Merge pull request #1898 from paulromano/two-bug-fixes

Bug fixes for specifying Materials.cross_sections

openmc/material.py

@@ -935,14 +935,9 @@ class Material(IDManagerMixin):
             xml_elements.append(self._get_nuclide_xml(nuclide))
         return xml_elements
 
-    def to_xml_element(self, cross_sections=None):
+    def to_xml_element(self):
         """Return XML representation of the material
 
-        Parameters
-        ----------
-        cross_sections : str
-            Path to an XML cross sections listing file
-
         Returns
         -------
         element : xml.etree.ElementTree.Element
@@ -1092,7 +1087,7 @@ class Material(IDManagerMixin):
         new_density = np.sum([dens for dens in mass_per_cc.values()])
         new_mat.set_density('g/cm3', new_density)
 
-        # If any of the involved materials is depletable, the new material is 
+        # If any of the involved materials is depletable, the new material is
         # depletable
         new_mat.depletable = any(mat.depletable for mat in materials)
 
@@ -1173,7 +1168,10 @@ class Materials(cv.CheckedList):
     ----------
     materials : Iterable of openmc.Material
         Materials to add to the collection
-    cross_sections : str
+
+    Attributes
+    ----------
+    cross_sections : str or path-like
         Indicates the path to an XML cross section listing file (usually named
         cross_sections.xml). If it is not set, the
         :envvar:`OPENMC_CROSS_SECTIONS` environment variable will be used for
@@ -1196,8 +1194,8 @@ class Materials(cv.CheckedList):
 
     @cross_sections.setter
     def cross_sections(self, cross_sections):
-        cv.check_type('cross sections', cross_sections, str)
-        self._cross_sections = cross_sections
+        if cross_sections is not None:
+            self._cross_sections = Path(cross_sections)
 
     def append(self, material):
         """Append material to collection
@@ -1252,9 +1250,9 @@ class Materials(cv.CheckedList):
             fh.write('<materials>\n')
 
             # Write the <cross_sections> element.
-            if self._cross_sections is not None:
+            if self.cross_sections is not None:
                 element = ET.Element('cross_sections')
-                element.text = str(self._cross_sections)
+                element.text = str(self.cross_sections)
                 clean_indentation(element, level=1)
                 element.tail = element.tail.strip(' ')
                 fh.write('  ')
@@ -1263,7 +1261,7 @@ class Materials(cv.CheckedList):
 
             # Write the <material> elements.
             for material in sorted(self, key=lambda x: x.id):
-                element = material.to_xml_element(self.cross_sections)
+                element = material.to_xml_element()
                 clean_indentation(element, level=1)
                 element.tail = element.tail.strip(' ')
                 fh.write('  ')

src/cross_sections.cpp

@@ -76,8 +76,10 @@ Library::Library(pugi::xml_node node, const std::string& directory)
     path_ = path;
   } else if (ends_with(directory, "/")) {
     path_ = directory + path;
-  } else {
+  } else if (!directory.empty()) {
     path_ = directory + "/" + path;
+  } else {
+    path_ = path;
   }
 
   if (!file_exists(path_)) {
@@ -135,6 +137,13 @@ void read_cross_sections_xml()
     }
   } else {
     settings::path_cross_sections = get_node_value(root, "cross_sections");
+
+    // If no '/' found, the file is probably in the input directory
+    auto pos = settings::path_cross_sections.rfind("/");
+    if (pos == std::string::npos && !settings::path_input.empty()) {
+      settings::path_cross_sections =
+        settings::path_input + "/" + settings::path_cross_sections;
+    }
   }
 
   // Now that the cross_sections.xml or mgxs.h5 has been located, read it in
@@ -295,10 +304,12 @@ void read_ce_cross_sections_xml()
     // TODO: Use std::filesystem functionality when C++17 is adopted
     auto pos = filename.rfind("/");
     if (pos == std::string::npos) {
-      // no '/' found, probably a Windows directory
-      pos = filename.rfind("\\");
+      // No '\\' found, so the file must be in the same directory as
+      // materials.xml
+      directory = settings::path_input;
+    } else {
+      directory = filename.substr(0, pos);
     }
-    directory = filename.substr(0, pos);
   }
 
   for (const auto& node_library : root.children("library")) {

tests/regression_tests/mg_convert/inputs_true.dat

@@ -8,7 +8,7 @@
 </geometry>
 <?xml version='1.0' encoding='utf-8'?>
 <materials>
-  <cross_sections>./mgxs.h5</cross_sections>
+  <cross_sections>mgxs.h5</cross_sections>
   <material id="1" name="UO2 fuel">
     <density units="macro" value="1.1" />
     <macroscopic name="UO2" />