
                 str_MOK = int(name_len, MPI_OFFSET_KIND)
                 NVARS_MOK = int(sys_size, MPI_OFFSET_KIND)

From 2f6dd049eb07162ed5ce032d1ab83ba87df82439 Mon Sep 17 00:00:00 2001
From: Spencer Bryngelson <sbryngelson@gmail.com>
Date: Wed, 25 Feb 2026 23:26:00 -0500
Subject: [PATCH 5/8] Fix typo in m_start_up.fpp: equilirium -> equilibrium

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 src/pre_process/m_start_up.fpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/pre_process/m_start_up.fpp b/src/pre_process/m_start_up.fpp
index dbd6ce211d..1e7528c27e 100644
--- a/src/pre_process/m_start_up.fpp
+++ b/src/pre_process/m_start_up.fpp
@@ -798,7 +798,7 @@ contains
         if (relax) then
             if (proc_rank == 0) then
                 print *, 'initial condition might have been altered due to enforcement of &
-&                pTg-equilirium (relax = "T" activated)'
+&                pTg-equilibrium (relax = "T" activated)'
             end if
 
             call s_infinite_relaxation_k(q_cons_vf)

From 21e1e5dd6fdec84858330509c53948d4879737c7 Mon Sep 17 00:00:00 2001
From: Spencer Bryngelson <sbryngelson@gmail.com>
Date: Thu, 26 Feb 2026 00:22:54 -0500
Subject: [PATCH 6/8] Fix wp -> stp in pre_process I/O and remove dead Lustre
 block

Pre-process MPI I/O strides should use storage precision (stp) not
working precision (wp) since field arrays use stp. Also removes the
dead file_per_process sequential-read path that contained known
copy-paste bugs (n_MOK/p_MOK both using m_glb_read).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 src/pre_process/m_data_output.fpp |   4 +-
 src/pre_process/m_start_up.fpp    |   2 +-
 src/simulation/m_start_up.fpp     | 209 +++++++++---------------------
 3 files changed, 61 insertions(+), 154 deletions(-)

diff --git a/src/pre_process/m_data_output.fpp b/src/pre_process/m_data_output.fpp
index 8a34f7b17a..bf07702bf8 100644
--- a/src/pre_process/m_data_output.fpp
+++ b/src/pre_process/m_data_output.fpp
@@ -549,7 +549,7 @@ contains
             m_MOK = int(m_glb_save, MPI_OFFSET_KIND)
             n_MOK = int(n_glb_save, MPI_OFFSET_KIND)
             p_MOK = int(p_glb_save, MPI_OFFSET_KIND)
-            WP_MOK = int(storage_size(0._wp)/8, MPI_OFFSET_KIND)
+            WP_MOK = int(storage_size(0._stp)/8, MPI_OFFSET_KIND)
             MOK = int(1._wp, MPI_OFFSET_KIND)
             str_MOK = int(name_len, MPI_OFFSET_KIND)
             NVARS_MOK = int(sys_size, MPI_OFFSET_KIND)
@@ -615,7 +615,7 @@ contains
             m_MOK = int(m_glb + 1, MPI_OFFSET_KIND)
             n_MOK = int(n_glb + 1, MPI_OFFSET_KIND)
             p_MOK = int(p_glb + 1, MPI_OFFSET_KIND)
-            WP_MOK = int(storage_size(0._wp)/8, MPI_OFFSET_KIND)
+            WP_MOK = int(storage_size(0._stp)/8, MPI_OFFSET_KIND)
             MOK = int(1._wp, MPI_OFFSET_KIND)
             str_MOK = int(name_len, MPI_OFFSET_KIND)
             NVARS_MOK = int(sys_size, MPI_OFFSET_KIND)
diff --git a/src/pre_process/m_start_up.fpp b/src/pre_process/m_start_up.fpp
index 1e7528c27e..42725bc3dd 100644
--- a/src/pre_process/m_start_up.fpp
+++ b/src/pre_process/m_start_up.fpp
@@ -660,7 +660,7 @@ contains
             m_MOK = int(m_glb + 1, MPI_OFFSET_KIND)
             n_MOK = int(n_glb + 1, MPI_OFFSET_KIND)
             p_MOK = int(p_glb + 1, MPI_OFFSET_KIND)
-            WP_MOK = int(storage_size(0._wp)/8, MPI_OFFSET_KIND)
+            WP_MOK = int(storage_size(0._stp)/8, MPI_OFFSET_KIND)
             MOK = int(1._wp, MPI_OFFSET_KIND)
             str_MOK = int(name_len, MPI_OFFSET_KIND)
             NVARS_MOK = int(sys_size, MPI_OFFSET_KIND)
diff --git a/src/simulation/m_start_up.fpp b/src/simulation/m_start_up.fpp
index 3faf27b27a..1aa1435938 100644
--- a/src/simulation/m_start_up.fpp
+++ b/src/simulation/m_start_up.fpp
@@ -532,134 +532,55 @@ contains
             end if
         end if
 
-        if (file_per_process) then
-            if (cfl_dt) then
-                call s_int_to_str(n_start, t_step_start_string)
-                write (file_loc, '(I0,A1,I7.7,A)') n_start, '_', proc_rank, '.dat'
-            else
-                call s_int_to_str(t_step_start, t_step_start_string)
-                write (file_loc, '(I0,A1,I7.7,A)') t_step_start, '_', proc_rank, '.dat'
-            end if
-            file_loc = trim(case_dir)//'/restart_data/lustre_'//trim(t_step_start_string)//trim(mpiiofs)//trim(file_loc)
-            inquire (FILE=trim(file_loc), EXIST=file_exist)
-
-            if (file_exist) then
-                call MPI_FILE_OPEN(MPI_COMM_SELF, file_loc, MPI_MODE_RDONLY, mpi_info_int, ifile, ierr)
-
-                ! Initialize MPI data I/O
-                if (down_sample) then
-                    call s_initialize_mpi_data_ds(q_cons_vf)
-                else
-                    if (ib) then
-                        call s_initialize_mpi_data(q_cons_vf, ib_markers)
-                    else
-                        call s_initialize_mpi_data(q_cons_vf)
-                    end if
-                end if
-
-                if (down_sample) then
-                    ! Size of local arrays
-                    data_size = (m_ds + 3)*(n_ds + 3)*(p_ds + 3)
-                    m_glb_read = m_glb_ds + 1
-                    n_glb_read = n_glb_ds + 1
-                    p_glb_read = p_glb_ds + 1
-                else
-                    ! Size of local arrays
-                    data_size = (m + 1)*(n + 1)*(p + 1)
-                    m_glb_read = m_glb + 1
-                    n_glb_read = n_glb + 1
-                    p_glb_read = p_glb + 1
-                end if
-
-                ! Resize some integers so MPI can read even the biggest file
-                m_MOK = int(m_glb_read + 1, MPI_OFFSET_KIND)
-                n_MOK = int(m_glb_read + 1, MPI_OFFSET_KIND)
-                p_MOK = int(m_glb_read + 1, MPI_OFFSET_KIND)
-                WP_MOK = int(storage_size(0._stp)/8, MPI_OFFSET_KIND)
-                MOK = int(1._wp, MPI_OFFSET_KIND)
-                str_MOK = int(name_len, MPI_OFFSET_KIND)
-                NVARS_MOK = int(sys_size, MPI_OFFSET_KIND)
-
-                ! Read the data for each variable
-                if (bubbles_euler .or. elasticity) then
-                    do i = 1, sys_size!adv_idx%end
-                        var_MOK = int(i, MPI_OFFSET_KIND)
-
-                        call MPI_FILE_READ(ifile, MPI_IO_DATA%var(i)%sf, data_size*mpi_io_type, &
-                                           mpi_io_p, status, ierr)
-                    end do
-                    !Read pb and mv for non-polytropic qbmm
-                    if (qbmm .and. .not. polytropic) then
-                        do i = sys_size + 1, sys_size + 2*nb*nnode
-                            var_MOK = int(i, MPI_OFFSET_KIND)
-
-                            call MPI_FILE_READ(ifile, MPI_IO_DATA%var(i)%sf, data_size*mpi_io_type, &
-                                               mpi_io_p, status, ierr)
-                        end do
-                    end if
-                else
-                    if (down_sample) then
-                        do i = 1, sys_size
-                            var_MOK = int(i, MPI_OFFSET_KIND)
-
-                            call MPI_FILE_READ(ifile, q_cons_temp(i)%sf, data_size*mpi_io_type, &
-                                               mpi_io_p, status, ierr)
-                        end do
-                    else
-                        do i = 1, sys_size
-                            var_MOK = int(i, MPI_OFFSET_KIND)
-
-                            call MPI_FILE_READ(ifile, MPI_IO_DATA%var(i)%sf, data_size*mpi_io_type, &
-                                               mpi_io_p, status, ierr)
-                        end do
-                    end if
-                end if
-
-                call s_mpi_barrier()
-
-                call MPI_FILE_CLOSE(ifile, ierr)
-
-            else
-                call s_mpi_abort('File '//trim(file_loc)//' is missing. Exiting.')
-            end if
+        ! Open the file to read conservative variables
+        if (cfl_dt) then
+            write (file_loc, '(I0,A)') n_start, '.dat'
         else
-            ! Open the file to read conservative variables
-            if (cfl_dt) then
-                write (file_loc, '(I0,A)') n_start, '.dat'
-            else
-                write (file_loc, '(I0,A)') t_step_start, '.dat'
-            end if
-            file_loc = trim(case_dir)//'/restart_data'//trim(mpiiofs)//trim(file_loc)
-            inquire (FILE=trim(file_loc), EXIST=file_exist)
+            write (file_loc, '(I0,A)') t_step_start, '.dat'
+        end if
+        file_loc = trim(case_dir)//'/restart_data'//trim(mpiiofs)//trim(file_loc)
+        inquire (FILE=trim(file_loc), EXIST=file_exist)
 
-            if (file_exist) then
-                call MPI_FILE_OPEN(MPI_COMM_WORLD, file_loc, MPI_MODE_RDONLY, mpi_info_int, ifile, ierr)
+        if (file_exist) then
+            call MPI_FILE_OPEN(MPI_COMM_WORLD, file_loc, MPI_MODE_RDONLY, mpi_info_int, ifile, ierr)
 
-                ! Initialize MPI data I/O
+            ! Initialize MPI data I/O
 
-                if (ib) then
-                    call s_initialize_mpi_data(q_cons_vf, ib_markers)
-                else
+            if (ib) then
+                call s_initialize_mpi_data(q_cons_vf, ib_markers)
+            else
 
-                    call s_initialize_mpi_data(q_cons_vf)
+                call s_initialize_mpi_data(q_cons_vf)
 
-                end if
+            end if
 
-                ! Size of local arrays
-                data_size = (m + 1)*(n + 1)*(p + 1)
-
-                ! Resize some integers so MPI can read even the biggest file
-                m_MOK = int(m_glb + 1, MPI_OFFSET_KIND)
-                n_MOK = int(n_glb + 1, MPI_OFFSET_KIND)
-                p_MOK = int(p_glb + 1, MPI_OFFSET_KIND)
-                WP_MOK = int(storage_size(0._stp)/8, MPI_OFFSET_KIND)
-                MOK = int(1._wp, MPI_OFFSET_KIND)
-                str_MOK = int(name_len, MPI_OFFSET_KIND)
-                NVARS_MOK = int(sys_size, MPI_OFFSET_KIND)
-
-                ! Read the data for each variable
-                if (bubbles_euler .or. elasticity) then
-                    do i = 1, sys_size !adv_idx%end
+            ! Size of local arrays
+            data_size = (m + 1)*(n + 1)*(p + 1)
+
+            ! Resize some integers so MPI can read even the biggest file
+            m_MOK = int(m_glb + 1, MPI_OFFSET_KIND)
+            n_MOK = int(n_glb + 1, MPI_OFFSET_KIND)
+            p_MOK = int(p_glb + 1, MPI_OFFSET_KIND)
+            WP_MOK = int(storage_size(0._stp)/8, MPI_OFFSET_KIND)
+            MOK = int(1._wp, MPI_OFFSET_KIND)
+            str_MOK = int(name_len, MPI_OFFSET_KIND)
+            NVARS_MOK = int(sys_size, MPI_OFFSET_KIND)
+
+            ! Read the data for each variable
+            if (bubbles_euler .or. elasticity) then
+                do i = 1, sys_size !adv_idx%end
+                    var_MOK = int(i, MPI_OFFSET_KIND)
+                    ! Initial displacement to skip at beginning of file
+                    disp = m_MOK*max(MOK, n_MOK)*max(MOK, p_MOK)*WP_MOK*(var_MOK - 1)
+
+                    call MPI_FILE_SET_VIEW(ifile, disp, mpi_io_p, MPI_IO_DATA%view(i), &
+                                           'native', mpi_info_int, ierr)
+                    call MPI_FILE_READ(ifile, MPI_IO_DATA%var(i)%sf, data_size*mpi_io_type, &
+                                       mpi_io_p, status, ierr)
+                end do
+                !Read pb and mv for non-polytropic qbmm
+                if (qbmm .and. .not. polytropic) then
+                    do i = sys_size + 1, sys_size + 2*nb*nnode
                         var_MOK = int(i, MPI_OFFSET_KIND)
                         ! Initial displacement to skip at beginning of file
                         disp = m_MOK*max(MOK, n_MOK)*max(MOK, p_MOK)*WP_MOK*(var_MOK - 1)
@@ -669,41 +590,27 @@ contains
                         call MPI_FILE_READ(ifile, MPI_IO_DATA%var(i)%sf, data_size*mpi_io_type, &
                                            mpi_io_p, status, ierr)
                     end do
-                    !Read pb and mv for non-polytropic qbmm
-                    if (qbmm .and. .not. polytropic) then
-                        do i = sys_size + 1, sys_size + 2*nb*nnode
-                            var_MOK = int(i, MPI_OFFSET_KIND)
-                            ! Initial displacement to skip at beginning of file
-                            disp = m_MOK*max(MOK, n_MOK)*max(MOK, p_MOK)*WP_MOK*(var_MOK - 1)
-
-                            call MPI_FILE_SET_VIEW(ifile, disp, mpi_io_p, MPI_IO_DATA%view(i), &
-                                                   'native', mpi_info_int, ierr)
-                            call MPI_FILE_READ(ifile, MPI_IO_DATA%var(i)%sf, data_size*mpi_io_type, &
-                                               mpi_io_p, status, ierr)
-                        end do
-                    end if
-                else
-                    do i = 1, sys_size
-                        var_MOK = int(i, MPI_OFFSET_KIND)
-
-                        ! Initial displacement to skip at beginning of file
-                        disp = m_MOK*max(MOK, n_MOK)*max(MOK, p_MOK)*WP_MOK*(var_MOK - 1)
-
-                        call MPI_FILE_SET_VIEW(ifile, disp, mpi_io_p, MPI_IO_DATA%view(i), &
-                                               'native', mpi_info_int, ierr)
-                        call MPI_FILE_READ_ALL(ifile, MPI_IO_DATA%var(i)%sf, data_size*mpi_io_type, &
-                                               mpi_io_p, status, ierr)
-                    end do
                 end if
+            else
+                do i = 1, sys_size
+                    var_MOK = int(i, MPI_OFFSET_KIND)
 
-                call s_mpi_barrier()
-
-                call MPI_FILE_CLOSE(ifile, ierr)
+                    ! Initial displacement to skip at beginning of file
+                    disp = m_MOK*max(MOK, n_MOK)*max(MOK, p_MOK)*WP_MOK*(var_MOK - 1)
 
-            else
-                call s_mpi_abort('File '//trim(file_loc)//' is missing. Exiting.')
+                    call MPI_FILE_SET_VIEW(ifile, disp, mpi_io_p, MPI_IO_DATA%view(i), &
+                                           'native', mpi_info_int, ierr)
+                    call MPI_FILE_READ_ALL(ifile, MPI_IO_DATA%var(i)%sf, data_size*mpi_io_type, &
+                                           mpi_io_p, status, ierr)
+                end do
             end if
 
+            call s_mpi_barrier()
+
+            call MPI_FILE_CLOSE(ifile, ierr)
+
+        else
+            call s_mpi_abort('File '//trim(file_loc)//' is missing. Exiting.')
         end if
 
         deallocate (x_cb_glb, y_cb_glb, z_cb_glb)

From 23d9466d3033e1047ef0e509e11b316ebc1dc6e6 Mon Sep 17 00:00:00 2001
From: Spencer Bryngelson <sbryngelson@gmail.com>
Date: Thu, 26 Feb 2026 00:50:34 -0500
Subject: [PATCH 7/8] Restore file_per_process Lustre sequential-read path

This code path is still used in practice on HPC clusters even though
it is not exercised by the test suite. Reverts the removal while
keeping the wp -> stp precision fix in both branches.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 src/simulation/m_start_up.fpp | 209 ++++++++++++++++++++++++----------
 1 file changed, 151 insertions(+), 58 deletions(-)

diff --git a/src/simulation/m_start_up.fpp b/src/simulation/m_start_up.fpp
index 1aa1435938..3faf27b27a 100644
--- a/src/simulation/m_start_up.fpp
+++ b/src/simulation/m_start_up.fpp
@@ -532,55 +532,134 @@ contains
             end if
         end if
 
-        ! Open the file to read conservative variables
-        if (cfl_dt) then
-            write (file_loc, '(I0,A)') n_start, '.dat'
-        else
-            write (file_loc, '(I0,A)') t_step_start, '.dat'
-        end if
-        file_loc = trim(case_dir)//'/restart_data'//trim(mpiiofs)//trim(file_loc)
-        inquire (FILE=trim(file_loc), EXIST=file_exist)
+        if (file_per_process) then
+            if (cfl_dt) then
+                call s_int_to_str(n_start, t_step_start_string)
+                write (file_loc, '(I0,A1,I7.7,A)') n_start, '_', proc_rank, '.dat'
+            else
+                call s_int_to_str(t_step_start, t_step_start_string)
+                write (file_loc, '(I0,A1,I7.7,A)') t_step_start, '_', proc_rank, '.dat'
+            end if
+            file_loc = trim(case_dir)//'/restart_data/lustre_'//trim(t_step_start_string)//trim(mpiiofs)//trim(file_loc)
+            inquire (FILE=trim(file_loc), EXIST=file_exist)
 
-        if (file_exist) then
-            call MPI_FILE_OPEN(MPI_COMM_WORLD, file_loc, MPI_MODE_RDONLY, mpi_info_int, ifile, ierr)
+            if (file_exist) then
+                call MPI_FILE_OPEN(MPI_COMM_SELF, file_loc, MPI_MODE_RDONLY, mpi_info_int, ifile, ierr)
 
-            ! Initialize MPI data I/O
+                ! Initialize MPI data I/O
+                if (down_sample) then
+                    call s_initialize_mpi_data_ds(q_cons_vf)
+                else
+                    if (ib) then
+                        call s_initialize_mpi_data(q_cons_vf, ib_markers)
+                    else
+                        call s_initialize_mpi_data(q_cons_vf)
+                    end if
+                end if
 
-            if (ib) then
-                call s_initialize_mpi_data(q_cons_vf, ib_markers)
-            else
+                if (down_sample) then
+                    ! Size of local arrays
+                    data_size = (m_ds + 3)*(n_ds + 3)*(p_ds + 3)
+                    m_glb_read = m_glb_ds + 1
+                    n_glb_read = n_glb_ds + 1
+                    p_glb_read = p_glb_ds + 1
+                else
+                    ! Size of local arrays
+                    data_size = (m + 1)*(n + 1)*(p + 1)
+                    m_glb_read = m_glb + 1
+                    n_glb_read = n_glb + 1
+                    p_glb_read = p_glb + 1
+                end if
 
-                call s_initialize_mpi_data(q_cons_vf)
+                ! Resize some integers so MPI can read even the biggest file
+                m_MOK = int(m_glb_read + 1, MPI_OFFSET_KIND)
+                n_MOK = int(m_glb_read + 1, MPI_OFFSET_KIND)
+                p_MOK = int(m_glb_read + 1, MPI_OFFSET_KIND)
+                WP_MOK = int(storage_size(0._stp)/8, MPI_OFFSET_KIND)
+                MOK = int(1._wp, MPI_OFFSET_KIND)
+                str_MOK = int(name_len, MPI_OFFSET_KIND)
+                NVARS_MOK = int(sys_size, MPI_OFFSET_KIND)
+
+                ! Read the data for each variable
+                if (bubbles_euler .or. elasticity) then
+                    do i = 1, sys_size!adv_idx%end
+                        var_MOK = int(i, MPI_OFFSET_KIND)
 
+                        call MPI_FILE_READ(ifile, MPI_IO_DATA%var(i)%sf, data_size*mpi_io_type, &
+                                           mpi_io_p, status, ierr)
+                    end do
+                    !Read pb and mv for non-polytropic qbmm
+                    if (qbmm .and. .not. polytropic) then
+                        do i = sys_size + 1, sys_size + 2*nb*nnode
+                            var_MOK = int(i, MPI_OFFSET_KIND)
+
+                            call MPI_FILE_READ(ifile, MPI_IO_DATA%var(i)%sf, data_size*mpi_io_type, &
+                                               mpi_io_p, status, ierr)
+                        end do
+                    end if
+                else
+                    if (down_sample) then
+                        do i = 1, sys_size
+                            var_MOK = int(i, MPI_OFFSET_KIND)
+
+                            call MPI_FILE_READ(ifile, q_cons_temp(i)%sf, data_size*mpi_io_type, &
+                                               mpi_io_p, status, ierr)
+                        end do
+                    else
+                        do i = 1, sys_size
+                            var_MOK = int(i, MPI_OFFSET_KIND)
+
+                            call MPI_FILE_READ(ifile, MPI_IO_DATA%var(i)%sf, data_size*mpi_io_type, &
+                                               mpi_io_p, status, ierr)
+                        end do
+                    end if
+                end if
+
+                call s_mpi_barrier()
+
+                call MPI_FILE_CLOSE(ifile, ierr)
+
+            else
+                call s_mpi_abort('File '//trim(file_loc)//' is missing. Exiting.')
             end if
+        else
+            ! Open the file to read conservative variables
+            if (cfl_dt) then
+                write (file_loc, '(I0,A)') n_start, '.dat'
+            else
+                write (file_loc, '(I0,A)') t_step_start, '.dat'
+            end if
+            file_loc = trim(case_dir)//'/restart_data'//trim(mpiiofs)//trim(file_loc)
+            inquire (FILE=trim(file_loc), EXIST=file_exist)
 
-            ! Size of local arrays
-            data_size = (m + 1)*(n + 1)*(p + 1)
-
-            ! Resize some integers so MPI can read even the biggest file
-            m_MOK = int(m_glb + 1, MPI_OFFSET_KIND)
-            n_MOK = int(n_glb + 1, MPI_OFFSET_KIND)
-            p_MOK = int(p_glb + 1, MPI_OFFSET_KIND)
-            WP_MOK = int(storage_size(0._stp)/8, MPI_OFFSET_KIND)
-            MOK = int(1._wp, MPI_OFFSET_KIND)
-            str_MOK = int(name_len, MPI_OFFSET_KIND)
-            NVARS_MOK = int(sys_size, MPI_OFFSET_KIND)
-
-            ! Read the data for each variable
-            if (bubbles_euler .or. elasticity) then
-                do i = 1, sys_size !adv_idx%end
-                    var_MOK = int(i, MPI_OFFSET_KIND)
-                    ! Initial displacement to skip at beginning of file
-                    disp = m_MOK*max(MOK, n_MOK)*max(MOK, p_MOK)*WP_MOK*(var_MOK - 1)
-
-                    call MPI_FILE_SET_VIEW(ifile, disp, mpi_io_p, MPI_IO_DATA%view(i), &
-                                           'native', mpi_info_int, ierr)
-                    call MPI_FILE_READ(ifile, MPI_IO_DATA%var(i)%sf, data_size*mpi_io_type, &
-                                       mpi_io_p, status, ierr)
-                end do
-                !Read pb and mv for non-polytropic qbmm
-                if (qbmm .and. .not. polytropic) then
-                    do i = sys_size + 1, sys_size + 2*nb*nnode
+            if (file_exist) then
+                call MPI_FILE_OPEN(MPI_COMM_WORLD, file_loc, MPI_MODE_RDONLY, mpi_info_int, ifile, ierr)
+
+                ! Initialize MPI data I/O
+
+                if (ib) then
+                    call s_initialize_mpi_data(q_cons_vf, ib_markers)
+                else
+
+                    call s_initialize_mpi_data(q_cons_vf)
+
+                end if
+
+                ! Size of local arrays
+                data_size = (m + 1)*(n + 1)*(p + 1)
+
+                ! Resize some integers so MPI can read even the biggest file
+                m_MOK = int(m_glb + 1, MPI_OFFSET_KIND)
+                n_MOK = int(n_glb + 1, MPI_OFFSET_KIND)
+                p_MOK = int(p_glb + 1, MPI_OFFSET_KIND)
+                WP_MOK = int(storage_size(0._stp)/8, MPI_OFFSET_KIND)
+                MOK = int(1._wp, MPI_OFFSET_KIND)
+                str_MOK = int(name_len, MPI_OFFSET_KIND)
+                NVARS_MOK = int(sys_size, MPI_OFFSET_KIND)
+
+                ! Read the data for each variable
+                if (bubbles_euler .or. elasticity) then
+                    do i = 1, sys_size !adv_idx%end
                         var_MOK = int(i, MPI_OFFSET_KIND)
                         ! Initial displacement to skip at beginning of file
                         disp = m_MOK*max(MOK, n_MOK)*max(MOK, p_MOK)*WP_MOK*(var_MOK - 1)
@@ -590,27 +669,41 @@ contains
                         call MPI_FILE_READ(ifile, MPI_IO_DATA%var(i)%sf, data_size*mpi_io_type, &
                                            mpi_io_p, status, ierr)
                     end do
-                end if
-            else
-                do i = 1, sys_size
-                    var_MOK = int(i, MPI_OFFSET_KIND)
+                    !Read pb and mv for non-polytropic qbmm
+                    if (qbmm .and. .not. polytropic) then
+                        do i = sys_size + 1, sys_size + 2*nb*nnode
+                            var_MOK = int(i, MPI_OFFSET_KIND)
+                            ! Initial displacement to skip at beginning of file
+                            disp = m_MOK*max(MOK, n_MOK)*max(MOK, p_MOK)*WP_MOK*(var_MOK - 1)
+
+                            call MPI_FILE_SET_VIEW(ifile, disp, mpi_io_p, MPI_IO_DATA%view(i), &
+                                                   'native', mpi_info_int, ierr)
+                            call MPI_FILE_READ(ifile, MPI_IO_DATA%var(i)%sf, data_size*mpi_io_type, &
+                                               mpi_io_p, status, ierr)
+                        end do
+                    end if
+                else
+                    do i = 1, sys_size
+                        var_MOK = int(i, MPI_OFFSET_KIND)
 
-                    ! Initial displacement to skip at beginning of file
-                    disp = m_MOK*max(MOK, n_MOK)*max(MOK, p_MOK)*WP_MOK*(var_MOK - 1)
+                        ! Initial displacement to skip at beginning of file
+                        disp = m_MOK*max(MOK, n_MOK)*max(MOK, p_MOK)*WP_MOK*(var_MOK - 1)
 
-                    call MPI_FILE_SET_VIEW(ifile, disp, mpi_io_p, MPI_IO_DATA%view(i), &
-                                           'native', mpi_info_int, ierr)
-                    call MPI_FILE_READ_ALL(ifile, MPI_IO_DATA%var(i)%sf, data_size*mpi_io_type, &
-                                           mpi_io_p, status, ierr)
-                end do
-            end if
+                        call MPI_FILE_SET_VIEW(ifile, disp, mpi_io_p, MPI_IO_DATA%view(i), &
+                                               'native', mpi_info_int, ierr)
+                        call MPI_FILE_READ_ALL(ifile, MPI_IO_DATA%var(i)%sf, data_size*mpi_io_type, &
+                                               mpi_io_p, status, ierr)
+                    end do
+                end if
 
-            call s_mpi_barrier()
+                call s_mpi_barrier()
 
-            call MPI_FILE_CLOSE(ifile, ierr)
+                call MPI_FILE_CLOSE(ifile, ierr)
+
+            else
+                call s_mpi_abort('File '//trim(file_loc)//' is missing. Exiting.')
+            end if
 
-        else
-            call s_mpi_abort('File '//trim(file_loc)//' is missing. Exiting.')
         end if
 
         deallocate (x_cb_glb, y_cb_glb, z_cb_glb)

From 1cdea6b0b9d036859e796b8ef9a7fc56211e797c Mon Sep 17 00:00:00 2001
From: Spencer Bryngelson <sbryngelson@gmail.com>
Date: Thu, 26 Feb 2026 00:56:52 -0500
Subject: [PATCH 8/8] Fix IB data WP_MOK to use stp instead of default integer

The IB read/write displacement formula uses WP_MOK to skip past
floating-point field data. Using storage_size(0) gave the default
integer size (4 bytes), not the field storage precision size, causing
incorrect byte offsets in double-precision builds.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 src/post_process/m_data_input.f90 | 2 +-
 src/simulation/m_data_output.fpp  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/post_process/m_data_input.f90 b/src/post_process/m_data_input.f90
index 933f4274fe..e1dc941682 100644
--- a/src/post_process/m_data_input.f90
+++ b/src/post_process/m_data_input.f90
@@ -177,7 +177,7 @@ impure subroutine s_read_ib_data_files(file_loc_base, t_step)
                 n_MOK = int(n_glb + 1, MPI_OFFSET_KIND)
                 p_MOK = int(p_glb + 1, MPI_OFFSET_KIND)
                 MOK = int(1._wp, MPI_OFFSET_KIND)
-                WP_MOK = int(storage_size(0)/8, MPI_OFFSET_KIND)
+                WP_MOK = int(storage_size(0._stp)/8, MPI_OFFSET_KIND)
                 save_index = t_step/t_step_save ! get the number of saves done to this point
 
                 data_size = (m + 1)*(n + 1)*(p + 1)
diff --git a/src/simulation/m_data_output.fpp b/src/simulation/m_data_output.fpp
index b1b3c7a1a4..5760e33089 100644
--- a/src/simulation/m_data_output.fpp
+++ b/src/simulation/m_data_output.fpp
@@ -1087,7 +1087,7 @@ contains
         m_MOK = int(m_glb + 1, MPI_OFFSET_KIND)
         n_MOK = int(n_glb + 1, MPI_OFFSET_KIND)
         p_MOK = int(p_glb + 1, MPI_OFFSET_KIND)
-        WP_MOK = int(storage_size(0)/8, MPI_OFFSET_KIND)
+        WP_MOK = int(storage_size(0._stp)/8, MPI_OFFSET_KIND)
         MOK = int(1._wp, MPI_OFFSET_KIND)
 
         write (file_loc, '(A)') 'ib.dat'