Add isFci for fields

include/bout/coordinates.hxx

@@ -133,9 +133,10 @@ public:
     transform = std::move(pt);
   }
 
+  bool hasParallelTransform() const { return transform != nullptr; }
   /// Return the parallel transform
-  ParallelTransform& getParallelTransform() {
-    ASSERT1(transform != nullptr);
+  ParallelTransform& getParallelTransform() const {
+    ASSERT1(hasParallelTransform());
     return *transform;
   }
 

include/bout/field.hxx

@@ -86,6 +86,8 @@ public:
 
   std::string name;
 
+  bool isFci() const;
+
 #if CHECK > 0
   // Routines to test guard/boundary cells set
 

include/bout/mesh.hxx

@@ -636,9 +636,22 @@ public:
     return inserted.first->second;
   }
 
+  std::shared_ptr<Coordinates>
+  getCoordinatesConst(const CELL_LOC location = CELL_CENTRE) const {
+    ASSERT1(location != CELL_DEFAULT);
+    ASSERT1(location != CELL_VSHIFT);
+
+    auto found = coords_map.find(location);
+    if (found != coords_map.end()) {
+      // True branch most common, returns immediately
+      return found->second;
+    }
+    throw BoutException("Coordinates not yet set. Use non-const version!");
+  }
+
   /// Returns the non-CELL_CENTRE location
   /// allowed as a staggered location
-  CELL_LOC getAllowedStaggerLoc(DIRECTION direction) const {
+  static CELL_LOC getAllowedStaggerLoc(DIRECTION direction) {
     AUTO_TRACE();
     switch (direction) {
     case (DIRECTION::X):
@@ -828,6 +841,16 @@ public:
     ASSERT1(RegionID.has_value());
     return region3D[RegionID.value()];
   }
+  bool isFci() const {
+    const auto coords = this->getCoordinatesConst();
+    if (coords == nullptr) {
+      return false;
+    }
+    if (not coords->hasParallelTransform()) {
+      return false;
+    }
+    return not coords->getParallelTransform().canToFromFieldAligned();
+  }
 
 private:
   /// Allocates default Coordinates objects
@@ -837,8 +860,7 @@ private:
   /// (useful if CELL_CENTRE Coordinates have been changed, so reading from file
   /// would not be correct).
   std::shared_ptr<Coordinates>
-  createDefaultCoordinates(const CELL_LOC location,
-                           bool force_interpolate_from_centre = false);
+  createDefaultCoordinates(CELL_LOC location, bool force_interpolate_from_centre = false);
 
   //Internal region related information
   std::map<std::string, size_t> regionMap3D;

src/field/field.cxx

@@ -39,3 +39,14 @@ int Field::getNx() const { return getMesh()->LocalNx; }
 int Field::getNy() const { return getMesh()->LocalNy; }
 
 int Field::getNz() const { return getMesh()->LocalNz; }
+
+bool Field::isFci() const {
+  const auto* coords = this->getCoordinates();
+  if (coords == nullptr) {
+    return false;
+  }
+  if (not coords->hasParallelTransform()) {
+    return false;
+  }
+  return not coords->getParallelTransform().canToFromFieldAligned();
+}