Merge branch '37-hdf5-geometry-views' into 26-mpi-geometry-objects

.gitattributes

@@ -1 +1,4 @@
 tools/Jupyter_notebooks/* linguist-vendored
+reframe_tests/regression_checks/TestGeometryView_5176823e/partial_volume.vtkhdf filter=lfs diff=lfs merge=lfs -text
+reframe_tests/regression_checks/TestGeometryView_5176823e/full_volume.vtkhdf filter=lfs diff=lfs merge=lfs -text
+reframe_tests/regression_checks/TestGeometryView_77980202/full_volume.vtkhdf filter=lfs diff=lfs merge=lfs -text

gprMax/cmds_singleuse.py

@@ -92,7 +92,7 @@ class Discretisation(UserObjectSingle):
 
     def build(self, model, uip):
         try:
-            model.dl = np.array(self.kwargs["p1"], dtype=float)
+            model.dl = np.array(self.kwargs["p1"], dtype=np.float64)
         except KeyError:
             logger.exception(f"{self.__str__()} discretisation requires a point")
             raise

gprMax/cython/geometry_outputs.pyx

@@ -17,9 +17,81 @@
 # along with gprMax.  If not, see <http://www.gnu.org/licenses/>.
 
 import numpy as np
+
 cimport numpy as np
 
 
+cpdef get_line_properties(
+    int number_of_lines,
+    int nx,
+    int ny,
+    int nz,
+    np.uint32_t[:, :, :, :] ID
+):
+    """Generate connectivity array and get material ID for each line.
+
+    Args:
+        number_of_lines: Number of lines.
+        nx: Number of points in the x dimension.
+        ny: Number of points in the y dimension.
+        nz: Number of points in the z dimension.
+        ID: memoryview of sampled ID array according to geometry view
+            spatial discretisation.
+
+    Returns:
+        connectivity: NDArray of shape (2 * number_of_lines,) listing
+            the start and end point IDs of each line.
+        material_data: NDArray of shape (number_of_lines,) listing
+            material IDs for each line.
+    """
+    cdef np.ndarray material_data = np.zeros(number_of_lines, dtype=np.uint32)
+    cdef np.ndarray connectivity = np.zeros(2 * number_of_lines, dtype=np.intc)
+    cdef int line_index = 0
+    cdef int connectivity_index = 0
+    cdef int point_id = 0
+
+    cdef int z_step = 1
+    cdef int y_step = nz + 1
+    cdef int x_step = y_step * (ny + 1)
+
+    cdef int i, j, k
+
+    for i in range(nx):
+        for j in range(ny):
+            for k in range(nz):
+
+                # x-direction cell edge
+                material_data[line_index] = ID[0, i, j, k]
+                connectivity[connectivity_index] = point_id
+                connectivity[connectivity_index + 1] = point_id + x_step
+                line_index += 1
+                connectivity_index += 2
+
+                # y-direction cell edge
+                material_data[line_index] = ID[1, i, j, k]
+                connectivity[connectivity_index] = point_id
+                connectivity[connectivity_index + 1] = point_id + y_step
+                line_index += 1
+                connectivity_index += 2
+
+                # z-direction cell edge
+                material_data[line_index] = ID[2, i, j, k]
+                connectivity[connectivity_index] = point_id
+                connectivity[connectivity_index + 1] = point_id + z_step
+                line_index += 1
+                connectivity_index += 2
+
+                # Next point
+                point_id += 1
+
+            # Skip point at (i, j, nz)
+            point_id += 1
+
+        # Skip points in line (i, ny, t) where 0 <= t <= nz
+        point_id += nz + 1
+
+    return connectivity, material_data
+
 cpdef write_lines(
     float xs,
     float ys,

gprMax/geometry_outputs.py

@@ -16,34 +16,38 @@
 # You should have received a copy of the GNU General Public License
 # along with gprMax.  If not, see <http://www.gnu.org/licenses/>.
 
-import json
 import logging
 import sys
+from abc import ABC, abstractmethod
 from io import TextIOWrapper
 from itertools import chain
 from pathlib import Path
+from typing import Dict, List, Sequence, Tuple, Union
 
 import h5py
 import numpy as np
-from evtk.hl import imageToVTK, linesToVTK
-from evtk.vtk import VtkGroup, VtkImageData, VtkUnstructuredGrid
-from mpi4py import MPI
+import numpy.typing as npt
 from tqdm import tqdm
 
 import gprMax.config as config
 from gprMax.grid.fdtd_grid import FDTDGrid
 from gprMax.grid.mpi_grid import MPIGrid
 from gprMax.materials import Material
+from gprMax.receivers import Rx
+from gprMax.sources import Source
+from gprMax.vtkhdf_filehandlers.vtk_image_data import VtkImageData
+from gprMax.vtkhdf_filehandlers.vtk_unstructured_grid import VtkUnstructuredGrid
+from gprMax.vtkhdf_filehandlers.vtkhdf import VtkCellType, VtkHdfFile
 
 from ._version import __version__
-from .cython.geometry_outputs import write_lines
+from .cython.geometry_outputs import get_line_properties
 from .subgrids.grid import SubGridBaseGrid
 from .utilities.utilities import get_terminal_width
 
 logger = logging.getLogger(__name__)
 
 
-def save_geometry_views(gvs):
+def save_geometry_views(gvs: "List[GeometryView]"):
     """Creates and saves geometryviews.
 
     Args:
@@ -53,28 +57,42 @@ def save_geometry_views(gvs):
     logger.info("")
     for i, gv in enumerate(gvs):
         gv.set_filename()
-        vtk_data = gv.prep_vtk()
+        gv.prep_vtk()
         pbar = tqdm(
             total=gv.nbytes,
             unit="byte",
             unit_scale=True,
-            desc=f"Writing geometry view file {i + 1}/{len(gvs)}, "
-            f"{gv.filename.name}{gv.vtkfiletype.ext}",
+            desc=f"Writing geometry view file {i + 1}/{len(gvs)}, {gv.filename.name}",
             ncols=get_terminal_width() - 1,
             file=sys.stdout,
             disable=not config.sim_config.general["progressbars"],
         )
-        gv.write_vtk(vtk_data)
+        gv.write_vtk()
         pbar.update(gv.nbytes)
         pbar.close()
 
     logger.info("")
 
 
-class GeometryView:
+class GeometryView(ABC):
     """Base class for Geometry Views."""
 
-    def __init__(self, xs, ys, zs, xf, yf, zf, dx, dy, dz, filename, grid):
+    FILE_EXTENSION = ".vtkhdf"
+
+    def __init__(
+        self,
+        xs: int,
+        ys: int,
+        zs: int,
+        xf: int,
+        yf: int,
+        zf: int,
+        dx: int,
+        dy: int,
+        dz: int,
+        filename: str,
+        grid: FDTDGrid,
+    ):
         """
         Args:
             xs, xf, ys, yf, zs, zf: ints for extent of geometry view in cells.
@@ -83,44 +101,89 @@ class GeometryView:
             grid: FDTDGrid class describing a grid in a model.
         """
 
-        self.xs = xs
-        self.ys = ys
-        self.zs = zs
-        self.xf = xf
-        self.yf = yf
-        self.zf = zf
-        self.nx = self.xf - self.xs
-        self.ny = self.yf - self.ys
-        self.nz = self.zf - self.zs
-        self.dx = dx
-        self.dy = dy
-        self.dz = dz
-        self.filename = filename
+        self.start = np.array([xs, ys, zs], dtype=np.intc)
+        self.stop = np.array([xf, yf, zf], dtype=np.intc)
+        self.step = np.array([dx, dy, dz], dtype=np.intc)
+        self.size = (self.stop - self.start) // self.step
+
+        self.filename = Path(filename)
         self.filenamebase = filename
         self.grid = grid
         self.nbytes = None
 
+        self.material_data = None
+        self.materials = None
+
+    # Properties for backwards compatibility
+    @property
+    def xs(self) -> int:
+        return self.start[0]
+
+    @property
+    def ys(self) -> int:
+        return self.start[1]
+
+    @property
+    def zs(self) -> int:
+        return self.start[2]
+
+    @property
+    def xf(self) -> int:
+        return self.stop[0]
+
+    @property
+    def yf(self) -> int:
+        return self.stop[1]
+
+    @property
+    def zf(self) -> int:
+        return self.stop[2]
+
+    @property
+    def dx(self) -> int:
+        return self.step[0]
+
+    @property
+    def dy(self) -> int:
+        return self.step[1]
+
+    @property
+    def dz(self) -> int:
+        return self.step[2]
+
+    @property
+    def nx(self) -> int:
+        return self.size[0]
+
+    @property
+    def ny(self) -> int:
+        return self.size[1]
+
+    @property
+    def nz(self) -> int:
+        return self.size[2]
+
     def set_filename(self):
-        """Constructs filename from user-supplied name and model run number."""
+        """Construct filename from user-supplied name and model number."""
         parts = config.get_model_config().output_file_path.parts
         self.filename = Path(
             *parts[:-1], self.filenamebase + config.get_model_config().appendmodelnumber
-        )
+        ).with_suffix(self.FILE_EXTENSION)
+
+    @abstractmethod
+    def prep_vtk(self):
+        pass
+
+    @abstractmethod
+    def write_vtk(self):
+        pass
 
 
 class GeometryViewLines(GeometryView):
-    """Unstructured grid (.vtu) for a per-cell-edge geometry view."""
-
-    def __init__(self, *args):
-        super().__init__(*args)
-        self.vtkfiletype = VtkUnstructuredGrid
+    """Unstructured grid for a per-cell-edge geometry view."""
 
     def prep_vtk(self):
-        """Prepares data for writing to VTK file.
-
-        Returns:
-            vtk_data: dict of coordinates, data, and comments for VTK file.
-        """
+        """Prepares data for writing to VTKHDF file."""
 
         # Sample ID array according to geometry view spatial discretisation
         # Only create a new array if subsampling is required
@@ -129,7 +192,7 @@ class GeometryViewLines(GeometryView):
             or (self.dx, self.dy, self.dz) != (1, 1, 1)
             or (self.xs, self.ys, self.zs) != (0, 0, 0)
         ):
-            # Require contiguous for evtk library
+            # Require contiguous array
             ID = np.ascontiguousarray(
                 self.grid.ID[
                     :,
@@ -142,81 +205,66 @@ class GeometryViewLines(GeometryView):
             # This array is contiguous by design
             ID = self.grid.ID
 
-        x, y, z, lines = write_lines(
-            (self.xs * self.grid.dx),
-            (self.ys * self.grid.dy),
-            (self.zs * self.grid.dz),
-            self.nx,
-            self.ny,
-            self.nz,
-            (self.dx * self.grid.dx),
-            (self.dy * self.grid.dy),
-            (self.dz * self.grid.dz),
-            ID,
-        )
+        x = np.arange(self.nx + 1, dtype=np.float64)
+        y = np.arange(self.ny + 1, dtype=np.float64)
+        z = np.arange(self.nz + 1, dtype=np.float64)
+        coords = np.meshgrid(x, y, z, indexing="ij")
+        self.points = np.vstack(list(map(np.ravel, coords))).T
+        self.points += self.start
+        self.points *= self.step * self.grid.dl
 
         # Add offset to subgrid geometry to correctly locate within main grid
         if isinstance(self.grid, SubGridBaseGrid):
-            x += self.grid.i0 * self.grid.dx * self.grid.ratio
-            y += self.grid.j0 * self.grid.dy * self.grid.ratio
-            z += self.grid.k0 * self.grid.dz * self.grid.ratio
+            offset = [self.grid.i0, self.grid.j0, self.grid.k0]
+            self.points += offset * self.grid.dl * self.grid.ratio
+
+        # Each point is the 'source' for 3 lines.
+        # NB: Excluding points at the far edge of the geometry as those
+        # are the 'source' for no lines
+        n_lines = 3 * self.nx * self.ny * self.nz
+
+        self.cell_types = np.full(n_lines, VtkCellType.LINE)
+        self.cell_offsets = np.arange(0, 2 * n_lines + 2, 2, dtype=np.intc)
+
+        self.connectivity, self.material_data = get_line_properties(
+            n_lines, self.nx, self.ny, self.nz, ID
+        )
+
+        assert isinstance(self.connectivity, np.ndarray)
+        assert isinstance(self.material_data, np.ndarray)
 
         # Write information about any PMLs, sources, receivers
-        comments = Comments(self.grid, self)
-        comments.averaged_materials = True
-        comments.materials_only = True
-        info = comments.get_gprmax_info()
-        comments = json.dumps(info)
+        self.metadata = Metadata(self.grid, self, averaged_materials=True, materials_only=True)
 
         # Number of bytes of data to be written to file
-        offsets_size = np.arange(start=2, step=2, stop=len(x) + 1, dtype="int32").nbytes
-        connect_size = len(x) * np.dtype("int32").itemsize
-        cell_type_size = len(x) * np.dtype("uint8").itemsize
         self.nbytes = (
-            x.nbytes
-            + y.nbytes
-            + z.nbytes
-            + lines.nbytes
-            + offsets_size
-            + connect_size
-            + cell_type_size
+            self.points.nbytes
+            + self.cell_types.nbytes
+            + self.connectivity.nbytes
+            + self.cell_offsets.nbytes
+            + self.material_data.nbytes
         )
 
-        vtk_data = {"x": x, "y": y, "z": z, "data": lines, "comments": comments}
+    def write_vtk(self):
+        """Writes geometry information to a VTKHDF file."""
 
-        return vtk_data
-
-    def write_vtk(self, vtk_data):
-        """Writes geometry information to a VTK file.
-
-        Args:
-            vtk_data: dict of coordinates, data, and comments for VTK file.
-        """
-
-        # Write the VTK file .vtu
-        linesToVTK(
-            str(self.filename),
-            vtk_data["x"],
-            vtk_data["y"],
-            vtk_data["z"],
-            cellData={"Material": vtk_data["data"]},
-            comments=[vtk_data["comments"]],
-        )
+        # Write the VTK file
+        with VtkUnstructuredGrid(
+            self.filename,
+            self.points,
+            self.cell_types,
+            self.connectivity,
+            self.cell_offsets,
+        ) as f:
+            f.add_cell_data("Material", self.material_data)
+            self.metadata.write_to_vtkhdf(f)
 
 
 class GeometryViewVoxels(GeometryView):
-    """Imagedata (.vti) for a per-cell geometry view."""
-
-    def __init__(self, *args):
-        super().__init__(*args)
-        self.vtkfiletype = VtkImageData
+    """Image data for a per-cell geometry view."""
 
     def prep_vtk(self):
-        """Prepares data for writing to VTK file.
-
-        Returns:
-            vtk_data: dict of data and comments for VTK file.
-        """
+        """Prepares data for writing to VTKHDF file."""
 
         # Sample solid array according to geometry view spatial discretisation
         # Only create a new array if subsampling is required
@@ -225,8 +273,8 @@ class GeometryViewVoxels(GeometryView):
             or (self.dx, self.dy, self.dz) != (1, 1, 1)
             or (self.xs, self.ys, self.zs) != (0, 0, 0)
         ):
-            # Require contiguous for evtk library
-            solid = np.ascontiguousarray(
+            # Require contiguous array
+            self.material_data = np.ascontiguousarray(
                 self.grid.solid[
                     self.xs : self.xf : self.dx,
                     self.ys : self.yf : self.dy,
@@ -235,74 +283,64 @@ class GeometryViewVoxels(GeometryView):
             )
         else:
             # This array is contiguous by design
-            solid = self.grid.solid
-
-        # Write information about any PMLs, sources, receivers
-        comments = Comments(self.grid, self)
-        info = comments.get_gprmax_info()
-        comments = json.dumps(info)
-
-        self.nbytes = solid.nbytes
-
-        vtk_data = {"data": solid, "comments": comments}
-
-        return vtk_data
-
-    def write_vtk(self, vtk_data):
-        """Writes geometry information to a VTK file.
-
-        Args:
-            vtk_data: dict of data and comments for VTK file.
-        """
+            self.material_data = self.grid.solid
 
         if isinstance(self.grid, SubGridBaseGrid):
-            origin = (
+            self.origin = np.array(
+                [
                     (self.grid.i0 * self.grid.dx * self.grid.ratio),
                     (self.grid.j0 * self.grid.dy * self.grid.ratio),
                     (self.grid.k0 * self.grid.dz * self.grid.ratio),
+                ]
             )
         else:
-            origin = ((self.xs * self.grid.dx), (self.ys * self.grid.dy), (self.zs * self.grid.dz))
+            self.origin = self.start * self.grid.dl
 
-        # Write the VTK file .vti
-        imageToVTK(
-            str(self.filename),
-            origin=origin,
-            spacing=((self.dx * self.grid.dx), (self.dy * self.grid.dy), (self.dz * self.grid.dz)),
-            cellData={"Material": vtk_data["data"]},
-            comments=[vtk_data["comments"]],
-        )
+        self.spacing = self.step * self.grid.dl
+
+        # Write information about any PMLs, sources, receivers
+        self.metadata = Metadata(self.grid, self)
+
+        self.nbytes = self.material_data.nbytes
+
+    def write_vtk(self):
+        """Writes geometry information to a VTKHDF file."""
+
+        with VtkImageData(self.filename, self.size, self.origin, self.spacing) as f:
+            f.add_cell_data("Material", self.material_data)
+            self.metadata.write_to_vtkhdf(f)
 
 
-class Comments:
+class Metadata:
     """Comments can be strings included in the header of XML VTK file, and are
     used to hold extra (gprMax) information about the VTK data.
     """
 
-    def __init__(self, grid, gv):
+    def __init__(
+        self,
+        grid: FDTDGrid,
+        gv: GeometryView,
+        averaged_materials: bool = False,
+        materials_only: bool = False,
+    ):
         self.grid = grid
         self.gv = gv
-        self.averaged_materials = False
-        self.materials_only = False
+        self.averaged_materials = averaged_materials
+        self.materials_only = materials_only
 
-    def get_gprmax_info(self):
-        """Returns gprMax specific information relating material, source,
-        and receiver names to numeric identifiers.
-        """
+        self.gprmax_version = __version__
+        self.dx_dy_dz = self.grid.dl
+        self.nx_ny_nz = np.array([self.grid.nx, self.grid.ny, self.grid.nz], dtype=np.intc)
 
-        # Comments for Paraview macro
-        comments = {
-            "gprMax_version": __version__,
-            "dx_dy_dz": self.dx_dy_dz_comment(),
-            "nx_ny_nz": self.nx_ny_nz_comment(),
-            "Materials": self.materials_comment(),
-        }  # Write the name and numeric ID for each material
+        self.materials = self.materials_comment()
 
         # Write information on PMLs, sources, and receivers
         if not self.materials_only:
             # Information on PML thickness
             if self.grid.pmls["slabs"]:
-                comments["PMLthickness"] = self.pml_gv_comment()
+                self.pml_thickness = self.pml_gv_comment()
+            else:
+                self.pml_thickness = None
             srcs = (
                 self.grid.hertziandipoles
                 + self.grid.magneticdipoles
@@ -310,53 +348,89 @@ class Comments:
                 + self.grid.transmissionlines
             )
             if srcs:
-                comments["Sources"] = self.srcs_rx_gv_comment(srcs)
+                self.source_ids, self.source_positions = self.srcs_rx_gv_comment(srcs)
+            else:
+                self.source_ids = None
+                self.source_positions = None
             if self.grid.rxs:
-                comments["Receivers"] = self.srcs_rx_gv_comment(self.grid.rxs)
+                self.receiver_ids, self.receiver_positions = self.srcs_rx_gv_comment(self.grid.rxs)
+            else:
+                self.receiver_ids = None
+                self.receiver_positions = None
 
-        return comments
+    def write_to_vtkhdf(self, file_handler: VtkHdfFile):
+        file_handler.add_field_data(
+            "gprMax_version",
+            self.gprmax_version,
+            dtype=h5py.string_dtype(),
+        )
+        file_handler.add_field_data("dx_dy_dz", self.dx_dy_dz)
+        file_handler.add_field_data("nx_ny_nz", self.nx_ny_nz)
 
-    def pml_gv_comment(self):
+        file_handler.add_field_data(
+            "material_ids",
+            self.materials,
+            dtype=h5py.string_dtype(),
+        )
+
+        if not self.materials_only:
+            if self.pml_thickness is not None:
+                file_handler.add_field_data("pml_thickness", self.pml_thickness)
+
+            if self.source_ids is not None and self.source_positions is not None:
+                file_handler.add_field_data(
+                    "source_ids", self.source_ids, dtype=h5py.string_dtype()
+                )
+                file_handler.add_field_data("sources", self.source_positions)
+
+            if self.receiver_ids is not None and self.receiver_positions is not None:
+                file_handler.add_field_data(
+                    "receiver_ids", self.receiver_ids, dtype=h5py.string_dtype()
+                )
+                file_handler.add_field_data("receivers", self.receiver_positions)
+
+    def pml_gv_comment(self) -> List[int]:
         grid = self.grid
 
         # Only render PMLs if they are in the geometry view
-        pmlstorender = dict.fromkeys(grid.pmls["thickness"], 0)
+        thickness: Dict[str, int] = grid.pmls["thickness"]
+        gv_pml_depth = dict.fromkeys(thickness, 0)
 
-        # Casting to int required as json does not handle numpy types
-        if grid.pmls["thickness"]["x0"] - self.gv.xs > 0:
-            pmlstorender["x0"] = int(grid.pmls["thickness"]["x0"] - self.gv.xs)
-        if grid.pmls["thickness"]["y0"] - self.gv.ys > 0:
-            pmlstorender["y0"] = int(grid.pmls["thickness"]["y0"] - self.gv.ys)
-        if grid.pmls["thickness"]["z0"] - self.gv.zs > 0:
-            pmlstorender["z0"] = int(grid.pmls["thickness"]["z0"] - self.gv.zs)
-        if self.gv.xf > grid.nx - grid.pmls["thickness"]["xmax"]:
-            pmlstorender["xmax"] = int(self.gv.xf - (grid.nx - grid.pmls["thickness"]["xmax"]))
-        if self.gv.yf > grid.ny - grid.pmls["thickness"]["ymax"]:
-            pmlstorender["ymax"] = int(self.gv.yf - (grid.ny - grid.pmls["thickness"]["ymax"]))
-        if self.gv.zf > grid.nz - grid.pmls["thickness"]["zmax"]:
-            pmlstorender["zmax"] = int(self.gv.zf - (grid.nz - grid.pmls["thickness"]["zmax"]))
+        if self.gv.xs < thickness["x0"]:
+            gv_pml_depth["x0"] = thickness["x0"] - self.gv.xs
+        if self.gv.ys < thickness["y0"]:
+            gv_pml_depth["y0"] = thickness["y0"] - self.gv.ys
+        if thickness["z0"] - self.gv.zs > 0:
+            gv_pml_depth["z0"] = thickness["z0"] - self.gv.zs
+        if self.gv.xf > grid.nx - thickness["xmax"]:
+            gv_pml_depth["xmax"] = self.gv.xf - (grid.nx - thickness["xmax"])
+        if self.gv.yf > grid.ny - thickness["ymax"]:
+            gv_pml_depth["ymax"] = self.gv.yf - (grid.ny - thickness["ymax"])
+        if self.gv.zf > grid.nz - thickness["zmax"]:
+            gv_pml_depth["zmax"] = self.gv.zf - (grid.nz - thickness["zmax"])
 
-        return list(pmlstorender.values())
+        return list(gv_pml_depth.values())
 
-    def srcs_rx_gv_comment(self, srcs):
+    def srcs_rx_gv_comment(
+        self, srcs: Union[Sequence[Source], List[Rx]]
+    ) -> Tuple[List[str], npt.NDArray[np.float32]]:
         """Used to name sources and/or receivers."""
-        sc = []
-        for src in srcs:
-            p = (src.xcoord * self.grid.dx, src.ycoord * self.grid.dy, src.zcoord * self.grid.dz)
-            p = list(map(float, p))
+        names: List[str] = []
+        positions: npt.NDArray[np.float32] = np.empty((len(srcs), 3))
+        for index, src in enumerate(srcs):
+            position = src.coord * self.grid.dl
+            names.append(src.ID)
+            positions[index] = position
 
-            s = {"name": src.ID, "position": p}
-            sc.append(s)
+        return names, positions
 
-        return sc
+    def dx_dy_dz_comment(self) -> npt.NDArray[np.float64]:
+        return self.grid.dl
 
-    def dx_dy_dz_comment(self):
-        return list(map(float, [self.grid.dx, self.grid.dy, self.grid.dz]))
+    def nx_ny_nz_comment(self) -> npt.NDArray[np.intc]:
+        return np.array([self.grid.nx, self.grid.ny, self.grid.nz], dtype=np.intc)
 
-    def nx_ny_nz_comment(self):
-        return list(map(int, [self.grid.nx, self.grid.ny, self.grid.nz]))
-
-    def materials_comment(self):
+    def materials_comment(self) -> List[str]:
         if not self.averaged_materials:
             return [m.ID for m in self.grid.materials if m.type != "dielectric-smoothed"]
         else:

gprMax/grid/fdtd_grid.py

@@ -58,21 +58,21 @@ class FDTDGrid:
         self.nx = 0
         self.ny = 0
         self.nz = 0
-        self.dl = np.ones(3, dtype=float)
+        self.dl = np.ones(3, dtype=np.float64)
         self.dt = 0.0
 
         # Field Arrays
-        self.Ex: npt.NDArray[np.single]
-        self.Ey: npt.NDArray[np.single]
-        self.Ez: npt.NDArray[np.single]
-        self.Hx: npt.NDArray[np.single]
-        self.Hy: npt.NDArray[np.single]
-        self.Hz: npt.NDArray[np.single]
+        self.Ex: npt.NDArray[np.float32]
+        self.Ey: npt.NDArray[np.float32]
+        self.Ez: npt.NDArray[np.float32]
+        self.Hx: npt.NDArray[np.float32]
+        self.Hy: npt.NDArray[np.float32]
+        self.Hz: npt.NDArray[np.float32]
 
         # Dispersive Arrays
-        self.Tx: npt.NDArray[np.single]
-        self.Ty: npt.NDArray[np.single]
-        self.Tz: npt.NDArray[np.single]
+        self.Tx: npt.NDArray[np.float32]
+        self.Ty: npt.NDArray[np.float32]
+        self.Tz: npt.NDArray[np.float32]
 
         # Geometry Arrays
         self.solid: npt.NDArray[np.uint32]
@@ -81,9 +81,9 @@ class FDTDGrid:
         self.ID: npt.NDArray[np.uint32]
 
         # Update Coefficient Arrays
-        self.updatecoeffsE: npt.NDArray
-        self.updatecoeffsH: npt.NDArray
-        self.updatecoeffsdispersive: npt.NDArray
+        self.updatecoeffsE: npt.NDArray[np.float32]
+        self.updatecoeffsH: npt.NDArray[np.float32]
+        self.updatecoeffsdispersive: npt.NDArray[np.float32]
 
         # PML parameters - set some defaults to use if not user provided
         self.pmls = {}

gprMax/materials.py

@@ -30,7 +30,7 @@ class Material:
     their properties and update coefficients.
     """
 
-    def __init__(self, numID, ID):
+    def __init__(self, numID: int, ID: str):
         """
         Args:
             numID: int for numeric I of the material.

gprMax/model.py

@@ -23,6 +23,7 @@ from typing import List, Sequence
 
 import humanize
 import numpy as np
+import numpy.typing as npt
 import psutil
 from colorama import Fore, Style, init
 
@@ -125,11 +126,11 @@ class Model:
         self.G.dl[2] = value
 
     @property
-    def dl(self) -> np.ndarray:
+    def dl(self) -> npt.NDArray[np.float64]:
         return self.G.dl
 
     @dl.setter
-    def dl(self, value: np.ndarray):
+    def dl(self, value: npt.NDArray[np.float64]):
         self.G.dl = value
 
     @property
@@ -164,7 +165,10 @@ class Model:
         self.p = psutil.Process()
 
         # Normal model reading/building process; bypassed if geometry information to be reused
-        self.reuse_geometry() if config.get_model_config().reuse_geometry() else self.build_geometry()
+        if config.get_model_config().reuse_geometry():
+            self.reuse_geometry()
+        else:
+            self.build_geometry()
 
         logger.info(
             f"Output directory: {config.get_model_config().output_file_path.parent.resolve()}\n"

gprMax/snapshots.py

@@ -110,7 +110,7 @@ class Snapshot:
         filename: str,
         fileext: str,
         outputs: Dict[str, bool],
-        grid_dl: npt.NDArray[np.single],
+        grid_dl: npt.NDArray[np.float32],
         grid_dt: float,
     ):
         """
@@ -358,7 +358,7 @@ class MPISnapshot(Snapshot):
         filename: str,
         fileext: str,
         outputs: Dict[str, bool],
-        grid_dl: npt.NDArray[np.single],
+        grid_dl: npt.NDArray[np.float32],
         grid_dt: float,
     ):
         super().__init__(

gprMax/vtkhdf_filehandlers/vtk_image_data.py

@@ -0,0 +1,184 @@
+from os import PathLike
+from typing import Literal, Optional, Union
+
+import numpy as np
+import numpy.typing as npt
+from mpi4py import MPI
+
+from gprMax.vtkhdf_filehandlers.vtkhdf import VtkHdfFile
+
+
+class VtkImageData(VtkHdfFile):
+    """File handler for creating a VTKHDF Image Data file.
+
+    File format information is available here:
+    https://docs.vtk.org/en/latest/design_documents/VTKFileFormats.html#image-data
+    """
+
+    DIRECTION_ATTR = "Direction"
+    ORIGIN_ATTR = "Origin"
+    SPACING_ATTR = "Spacing"
+    WHOLE_EXTENT_ATTR = "WholeExtent"
+
+    DIMENSIONS = 3
+
+    @property
+    def TYPE(self) -> Literal["ImageData"]:
+        return "ImageData"
+
+    def __init__(
+        self,
+        filename: Union[str, PathLike],
+        shape: npt.NDArray[np.intc],
+        origin: Optional[npt.NDArray[np.float32]] = None,
+        spacing: Optional[npt.NDArray[np.float32]] = None,
+        direction: Optional[npt.NDArray[np.float32]] = None,
+        comm: Optional[MPI.Comm] = None,
+    ):
+        """Create a new VtkImageData file.
+
+        If the file already exists, it will be overriden. Required
+        attributes (Type and Version) will be written to the file.
+
+        The file will be opened using the 'mpio' h5py driver if an MPI
+        communicator is provided.
+
+        Args:
+            filename: Name of the file (can be a file path). The file
+                extension will be set to '.vtkhdf'.
+            shape: Shape of the image data to be stored in the file.
+                This specifies the number of cells. Image data can be
+                1D, 2D, or 3D.
+            origin (optional): Origin of the image data. Default
+                [0, 0, 0].
+            spacing (optional): Discritisation of the image data.
+                Default [1, 1, 1].
+            direction (optional): Array of direction vectors for each
+                dimension of the image data. Can be a flattened array.
+                I.e. [[1, 0, 0], [0, 1, 0], [0, 0, 1]] and
+                [1, 0, 0, 0, 1, 0, 0, 0, 1] are equivalent. Default
+                [[1, 0, 0], [0, 1, 0], [0, 0, 1]].
+            comm (optional): MPI communicator containing all ranks that
+                want to write to the file.
+        """
+        super().__init__(filename, comm)
+
+        if len(shape) == 0:
+            raise ValueError(f"Shape must not be empty.")
+        if len(shape) > self.DIMENSIONS:
+            raise ValueError(f"Shape must not have more than {self.DIMENSIONS} dimensions.")
+        elif len(shape) < self.DIMENSIONS:
+            shape = np.concatenate((shape, np.ones(self.DIMENSIONS - len(shape), dtype=np.intc)))
+
+        self.shape = shape
+
+        whole_extent = np.zeros(2 * self.DIMENSIONS, dtype=np.intc)
+        whole_extent[1::2] = self.shape
+        self._set_root_attribute(self.WHOLE_EXTENT_ATTR, whole_extent)
+
+        if origin is None:
+            origin = np.zeros(self.DIMENSIONS, dtype=np.float32)
+        self.set_origin(origin)
+
+        if spacing is None:
+            spacing = np.ones(self.DIMENSIONS, dtype=np.float32)
+        self.set_spacing(spacing)
+
+        if direction is None:
+            direction = np.diag(np.ones(self.DIMENSIONS, dtype=np.float32))
+        self.set_direction(direction)
+
+    @property
+    def whole_extent(self) -> npt.NDArray[np.intc]:
+        return self._get_root_attribute(self.WHOLE_EXTENT_ATTR)
+
+    @property
+    def origin(self) -> npt.NDArray[np.float32]:
+        return self._get_root_attribute(self.ORIGIN_ATTR)
+
+    @property
+    def spacing(self) -> npt.NDArray[np.float32]:
+        return self._get_root_attribute(self.SPACING_ATTR)
+
+    @property
+    def direction(self) -> npt.NDArray[np.float32]:
+        return self._get_root_attribute(self.DIRECTION_ATTR)
+
+    def set_origin(self, origin: npt.NDArray[np.float32]):
+        """Set the origin coordinate of the image data.
+
+        Args:
+            origin: x, y, z coordinates to set as the origin.
+        """
+        if len(origin) != self.DIMENSIONS:
+            raise ValueError(f"Origin attribute must have {self.DIMENSIONS} dimensions.")
+        self._set_root_attribute(self.ORIGIN_ATTR, origin)
+
+    def set_spacing(self, spacing: npt.NDArray[np.float32]):
+        """Set the discritisation of the image data.
+
+        Args:
+            spacing: Discritisation of the x, y, and z dimensions.
+        """
+        if len(spacing) != self.DIMENSIONS:
+            raise ValueError(f"Spacing attribute must have {self.DIMENSIONS} dimensions.")
+        self._set_root_attribute(self.SPACING_ATTR, spacing)
+
+    def set_direction(self, direction: npt.NDArray[np.float32]):
+        """Set the coordinate system of the image data.
+
+        Args:
+            direction: Array of direction vectors for each dimension of
+                the image data. Can be a flattened array. I.e.
+                [[1, 0, 0], [0, 1, 0], [0, 0, 1]] and
+                [1, 0, 0, 0, 1, 0, 0, 0, 1] are equivalent.
+        """
+        direction = direction.flatten()
+        if len(direction) != self.DIMENSIONS * self.DIMENSIONS:
+            raise ValueError(
+                f"Direction array must contain {self.DIMENSIONS * self.DIMENSIONS} elements."
+            )
+        self._set_root_attribute(self.DIRECTION_ATTR, direction)
+
+    def add_point_data(
+        self, name: str, data: npt.NDArray, offset: Optional[npt.NDArray[np.intc]] = None
+    ):
+        """Add point data to the VTKHDF file.
+
+        Args:
+            name: Name of the dataset.
+            data: Data to be saved.
+            offset (optional): Offset to store the provided data at. Can
+                be omitted if data provides the full dataset.
+
+        Raises:
+            ValueError: Raised if data has invalid dimensions.
+        """
+        points_shape = self.shape + 1
+        if offset is None and any(data.shape != points_shape):  # type: ignore
+            raise ValueError(
+                "If no offset is specified, data.shape must be one larger in each dimension than"
+                f" this vtkImageData object. {data.shape} != {points_shape}"
+            )
+        return super().add_point_data(name, data, points_shape, offset)
+
+    def add_cell_data(
+        self, name: str, data: npt.NDArray, offset: Optional[npt.NDArray[np.intc]] = None
+    ):
+        """Add cell data to the VTKHDF file.
+
+        Args:
+            name: Name of the dataset.
+            data: Data to be saved.
+            offset (optional): Offset to store the provided data at. Can
+                be omitted if data provides the full dataset.
+
+        Raises:
+            ValueError: Raised if data has invalid dimensions.
+        """
+        if offset is None and any(data.shape != self.shape):  # type: ignore
+            raise ValueError(
+                "If no offset is specified, data.shape must match the dimensions of this"
+                f" VtkImageData object. {data.shape} != {self.shape}"
+            )
+        return super().add_cell_data(name, data, self.shape, offset)

gprMax/vtkhdf_filehandlers/vtk_unstructured_grid.py

@@ -0,0 +1,172 @@
+import logging
+from os import PathLike
+from typing import Literal, Optional, Union
+
+import numpy as np
+import numpy.typing as npt
+from mpi4py import MPI
+
+from gprMax.vtkhdf_filehandlers.vtkhdf import VtkCellType, VtkHdfFile
+
+logger = logging.getLogger(__name__)
+
+
+class VtkUnstructuredGrid(VtkHdfFile):
+    """File handler for creating a VTKHDF Unstructured Grid file.
+
+    File format information is available here:
+    https://docs.vtk.org/en/latest/design_documents/VTKFileFormats.html#unstructured-grid
+    """
+
+    class Dataset(VtkHdfFile.Dataset):
+        CONNECTIVITY = "Connectivity"
+        NUMBER_OF_CELLS = "NumberOfCells"
+        NUMBER_OF_CONNECTIVITY_IDS = "NumberOfConnectivityIds"
+        NUMBER_OF_POINTS = "NumberOfPoints"
+        OFFSETS = "Offsets"
+        POINTS = "Points"
+        TYPES = "Types"
+
+    @property
+    def TYPE(self) -> Literal["UnstructuredGrid"]:
+        return "UnstructuredGrid"
+
+    def __init__(
+        self,
+        filename: Union[str, PathLike],
+        points: npt.NDArray,
+        cell_types: npt.NDArray[VtkCellType],
+        connectivity: npt.NDArray,
+        cell_offsets: npt.NDArray,
+        comm: Optional[MPI.Comm] = None,
+    ) -> None:
+        """Create a new VtkUnstructuredGrid file.
+
+        An unstructured grid has N points and C cells. A cell is defined
+        as a collection of points which is specified by the connectivity
+        and cell_offsets arguments along with the list of cell_types.
+
+        If the file already exists, it will be overriden. Required
+        attributes (Type and Version) will be written to the file.
+
+        The file will be opened using the 'mpio' h5py driver if an MPI
+        communicator is provided.
+
+        Args:
+            filename: Name of the file (can be a file path). The file
+                extension will be set to '.vtkhdf'.
+            points: Array of point coordinates of shape (N, 3).
+            cell_types: Array of VTK cell types of shape (C,).
+            connectivity: Array of point IDs that together with
+                cell_offsets, defines the points that make up each cell.
+                Each point ID has a value between 0 and (N-1) inclusive
+                and corresponds to a point in the points array.
+            cell_offsets: Array listing where each cell starts and ends
+                in the connectivity array. It has shape (C + 1,).
+            comm (optional): MPI communicator containing all ranks that
+                want to write to the file.
+
+        Raises:
+            Value Error: Raised if argument dimensions are invalid.
+        """
+        super().__init__(filename, comm)
+
+        if len(cell_offsets) != len(cell_types) + 1:
+            raise ValueError(
+                "cell_offsets should be one longer than cell_types."
+                " I.e. one longer than the number of cells"
+            )
+
+        is_sorted = lambda a: np.all(a[:-1] <= a[1:])
+        if not is_sorted(cell_offsets):
+            raise ValueError("cell_offsets should be sorted in ascending order")
+
+        if len(connectivity) < cell_offsets[-1]:
+            raise ValueError("Connectivity array is shorter than final cell_offsets value")
+
+        elif len(connectivity) > cell_offsets[-1]:
+            raise logger.warning(
+                "Connectivity array longer than final cell_offsets value."
+                " Some connectivity data will be ignored"
+            )
+
+        self._write_root_dataset(self.Dataset.CONNECTIVITY, connectivity)
+        self._write_root_dataset(self.Dataset.NUMBER_OF_CELLS, len(cell_types))
+        self._write_root_dataset(self.Dataset.NUMBER_OF_CONNECTIVITY_IDS, len(connectivity))
+        self._write_root_dataset(self.Dataset.NUMBER_OF_POINTS, len(points))
+        self._write_root_dataset(self.Dataset.OFFSETS, cell_offsets)
+        self._write_root_dataset(self.Dataset.POINTS, points, xyz_data_ordering=False)
+        self._write_root_dataset(self.Dataset.TYPES, cell_types)
+
+    @property
+    def number_of_cells(self) -> int:
+        number_of_cells = self._get_root_dataset(self.Dataset.NUMBER_OF_CELLS)
+        return np.sum(number_of_cells, dtype=np.intc)
+
+    @property
+    def number_of_connectivity_ids(self) -> int:
+        number_of_connectivity_ids = self._get_root_dataset(self.Dataset.NUMBER_OF_CONNECTIVITY_IDS)
+        return np.sum(number_of_connectivity_ids, dtype=np.intc)
+
+    @property
+    def number_of_points(self) -> int:
+        number_of_points = self._get_root_dataset(self.Dataset.NUMBER_OF_POINTS)
+        return np.sum(number_of_points, dtype=np.intc)
+
+    def add_point_data(
+        self, name: str, data: npt.NDArray, offset: Optional[npt.NDArray[np.intc]] = None
+    ):
+        """Add point data to the VTKHDF file.
+
+        Args:
+            name: Name of the dataset.
+            data: Data to be saved.
+            offset (optional): Offset to store the provided data at. Can
+                be omitted if data provides the full dataset.
+
+        Raises:
+            ValueError: Raised if data has invalid dimensions.
+        """
+        shape = np.array(data.shape)
+        number_of_dimensions = len(shape)
+
+        if number_of_dimensions < 1 or number_of_dimensions > 2:
+            raise ValueError(f"Data must have 1 or 2 dimensions, not {number_of_dimensions}")
+        elif len(data) != self.number_of_points:
+            raise ValueError(
+                "Length of data must match the number of points in the vtkUnstructuredGrid."
+                f" {len(data)} != {self.number_of_points}"
+            )
+        elif number_of_dimensions == 2 and shape[1] != 1 and shape[1] != 3:
+            raise ValueError(f"The second dimension should have shape 1 or 3, not {shape[1]}")
+
+        return super().add_point_data(name, data, shape, offset)
+
+    def add_cell_data(
+        self, name: str, data: npt.NDArray, offset: Optional[npt.NDArray[np.intc]] = None
+    ):
+        """Add cell data to the VTKHDF file.
+
+        Args:
+            name: Name of the dataset.
+            data: Data to be saved.
+            offset (optional): Offset to store the provided data at. Can
+                be omitted if data provides the full dataset.
+
+        Raises:
+            ValueError: Raised if data has invalid dimensions.
+        """
+        shape = np.array(data.shape)
+        number_of_dimensions = len(shape)
+
+        if number_of_dimensions < 1 or number_of_dimensions > 2:
+            raise ValueError(f"Data must have 1 or 2 dimensions, not {number_of_dimensions}.")
+        elif len(data) != self.number_of_cells:
+            raise ValueError(
+                "Length of data must match the number of cells in the vtkUnstructuredGrid."
+                f" {len(data)} != {self.number_of_cells}"
+            )
+        elif number_of_dimensions == 2 and shape[1] != 1 and shape[1] != 3:
+            raise ValueError(f"The second dimension should have shape 1 or 3, not {shape[1]}")
+
+        return super().add_cell_data(name, data, shape, offset)

gprMax/vtkhdf_filehandlers/vtkhdf.py

@@ -0,0 +1,386 @@
+import logging
+from abc import abstractmethod
+from contextlib import AbstractContextManager
+from enum import Enum
+from os import PathLike
+from pathlib import Path
+from types import TracebackType
+from typing import Optional, Union
+
+import h5py
+import numpy as np
+import numpy.typing as npt
+from mpi4py import MPI
+
+logger = logging.getLogger(__name__)
+
+
+class VtkHdfFile(AbstractContextManager):
+    VERSION = [2, 2]
+    FILE_EXTENSION = ".vtkhdf"
+    ROOT_GROUP = "VTKHDF"
+
+    # TODO: Can this be moved to using an Enum like root datasets?
+    # Main barrier: Can't subclass an enum with members and any base
+    # Enum class would need VERSION and TYPE as members.
+    VERSION_ATTR = "Version"
+    TYPE_ATTR = "Type"
+
+    class Dataset(str, Enum):
+        pass
+
+    @property
+    @abstractmethod
+    def TYPE(self) -> str:
+        pass
+
+    def __enter__(self):
+        return self
+
+    def __init__(self, filename: Union[str, PathLike], comm: Optional[MPI.Comm] = None) -> None:
+        """Create a new VtkHdfFile.
+
+        If the file already exists, it will be overriden. Required
+        attributes (Type and Version) will be written to the file.
+
+        The file will be opened using the 'mpio' h5py driver if an MPI
+        communicator is provided.
+
+        Args:
+            filename: Name of the file (can be a file path). The file
+                extension will be set to '.vtkhdf'.
+            comm (optional): MPI communicator containing all ranks that
+                want to write to the file.
+
+        """
+        # Ensure the filename uses the correct extension
+        self.filename = Path(filename)
+        if self.filename.suffix != "" and self.filename.suffix != self.FILE_EXTENSION:
+            logger.warning(
+                f"Invalid file extension '{self.filename.suffix}' for VTKHDF file. Changing to '{self.FILE_EXTENSION}'."
+            )
+
+        self.filename = self.filename.with_suffix(self.FILE_EXTENSION)
+
+        self.comm = comm
+
+        # Check if the filehandler should use an MPI driver
+        if self.comm is None:
+            self.file_handler = h5py.File(self.filename, "w")
+        else:
+            self.file_handler = h5py.File(self.filename, "w", driver="mpio", comm=self.comm)
+
+        self.root_group = self.file_handler.create_group(self.ROOT_GROUP)
+
+        # Set required Version and Type root attributes
+        self._set_root_attribute(self.VERSION_ATTR, self.VERSION)
+
+        type_as_ascii = self.TYPE.encode("ascii")
+        self._set_root_attribute(
+            self.TYPE_ATTR, type_as_ascii, h5py.string_dtype("ascii", len(type_as_ascii))
+        )
+
+    def __exit__(
+        self,
+        exc_type: Optional[type[BaseException]],
+        exc_value: Optional[BaseException],
+        traceback: Optional[TracebackType],
+    ) -> Optional[bool]:
+        """Close the file when the context is exited.
+
+        The parameters describe the exception that caused the context to
+        be exited. If the context was exited without an exception, all
+        three arguments will be None. Any exception will be
+        processed normally upon exit from this method.
+
+        Returns:
+            suppress_exception (optional): Returns True if the exception
+                should be suppressed (i.e. not propagated). Otherwise,
+                the exception will be processed normally upon exit from
+                this method.
+        """
+        self.close()
+
+    def close(self) -> None:
+        """Close the file handler"""
+        self.file_handler.close()
+
+    def _get_root_attribute(self, attribute: str) -> npt.NDArray:
+        """Get attribute from the root VTKHDF group if it exists.
+
+        Args:
+            attribute: Name of the attribute.
+
+        Returns:
+            value: Current value of the attribute if it exists.
+
+        Raises:
+            KeyError: Raised if the attribute is not present as a key.
+        """
+        value = self.root_group.attrs[attribute]
+        if isinstance(value, h5py.Empty):
+            raise KeyError(f"Attribute '{attribute}' not present in /{self.ROOT_GROUP} group")
+        return value
+
+    def _set_root_attribute(
+        self, attribute: str, value: npt.ArrayLike, dtype: npt.DTypeLike = None
+    ):
+        """Set attribute in the root VTKHDF group.
+
+        Args:
+            attribute: Name of the new attribute.
+            value: An array to initialize the attribute.
+            dtype (optional): Data type of the attribute. Overrides
+                value.dtype if both are given.
+        """
+        self.root_group.attrs.create(attribute, value, dtype=dtype)
+
+    def _build_dataset_path(self, *path: str) -> str:
+        """Build an HDF5 dataset path attached to the root VTKHDF group.
+
+        Args:
+            *path: Components of the required path.
+
+        Returns:
+            path: Path to the dataset.
+        """
+        return "/".join([self.ROOT_GROUP, *path])
+
+    def _get_root_dataset(self, name: "VtkHdfFile.Dataset") -> h5py.Dataset:
+        """Get specified dataset from the root group of the VTKHDF file.
+
+        Args:
+            path: Name of the dataset.
+
+        Returns:
+            dataset: Returns specified h5py dataset.
+        """
+        path = self._build_dataset_path(name)
+        return self._get_dataset(path)
+
+    def _get_dataset(self, path: str) -> h5py.Dataset:
+        """Get specified dataset.
+
+        Args:
+            path: Absolute path to the dataset.
+
+        Returns:
+            dataset: Returns specified h5py dataset.
+
+        Raises:
+            KeyError: Raised if the dataset does not exist, or the path
+                points to some other object, e.g. a Group not a Dataset.
+        """
+        cls = self.file_handler.get(path, getclass=True)
+        if cls == "default":
+            raise KeyError("Path does not exist")
+        elif cls != h5py.Dataset:
+            raise KeyError(f"Dataset not found. Found '{cls}' instead")
+
+        dataset = self.file_handler.get(path)
+        assert isinstance(dataset, h5py.Dataset)
+        return dataset
+
+    def _write_root_dataset(
+        self,
+        name: "VtkHdfFile.Dataset",
+        data: npt.ArrayLike,
+        shape: Optional[npt.NDArray[np.intc]] = None,
+        offset: Optional[npt.NDArray[np.intc]] = None,
+        xyz_data_ordering=True,
+    ):
+        """Write specified dataset to the root group of the VTKHDF file.
+
+        Args:
+            name: Name of the dataset.
+            data: Data to initialize the dataset.
+            shape (optional): Size of the full dataset being created.
+                Can be omitted if data provides the full dataset.
+            offset (optional): Offset to store the provided data at. Can
+                be omitted if data provides the full dataset.
+            xyz_data_ordering (optional): If True, the data will be
+                transposed as VTKHDF stores datasets using ZYX ordering.
+                Default True.
+        """
+        path = self._build_dataset_path(name)
+        self._write_dataset(
+            path, data, shape=shape, offset=offset, xyz_data_ordering=xyz_data_ordering
+        )
+
+    def _write_dataset(
+        self,
+        path: str,
+        data: npt.ArrayLike,
+        shape: Optional[npt.NDArray[np.intc]] = None,
+        offset: Optional[npt.NDArray[np.intc]] = None,
+        dtype: Optional[npt.DTypeLike] = None,
+        xyz_data_ordering=True,
+    ):
+        """Write specified dataset to the VTKHDF file.
+
+        If data has shape (d1, d2, ..., dn), i.e. n dimensions, then, if
+        specified, shape and offset must be of length n.
+
+        Args:
+            path: Absolute path to the dataset.
+            data: Data to initialize the dataset.
+            shape (optional): Size of the full dataset being created.
+                Can be omitted if data provides the full dataset.
+            offset (optional): Offset to store the provided data at. Can
+                be omitted if data provides the full dataset.
+            xyz_data_ordering (optional): If True, the data will be
+                transposed as VTKHDF stores datasets using ZYX ordering.
+                Default True.
+
+        Raises:
+            ValueError: Raised if the combination of data.shape, shape,
+                and offset are invalid.
+        """
+
+        # If dtype is a string, ensure it is ascii encoded and use
+        # variable length strings
+        if dtype is not None and h5py.check_string_dtype(dtype) is not None:
+            dtype = h5py.string_dtype(encoding="ascii", length=None)
+
+        if not isinstance(data, np.ndarray):
+            data = np.array(data, dtype=dtype)
+            if data.ndim < 1:
+                data = np.expand_dims(data, axis=-1)
+
+        if dtype is None:
+            dtype = data.dtype
+
+        # VTKHDF stores datasets using ZYX ordering rather than XYZ
+        if xyz_data_ordering:
+            data = data.transpose()
+
+        if shape is not None:
+            shape = np.flip(shape)
+
+        if offset is not None:
+            offset = np.flip(offset)
+
+        if shape is None or all(shape == data.shape):
+            self.file_handler.create_dataset(path, data=data, dtype=dtype)
+        elif offset is None:
+            raise ValueError(
+                "Offset must not be None as the full dataset has not been provided."
+                " I.e. data.shape != shape"
+            )
+        else:
+            dimensions = len(data.shape)
+
+            if dimensions != len(shape):
+                raise ValueError(
+                    "The data and specified shape must have the same number of dimensions."
+                    f" {dimensions} != {len(shape)}"
+                )
+
+            if dimensions != len(offset):
+                raise ValueError(
+                    "The data and specified offset must have the same number of dimensions."
+                    f" {dimensions} != {len(offset)}"
+                )
+
+            if any(offset + data.shape > shape):
+                raise ValueError(
+                    "The provided offset and data does not fit within the bounds of the dataset."
+                    f" {offset} + {data.shape} = {offset + data.shape} > {shape}"
+                )
+
+            dataset = self.file_handler.create_dataset(path, shape=shape, dtype=dtype)
+
+            start = offset
+            stop = offset + data.shape
+
+            dataset_slice = (slice(start[i], stop[i]) for i in range(dimensions))
+
+            dataset[dataset_slice] = data
+
+    def add_point_data(
+        self,
+        name: str,
+        data: npt.NDArray,
+        shape: Optional[npt.NDArray[np.intc]] = None,
+        offset: Optional[npt.NDArray[np.intc]] = None,
+    ):
+        """Add point data to the VTKHDF file.
+
+        Args:
+            name: Name of the dataset.
+            data: Data to be saved.
+            shape (optional): Size of the full dataset being created.
+                Can be omitted if data provides the full dataset.
+            offset (optional): Offset to store the provided data at. Can
+                be omitted if data provides the full dataset.
+        """
+        dataset_path = self._build_dataset_path("PointData", name)
+        self._write_dataset(dataset_path, data, shape=shape, offset=offset)
+
+    def add_cell_data(
+        self,
+        name: str,
+        data: npt.NDArray,
+        shape: Optional[npt.NDArray[np.intc]] = None,
+        offset: Optional[npt.NDArray[np.intc]] = None,
+    ):
+        """Add cell data to the VTKHDF file.
+
+        Args:
+            name: Name of the dataset.
+            data: Data to be saved.
+            shape (optional): Size of the full dataset being created.
+                Can be omitted if data provides the full dataset.
+            offset (optional): Offset to store the provided data at. Can
+                be omitted if data provides the full dataset.
+        """
+        dataset_path = self._build_dataset_path("CellData", name)
+        self._write_dataset(dataset_path, data, shape=shape, offset=offset)
+
+    def add_field_data(
+        self,
+        name: str,
+        data: npt.ArrayLike,
+        shape: Optional[npt.NDArray[np.intc]] = None,
+        offset: Optional[npt.NDArray[np.intc]] = None,
+        dtype: Optional[npt.DTypeLike] = None,
+    ):
+        """Add field data to the VTKHDF file.
+
+        Args:
+            name: Name of the dataset.
+            data: Data to be saved.
+            shape (optional): Size of the full dataset being created.
+                Can be omitted if data provides the full dataset.
+            offset (optional): Offset to store the provided data at. Can
+                be omitted if data provides the full dataset.
+        """
+        dataset_path = self._build_dataset_path("FieldData", name)
+        self._write_dataset(
+            dataset_path, data, shape=shape, offset=offset, dtype=dtype, xyz_data_ordering=False
+        )
+
+
+class VtkCellType(np.uint8, Enum):
+    """VTK cell types as defined here:
+    https://vtk.org/doc/nightly/html/vtkCellType_8h_source.html#l00019
+    """
+
+    # Linear cells
+    EMPTY_CELL = 0
+    VERTEX = 1
+    POLY_VERTEX = 2
+    LINE = 3
+    POLY_LINE = 4
+    TRIANGLE = 5
+    TRIANGLE_STRIP = 6
+    POLYGON = 7
+    PIXEL = 8
+    QUAD = 9
+    TETRA = 10
+    VOXEL = 11
+    HEXAHEDRON = 12
+    WEDGE = 13
+    PYRAMID = 14
+    PENTAGONAL_PRISM = 15
+    HEXAGONAL_PRISM = 16

reframe_tests/regression_checks/TestGeometryView_5176823e/full_volume.vtkhdf

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:4a8134fca3e6228211e4a4bc3e504e64f888c55f22e025b482ec501e0051d253
+size 75740296

reframe_tests/regression_checks/TestGeometryView_5176823e/partial_volume.vtkhdf

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:2ccd95ff4ef73c224c99a8c321ad6f8014c673a1b33bbb741bff415dfbffd0aa
+size 4931176

reframe_tests/regression_checks/TestGeometryView_77980202/full_volume.vtkhdf

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:82b8ac914a9fe20b49f2512215782f01305a2e3211aaac51913f88296a0e3ac5
+size 4012444

reframe_tests/tests/base_tests.py

@@ -182,7 +182,7 @@ class GprMaxBaseTest(RunOnlyRegressionTest):
         else:
             return self.getdep(variant)
 
-    def build_reference_filepath(self, name: Union[str, os.PathLike]) -> Path:
+    def build_reference_filepath(self, name: Union[str, os.PathLike], suffix: str = ".h5") -> Path:
         """Build path to the specified reference file.
 
         Reference files are saved in directories per test case. If this
@@ -192,6 +192,7 @@ class GprMaxBaseTest(RunOnlyRegressionTest):
 
         Args:
             name: Name of the file.
+            suffix: File extension. Default ".h5".
 
         Returns:
             filepath: Absolute path to the reference file.
@@ -202,7 +203,7 @@ class GprMaxBaseTest(RunOnlyRegressionTest):
         else:
             reference_dir = target.short_name
 
-        reference_file = Path("regression_checks", reference_dir, name).with_suffix(".h5")
+        reference_file = Path("regression_checks", reference_dir, name).with_suffix(suffix)
         return reference_file.absolute()
 
     # TODO: Change CreatePyenvTest to a fixture instead of a test dependency

reframe_tests/tests/mixins.py

@@ -9,6 +9,7 @@ from typing_extensions import TYPE_CHECKING
 
 from reframe_tests.tests.base_tests import GprMaxBaseTest
 from reframe_tests.tests.regression_checks import (
+    GeometryViewRegressionCheck,
     ReceiverRegressionCheck,
     RegressionCheck,
     SnapshotRegressionCheck,
@@ -77,6 +78,50 @@ class SnapshotMixin(GprMaxMixin):
             self.regression_checks.append(regression_check)
 
 
+class GeometryOnlyMixin(GprMaxMixin):
+    """Run test with geometry only flag"""
+
+    @run_after("setup")
+    def add_geometry_only_flag(self):
+        self.executable_opts += ["--geometry-only"]
+
+
+class GeometryViewMixin(GprMaxMixin):
+    """Add regression tests for geometry views.
+
+    Attributes:
+        geometry_views (list[str]): List of geometry views to run
+            regression checks on.
+    """
+
+    geometry_views = variable(typ.List[str], value=[])
+
+    def build_geometry_view_filepath(self, geometry_view: str) -> Path:
+        """Build filepath to the specified geometry view.
+
+        Args:
+            geometry_view: Name of the geometry view.
+        """
+        return Path(geometry_view).with_suffix(".vtkhdf")
+
+    @run_after("setup")
+    def add_geometry_view_regression_checks(self):
+        """Add a regression check for each geometry view.
+
+        The test will be skipped if no geometry views have been specified.
+        """
+        self.skip_if(
+            len(self.geometry_views) < 0,
+            f"Must provide a list of geometry views.",
+        )
+
+        for geometry_view in self.geometry_views:
+            geometry_view_file = self.build_geometry_view_filepath(geometry_view)
+            reference_file = self.build_reference_filepath(geometry_view, ".vtkhdf")
+            regression_check = GeometryViewRegressionCheck(geometry_view_file, reference_file)
+            self.regression_checks.append(regression_check)
+
+
 class PythonApiMixin(GprMaxMixin):
     """Use the GprMax Python API rather than a standard input file."""
 

reframe_tests/tests/regression_checks.py

@@ -74,7 +74,12 @@ class RegressionCheck:
             h5diff = "h5diff"
 
         h5diff_output = osext.run_command(
-            [h5diff, *self.h5diff_options, str(self.output_file), str(self.reference_file)]
+            [
+                h5diff,
+                *self.h5diff_options,
+                str(self.output_file.absolute()),
+                str(self.reference_file),
+            ]
         )
 
         return sn.assert_true(
@@ -135,3 +140,11 @@ class SnapshotRegressionCheck(RegressionCheck):
     @property
     def error_msg(self) -> str:
         return f"Snapshot '{self.output_file.name}' failed regression check "
+
+
+class GeometryViewRegressionCheck(RegressionCheck):
+    """Run regression check on a GprMax GeometryView."""
+
+    @property
+    def error_msg(self) -> str:
+        return f"GeometryView '{self.output_file.name}' failed regression check "

reframe_tests/tests/src/geometry_view_tests/geometry_view_fine.in

@@ -0,0 +1,17 @@
+#title: Hertzian dipole in free-space
+#domain: 0.100 0.100 0.100
+#dx_dy_dz: 0.001 0.001 0.001
+#time_window: 3e-9
+
+#waveform: gaussiandot 1 1e9 myWave
+#hertzian_dipole: z 0.050 0.050 0.050 myWave
+
+#material: 4.9 0 1 0 myWater
+#material: 2 0 1.4 0 unusedMaterial
+#material: 3 0 2 0 boxMaterial
+
+#sphere: 0.05 0.05 0.05 0.03 myWater y
+#box: 0.01 0.01 0.01 0.09 0.025 0.025 boxMaterial y
+
+#geometry_view: 0.02 0.02 0.02 0.06 0.06 0.06 0.001 0.001 0.001 partial_volume f
+#geometry_view: 0 0 0 0.1 0.1 0.1 0.001 0.001 0.001 full_volume f

reframe_tests/tests/src/geometry_view_tests/geometry_view_voxel.in

@@ -0,0 +1,17 @@
+#title: Hertzian dipole in free-space
+#domain: 0.100 0.100 0.100
+#dx_dy_dz: 0.001 0.001 0.001
+#time_window: 3e-9
+
+#waveform: gaussiandot 1 1e9 myWave
+#hertzian_dipole: z 0.050 0.050 0.050 myWave
+
+#material: 4.9 0 1 0 myWater
+#material: 2 0 1.4 0 unusedMaterial
+#material: 3 0 2 0 boxMaterial
+
+#sphere: 0.05 0.05 0.05 0.03 myWater y
+#box: 0.01 0.01 0.01 0.09 0.025 0.025 boxMaterial y
+
+#geometry_view: 0.02 0.02 0.02 0.06 0.06 0.06 0.001 0.001 0.001 partial_volume n
+#geometry_view: 0 0 0 0.1 0.1 0.1 0.001 0.001 0.001 full_volume n

reframe_tests/tests/standard_tests.py

@@ -1,5 +1,10 @@
 from reframe_tests.tests.base_tests import GprMaxBaseTest
-from reframe_tests.tests.mixins import ReceiverMixin, SnapshotMixin
+from reframe_tests.tests.mixins import (
+    GeometryOnlyMixin,
+    GeometryViewMixin,
+    ReceiverMixin,
+    SnapshotMixin,
+)
 
 
 class GprMaxRegressionTest(ReceiverMixin, GprMaxBaseTest):
@@ -8,3 +13,7 @@ class GprMaxRegressionTest(ReceiverMixin, GprMaxBaseTest):
 
 class GprMaxSnapshotTest(SnapshotMixin, GprMaxBaseTest):
     pass
+
+
+class GprMaxGeometryViewTest(GeometryViewMixin, GeometryOnlyMixin, GprMaxBaseTest):
+    pass

reframe_tests/tests/test_geometry_views.py

@@ -0,0 +1,20 @@
+import reframe as rfm
+from reframe.core.builtins import parameter
+
+from reframe_tests.tests.mixins import MpiMixin
+from reframe_tests.tests.standard_tests import GprMaxGeometryViewTest
+
+
+@rfm.simple_test
+class TestGeometryView(GprMaxGeometryViewTest):
+    tags = {"test", "serial", "geometry only", "geometry view"}
+    sourcesdir = "src/geometry_view_tests"
+    model = parameter(["geometry_view_voxel", "geometry_view_fine"])
+    geometry_views = ["partial_volume", "full_volume"]
+
+
+@rfm.simple_test
+class TestGeometryViewMPI(MpiMixin, TestGeometryView):
+    tags = {"test", "mpi", "geometry only", "geometry view"}
+    mpi_layout = parameter([[2, 2, 2], [4, 4, 1]])
+    test_dependency = TestGeometryView

toolboxes/Utilities/Paraview/gprMax.py

@@ -16,69 +16,103 @@
 # You should have received a copy of the GNU General Public License
 # along with gprMax.  If not, see <http://www.gnu.org/licenses/>.
 
-import json
-import os
-
+from paraview.servermanager import Proxy, SourceProxy
 from paraview.simple import (
     AppendDatasets,
     Box,
+    ColorBy,
+    FetchData,
     GetActiveSource,
     GetActiveView,
+    GetDisplayProperties,
     GetParaViewVersion,
     Hide,
-    OpenDataFile,
     RenameSource,
     RenderAllViews,
     SetActiveSource,
     Show,
     Threshold,
 )
+from paraview.vtk.numpy_interface import dataset_adapter as dsa
+from vtkmodules.vtkCommonCore import vtkStringArray
+
+COLOUR_SCALARS = ("CELLS", "Material")
 
 
-def threshold_filt(input, lt, ut, scalars):
+def threshold_materials(source: SourceProxy, view: Proxy, material_ids: vtkStringArray):
     """Create threshold filter according to Paraview version.
 
     Args:
-        input (array): input data to threshold filter
-        lt, ut (int): lower and upper bounds of thresholding operation
-        scalars (list/str): name of scalar array to perform thresholding
-
-    Returns:
-        threshold (object): threshold filter
+        source: Input to the threshold filter.
+        view: The view proxy to show the threshold in.
+        material_ids: Array of material ids. A new threshold filter will
+            be created for each material.
     """
 
     # Read Paraview version number to set threshold filter method
     pvv = GetParaViewVersion()
 
-    threshold = Threshold(Input=input)
-    threshold.Scalars = scalars
+    for index in range(material_ids.GetNumberOfValues()):
+        threshold = Threshold(Input=source, Scalars=COLOUR_SCALARS)
 
         if pvv.major == 5 and pvv.minor < 10:
-        threshold.ThresholdRange = [lt, ut]
+            threshold.ThresholdRange = [index, index]
         else:
-        threshold.LowerThreshold = lt
-        threshold.UpperThreshold = ut
+            threshold.LowerThreshold = index
+            threshold.UpperThreshold = index
 
-    return threshold
+        RenameSource(material_ids.GetValue(index), threshold)
+
+        # Show data in view, except for free_space
+        if index != 1:
+            Show(threshold, view)
+
+        threshold.UpdatePipeline()
 
 
-def display_pmls(pmlthick, dx_dy_dz, nx_ny_nz):
-    """Display PMLs as box sources using PML thickness values.
-        Only suitable for gprMax >= v4
+def create_box_sources(names: vtkStringArray, positions: dsa.VTKArray, dl: dsa.VTKArray):
+    """Create new single cell box sources.
 
     Args:
-        pmlthick (tuple): PML thickness values for each slab (cells)
-        dx_dy_dz (tuple): Spatial resolution (m)
-        nx_ny_dz (tuple): Domain size (cells)
+        names: Array of N names for the new sources.
+        positions: x, y, z coordinates of the new sources. This should
+            have shape (N, 3).
+        dl: x, y, z spatial resolution.
+    """
+    for index in range(names.GetNumberOfValues()):
+        name = names.GetValue(index)
+        pos = positions[index]
+        src = Box(
+            Center=pos + dl / 2,
+            XLength=dl[0],
+            YLength=dl[1],
+            ZLength=dl[2],
+        )
+        RenameSource(name, src)
+        Show(src)
+
+
+def display_pmls(pmlthick: dsa.VTKArray, dx_dy_dz: dsa.VTKArray, nx_ny_nz: dsa.VTKArray):
+    """Display PMLs as box sources using PML thickness values.
+
+    Only suitable for gprMax >= v4.
+
+    Args:
+        pmlthick: PML thickness values for each slab (cells).
+        dx_dy_dz: Spatial resolution (m).
+        nx_ny_dz: Domain size (cells).
     """
 
     pml_names = ["x0", "y0", "z0", "xmax", "ymax", "zmax"]
     pmls = dict.fromkeys(pml_names, None)
-    SetActiveSource(pv_data)
 
     if pmlthick[0] != 0:
         x0 = Box(
-            Center=[pmlthick[0] * dx_dy_dz[0] / 2, nx_ny_nz[1] * dx_dy_dz[1] / 2, nx_ny_nz[2] * dx_dy_dz[2] / 2],
+            Center=[
+                pmlthick[0] * dx_dy_dz[0] / 2,
+                nx_ny_nz[1] * dx_dy_dz[1] / 2,
+                nx_ny_nz[2] * dx_dy_dz[2] / 2,
+            ],
             XLength=pmlthick[0] * dx_dy_dz[0],
             YLength=nx_ny_nz[1] * dx_dy_dz[1],
             ZLength=nx_ny_nz[2] * dx_dy_dz[2],
@@ -100,7 +134,11 @@ def display_pmls(pmlthick, dx_dy_dz, nx_ny_nz):
 
     if pmlthick[1] != 0:
         y0 = Box(
-            Center=[nx_ny_nz[0] * dx_dy_dz[0] / 2, pmlthick[1] * dx_dy_dz[1] / 2, nx_ny_nz[2] * dx_dy_dz[2] / 2],
+            Center=[
+                nx_ny_nz[0] * dx_dy_dz[0] / 2,
+                pmlthick[1] * dx_dy_dz[1] / 2,
+                nx_ny_nz[2] * dx_dy_dz[2] / 2,
+            ],
             XLength=nx_ny_nz[0] * dx_dy_dz[0],
             YLength=pmlthick[1] * dx_dy_dz[1],
             ZLength=nx_ny_nz[2] * dx_dy_dz[2],
@@ -122,7 +160,11 @@ def display_pmls(pmlthick, dx_dy_dz, nx_ny_nz):
 
     if pmlthick[2] != 0:
         z0 = Box(
-            Center=[nx_ny_nz[0] * dx_dy_dz[0] / 2, nx_ny_nz[1] * dx_dy_dz[1] / 2, pmlthick[2] * dx_dy_dz[2] / 2],
+            Center=[
+                nx_ny_nz[0] * dx_dy_dz[0] / 2,
+                nx_ny_nz[1] * dx_dy_dz[1] / 2,
+                pmlthick[2] * dx_dy_dz[2] / 2,
+            ],
             XLength=nx_ny_nz[0] * dx_dy_dz[0],
             YLength=nx_ny_nz[1] * dx_dy_dz[1],
             ZLength=pmlthick[2] * dx_dy_dz[2],
@@ -158,96 +200,122 @@ def display_pmls(pmlthick, dx_dy_dz, nx_ny_nz):
         pml_view.Opacity = 0.5
 
 
-# Get whatever source is loaded - should be loaded file (.vt*) or files (.pvd)
-pv_data = GetActiveSource()
+def is_valid_key(key: str, dictionary: dict) -> bool:
+    """Check key exists and is not an empty array (i.e. VTKNoneArray).
 
-# Hide display of root data
-Hide(pv_data)
+    Args:
+        key: Name of key to check.
+        dictionary: Dictionary like object that should contain the key.
 
-# Single .vti or .vtu file
-file = pv_data.FileName[0]
+    Returns:
+        is_valid_key: True if the key is in the dictionary and is not
+            of type VTKNoneArray. False otherwise.
+    """
+    return key in dictionary.keys() and not isinstance(dictionary[key], dsa.VTKNoneArray)
 
-# Read and display data from file, i.e. materials, sources,  receivers, and PMLs
-with open(file, "rb") as f:
-    # Comments () embedded in line 3 of file
-    f.readline()
-    f.readline()
-    c = f.readline().decode()
-    # Strip comment tags
-    c = c[5:-5]
-    # Model information
-    c = json.loads(c)
-    print("\ngprMax version: " + c["gprMax_version"])
-    print(file)
+
+class HaltException(Exception):
+    pass
+
+
+try:
+    print("=============== Running gprMax macro ===============", end="\n\n")
+
+    # Get active source - should be loaded file (.vtkhdf)
+    pv_source = GetActiveSource()
+
+    if pv_source is None:
+        raise HaltException("ERROR: No active source.")
+
+    pv_source.UpdatePipeline()
+
+    raw_data = FetchData(pv_source)[0]
+    data = dsa.WrapDataObject(raw_data)
+
+    # Check the necessary metadata is attached to the file
+    metadata_keys = data.FieldData.keys()
+    compulsory_keys = ["gprMax_version", "nx_ny_nz", "dx_dy_dz", "material_ids"]
+    missing_keys = []
+    for key in compulsory_keys:
+        if key not in metadata_keys:
+            missing_keys.append(key)
+
+    if len(missing_keys) > 0:
+        keys = "\n- ".join(missing_keys)
+        print(f"Missing metadata fields: \n- {keys}\n")
+        if len(metadata_keys) > 0:
+            keys = "\n- ".join(metadata_keys)
+            print(f"Found:  \n- {keys}\n")
+        raise HaltException(
+            "ERROR: Missing gprMax metadata information. Do you have the correct source selected?"
+        )
+
+    # gprMax version
+    version = data.FieldData["gprMax_version"].GetValue(0)
+    # Number of voxels
+    nl = data.FieldData["nx_ny_nz"]
+    # Discretisation
+    dl = data.FieldData["dx_dy_dz"]
+
+    print("gprMax version:", data.FieldData["gprMax_version"].GetValue(0))
+    print("nx_ny_nz:", nl)
+    print("dx_dy_dz:", dl, end="\n\n")
 
     ################
     # Display data #
     ################
+
+    # Get active view
     pv_view = GetActiveView()
     pv_view.AxesGrid.Visibility = 1  # Show Data Axes Grid
-pv_disp = Show(pv_data, pv_view)
-pv_disp.ColorArrayName = ["CELLS", "Material"]
 
-# Discretisation
-dl = c["dx_dy_dz"]
-# Number of voxels
-nl = c["nx_ny_nz"]
+    # Get display properties
+    pv_disp = GetDisplayProperties(pv_source, view=pv_view)
+
+    # Set scalar colouring
+    ColorBy(pv_disp, COLOUR_SCALARS)
 
     # Materials
-try:
-    for i, mat in enumerate(c["Materials"]):
-        threshold = threshold_filt(pv_data, i, i, ["CELLS", "Material"])
-        RenameSource(mat, threshold)
-
-        # Show data in view, except for free_space
-        if i != 1:
-            thresholddisplay = Show(threshold, pv_view)
-            thresholddisplay.ColorArrayName = ["CELLS", "Material"]
-        threshold.UpdatePipeline()
-except KeyError:
-    print("No materials to load")
+    print("Loading materials... ", end="\t")
+    if is_valid_key("material_ids", data.FieldData):
+        threshold_materials(pv_source, pv_view, data.FieldData["material_ids"])
+        print("Done.")
+    else:
+        print("No materials to load.")
 
     # Display any sources
-try:
-    for item in c["Sources"]:
-        pos = item["position"]
-        name = item["name"]
-        src = Box(
-            Center=[pos[0] + dl[0] / 2, pos[1] + dl[1] / 2, pos[2] + dl[2] / 2],
-            XLength=dl[0],
-            YLength=dl[1],
-            ZLength=dl[2],
-        )
-        RenameSource(name, src)
-        Show(src)
-except KeyError:
-    print("No sources to load")
+    print("Loading sources... ", end="\t\t")
+    if is_valid_key("source_ids", data.FieldData) and is_valid_key("sources", data.FieldData):
+        create_box_sources(data.FieldData["source_ids"], data.FieldData["sources"], dl)
+        print("Done.")
+    else:
+        print("No sources to load.")
 
     # Display any receivers
-try:
-    for item in c["Receivers"]:
-        pos = item["position"]
-        name = item["name"]
-        rx = Box(
-            Center=[pos[0] + dl[0] / 2, pos[1] + dl[1] / 2, pos[2] + dl[2] / 2],
-            XLength=dl[0],
-            YLength=dl[1],
-            ZLength=dl[2],
-        )
-        RenameSource(name, rx)
-        Show(rx)
-except KeyError:
-    print("No receivers to load")
+    print("Loading receivers... ", end="\t")
+    if is_valid_key("receiver_ids", data.FieldData) and is_valid_key("receivers", data.FieldData):
+        create_box_sources(data.FieldData["receiver_ids"], data.FieldData["receivers"], dl)
+        print("Done.")
+    else:
+        print("No receivers to load.")
 
     # Display any PMLs
-try:
-    pt = c["PMLthickness"]
-    display_pmls(pt, dl, nl)
-except KeyError:
-    print("No PMLs to load")
-
+    print("Loading PMLs... ", end="\t\t")
+    if is_valid_key("pml_thickness", data.FieldData):
+        display_pmls(data.FieldData["pml_thickness"], dl, nl)
+        print("Done.")
+    else:
+        print("No PMLs to load.")
 
     RenderAllViews()
 
+    SetActiveSource(pv_source)
+    Hide(pv_source)
+
     # Reset view to fit data
     pv_view.ResetCamera()
+
+except HaltException as e:
+    print(e)
+
+print()