From 5dc07cfdc0d748cc39861f657fcff268eaf1ac1d Mon Sep 17 00:00:00 2001
From: Jan Malec <jan.malec@ijs.si>
Date: Wed, 16 Oct 2024 12:44:47 +0200
Subject: [PATCH] Fix path handeling for thermal ace generAtion

---
 openmc/data/njoy.py    | 28 +++++++++++++++++++++-------
 openmc/data/thermal.py | 14 +++++++++++---
 2 files changed, 32 insertions(+), 10 deletions(-)

diff --git a/openmc/data/njoy.py b/openmc/data/njoy.py
index 1bf44891ef4..c4de8874a90 100644
--- a/openmc/data/njoy.py
+++ b/openmc/data/njoy.py
@@ -400,7 +400,7 @@ def make_ace(filename, temperatures=None, acer=True, xsdir=None,
     if acer:
         ace = (output_dir / "ace") if acer is True else Path(acer)
         xsdir = (ace.parent / "xsdir") if xsdir is None else xsdir
-        with ace.open('w') as ace_file, xsdir.open('w') as xsdir_file:
+        with open(ace, 'w') as ace_file, open(xsdir, 'w') as xsdir_file:
             for temperature in temperatures:
                 # Get contents of ACE file
                 text = (output_dir / f"ace_{temperature:.1f}").read_text()
@@ -589,16 +589,30 @@ def make_ace_thermal(filename, filename_thermal, temperatures=None,
     commands += 'stop\n'
     run(commands, tapein, tapeout, **kwargs)
 
-    ace = output_dir / ace
+    # Determine the path for the final ACE and xsdir files
+    # If 'ace' is an absolute path, use it directly
+    # If 'ace' is a relative path, place it in the current directory
+    if not os.path.isabs(ace):
+        ace = os.path.abspath(ace)
+
+    # Determine xsdir path similarly
+    if xsdir is None:
+        xsdir = os.path.join(os.path.dirname(ace), 'xsdir')
+    else:
+        if not os.path.isabs(xsdir):
+            xsdir = os.path.abspath(xsdir)
+            
     xsdir = (ace.parent / "xsdir") if xsdir is None else Path(xsdir)
-    with ace.open('w') as ace_file, xsdir.open('w') as xsdir_file:
+    with open(ace, 'w') as ace_file, open(xsdir, 'w') as xsdir_file:
         # Concatenate ACE and xsdir files together
         for temperature in temperatures:
-            ace_in = output_dir / f"ace_{temperature:.1f}"
-            ace_file.write(ace_in.read_text())
+            ace_in = os.path.join(output_dir, f"ace_{temperature:.1f}")
+            with open(ace_in, 'r') as f:
+                ace_file.write(f.read())
 
-            xsdir_in = output_dir / f"xsdir_{temperature:.1f}"
-            xsdir_file.write(xsdir_in.read_text())
+            xsdir_in = os.path.join(output_dir, f"xsdir_{temperature:.1f}")
+            with open(xsdir_in, 'r') as f:
+                xsdir_file.write(f.read())
 
     # Remove ACE/xsdir files for each temperature
     for temperature in temperatures:
diff --git a/openmc/data/thermal.py b/openmc/data/thermal.py
index 6df171d3a4f..8ca80328cbb 100644
--- a/openmc/data/thermal.py
+++ b/openmc/data/thermal.py
@@ -839,13 +839,22 @@ def from_njoy(cls, filename, filename_thermal, temperatures=None,
         with tempfile.TemporaryDirectory() as tmpdir:
             # Run NJOY to create an ACE library
             kwargs.setdefault('output_dir', tmpdir)
-            kwargs.setdefault('ace', os.path.join(kwargs['output_dir'], 'ace'))
+
+            # Get the ace filename from kwargs or default to 'ace'
+            ace_filename = kwargs.get('ace', 'ace')
+            kwargs['ace'] = ace_filename
+
             kwargs['evaluation'] = evaluation
             kwargs['evaluation_thermal'] = evaluation_thermal
             make_ace_thermal(filename, filename_thermal, temperatures, **kwargs)
 
+            # Read the ACE file from the correct path
+            ace_path = kwargs['ace']
+            if not os.path.isabs(ace_path):
+                ace_path = os.path.abspath(ace_path)
+
+            lib = Library(ace_path)
             # Create instance from ACE tables within library
-            lib = Library(kwargs['ace'])
             name = kwargs.get('table_name')
             data = cls.from_ace(lib.tables[0], name=name)
             for table in lib.tables[1:]:
@@ -867,7 +876,6 @@ def from_njoy(cls, filename, filename_thermal, temperatures=None,
                         if isinstance(rx_endf.xs[t], (IncoherentElastic, Sum)):
                             rx.xs[t] = rx_endf.xs[t]
                             rx.distribution[t] = rx_endf.distribution[t]
-
         return data
 
     @classmethod