API changes: Field and FieldSet

docs/examples/example_nemo_curvilinear.py

@@ -108,7 +108,7 @@ def test_nemo_3D_samegrid():
 
     fieldset = parcels.FieldSet.from_nemo(filenames, variables, dimensions)
 
-    assert fieldset.U.dataFiles is not fieldset.W.dataFiles
+    assert fieldset.U._dataFiles is not fieldset.W._dataFiles
 
 
 def main(args=None):

parcels/_typing.py

@@ -10,7 +10,7 @@
 import datetime
 import os
 from collections.abc import Callable
-from typing import Literal
+from typing import Any, Literal, get_args
 
 
 class ParcelsAST(ast.AST):
@@ -37,10 +37,33 @@ class ParcelsAST(ast.AST):
 Mesh = Literal["spherical", "flat"]  # corresponds with `mesh`
 VectorType = Literal["3D", "2D"] | None  # corresponds with `vector_type`
 ChunkMode = Literal["auto", "specific", "failsafe"]  # corresponds with `chunk_mode`
-GridIndexingType = Literal["pop", "mom5", "mitgcm", "nemo"]  # corresponds with `grid_indexing_type`
+GridIndexingType = Literal["pop", "mom5", "mitgcm", "nemo"]  # corresponds with `gridindexingtype`
 UpdateStatus = Literal["not_updated", "first_updated", "updated"]  # corresponds with `update_status`
 TimePeriodic = float | datetime.timedelta | Literal[False]  # corresponds with `update_status`
 NetcdfEngine = Literal["netcdf4", "xarray", "scipy"]
 
 
 KernelFunction = Callable[..., None]
+
+
+def _validate_against_pure_literal(value, typing_literal):
+    """Uses a Literal type alias to validate.
+
+    Can't be used with ``Literal[...] | None`` etc. as its not a pure literal.
+    """
+    if value not in get_args(typing_literal):
+        msg = f"Invalid value {value!r}. Valid options are {get_args(typing_literal)!r}"
+        raise ValueError(msg)
+
+
+# Assertion functions to clean user input
+def assert_valid_interp_method(value: Any):
+    _validate_against_pure_literal(value, InterpMethodOption)
+
+
+def assert_valid_mesh(value: Any):
+    _validate_against_pure_literal(value, Mesh)
+
+
+def assert_valid_gridindexingtype(value: Any):
+    _validate_against_pure_literal(value, GridIndexingType)

parcels/application_kernels/advection.py

@@ -125,14 +125,14 @@
     direction = 1.0 if particle.dt > 0 else -1.0
     withW = True if "W" in [f.name for f in fieldset.get_fields()] else False
     withTime = True if len(fieldset.U.grid.time_full) > 1 else False
-    ti = fieldset.U.time_index(time)[0]
+    ti = fieldset.U._time_index(time)[0]
     ds_t = particle.dt
     if withTime:
         tau = (time - fieldset.U.grid.time[ti]) / (fieldset.U.grid.time[ti + 1] - fieldset.U.grid.time[ti])
         time_i = np.linspace(0, fieldset.U.grid.time[ti + 1] - fieldset.U.grid.time[ti], I_s)
         ds_t = min(ds_t, time_i[np.where(time - fieldset.U.grid.time[ti] < time_i)[0][0]])
 
-    xsi, eta, zeta, xi, yi, zi = fieldset.U.search_indices(
+    xsi, eta, zeta, xi, yi, zi = fieldset.U._search_indices(
         particle.lon, particle.lat, particle.depth, particle=particle
     )
     if withW:

parcels/compilation/codegenerator.py

@@ -819,14 +819,14 @@
         self.visit(node.field)
         self.visit(node.args)
         args = self._check_FieldSamplingArguments(node.args.ccode)
-        ccode_eval = node.field.obj.ccode_eval(node.var, *args)
+        ccode_eval = node.field.obj._ccode_eval(node.var, *args)
         stmts = [
             c.Assign("parcels_interp_state", ccode_eval),
             c.Assign("particles->state[pnum]", "max(particles->state[pnum], parcels_interp_state)"),
         ]
 
         if node.convert:
-            ccode_conv = node.field.obj.ccode_convert(*args)
+            ccode_conv = node.field.obj._ccode_convert(*args)
             conv_stat = c.Statement(f"{node.var} *= {ccode_conv}")
             stmts += [conv_stat]
 
@@ -836,17 +836,17 @@
         self.visit(node.field)
         self.visit(node.args)
         args = self._check_FieldSamplingArguments(node.args.ccode)
-        ccode_eval = node.field.obj.ccode_eval(
+        ccode_eval = node.field.obj._ccode_eval(
             node.var, node.var2, node.var3, node.field.obj.U, node.field.obj.V, node.field.obj.W, *args
         )
         if node.convert and node.field.obj.U.interp_method != "cgrid_velocity":
-            ccode_conv1 = node.field.obj.U.ccode_convert(*args)
-            ccode_conv2 = node.field.obj.V.ccode_convert(*args)
+            ccode_conv1 = node.field.obj.U._ccode_convert(*args)
+            ccode_conv2 = node.field.obj.V._ccode_convert(*args)
             statements = [c.Statement(f"{node.var} *= {ccode_conv1}"), c.Statement(f"{node.var2} *= {ccode_conv2}")]
         else:
             statements = []
         if node.convert and node.field.obj.vector_type == "3D":
-            ccode_conv3 = node.field.obj.W.ccode_convert(*args)
+            ccode_conv3 = node.field.obj.W._ccode_convert(*args)
             statements.append(c.Statement(f"{node.var3} *= {ccode_conv3}"))
         conv_stat = c.Block(statements)
         node.ccode = c.Block(
@@ -864,8 +864,8 @@
         cstat = []
         args = self._check_FieldSamplingArguments(node.args.ccode)
         for fld in node.fields.obj:
-            ccode_eval = fld.ccode_eval(node.var, *args)
-            ccode_conv = fld.ccode_convert(*args)
+            ccode_eval = fld._ccode_eval(node.var, *args)
+            ccode_conv = fld._ccode_convert(*args)
             conv_stat = c.Statement(f"{node.var} *= {ccode_conv}")
             cstat += [
                 c.Assign("particles->state[pnum]", ccode_eval),
@@ -884,15 +884,15 @@
         cstat = []
         args = self._check_FieldSamplingArguments(node.args.ccode)
         for fld in node.fields.obj:
-            ccode_eval = fld.ccode_eval(node.var, node.var2, node.var3, fld.U, fld.V, fld.W, *args)
+            ccode_eval = fld._ccode_eval(node.var, node.var2, node.var3, fld.U, fld.V, fld.W, *args)
             if fld.U.interp_method != "cgrid_velocity":
-                ccode_conv1 = fld.U.ccode_convert(*args)
-                ccode_conv2 = fld.V.ccode_convert(*args)
+                ccode_conv1 = fld.U._ccode_convert(*args)
+                ccode_conv2 = fld.V._ccode_convert(*args)
                 statements = [c.Statement(f"{node.var} *= {ccode_conv1}"), c.Statement(f"{node.var2} *= {ccode_conv2}")]
             else:
                 statements = []
             if fld.vector_type == "3D":
-                ccode_conv3 = fld.W.ccode_convert(*args)
+                ccode_conv3 = fld.W._ccode_convert(*args)
                 statements.append(c.Statement(f"{node.var3} *= {ccode_conv3}"))
             cstat += [
                 c.Assign("particles->state[pnum]", ccode_eval),