Fix bug when objects start in a positive halo

Objects with a thickness (triangles and circular sectors) can no longer
extend beyond the grid in the dimension they are aligned to.

Building these objects where the lower extent is aligned with a positive
halo, no longer corrupts memory due to out of bounds memory access

gprMax/user_inputs.py

@@ -140,6 +140,9 @@ class UserInput(Generic[GridType]):
         """
         return self.discretise_point(point) * self.grid.dl
 
+    def discrete_to_continuous(self, point: npt.NDArray[np.int32]) -> npt.NDArray[np.float64]:
+        return point * self.grid.dl
+
 
 class MainGridUserInput(UserInput[GridType]):
     """Handles (x, y, z) points supplied by the user in the main grid."""
@@ -199,30 +202,29 @@ class MainGridUserInput(UserInput[GridType]):
         p2: Tuple[float, float, float],
         p3: Tuple[float, float, float],
         cmd_str: str,
-    ) -> Tuple[bool, npt.NDArray[np.int32], npt.NDArray[np.int32], npt.NDArray[np.int32]]:
-        p1_within_grid, p1_checked = self.check_point(p1, cmd_str, name="vertex_1")
-        p2_within_grid, p2_checked = self.check_point(p2, cmd_str, name="vertex_2")
-        p3_within_grid, p3_checked = self.check_point(p3, cmd_str, name="vertex_3")
+    ) -> Tuple[npt.NDArray[np.int32], npt.NDArray[np.int32], npt.NDArray[np.int32]]:
+        # We only care if the point are in the global grid (an error
+        # will be thrown if that is not the case).
+        _, p1_checked = self.check_point(p1, cmd_str, name="vertex_1")
+        _, p2_checked = self.check_point(p2, cmd_str, name="vertex_2")
+        _, p3_checked = self.check_point(p3, cmd_str, name="vertex_3")
 
-        return (
-            p1_within_grid and p2_within_grid and p3_within_grid,
-            p1_checked,
-            p2_checked,
-            p3_checked,
-        )
+        return p1_checked, p2_checked, p3_checked
 
     def check_thickness(
-        self, dimension: str, start: float, thickness: float
+        self,
+        dimension: str,
+        lower_extent: float,
+        thickness: float,
+        cmd_str: str,
     ) -> Tuple[bool, float, float]:
         """Check the thickness of an object in a specified dimension.
 
         Args:
             dimension: Dimension to check the thickness value for.
                 This must have value x, y, or z.
-            start: Start coordinate of the object in the specified
-                dimension. This must be in the local grid coordinate
-                system - i.e. previously translated using the
-                round_to_grid function.
+            lower_extent: Lower extent of the object in the specified
+                dimension.
             thickness: Thickness of the object.
 
         Raises:
@@ -231,35 +233,71 @@ class MainGridUserInput(UserInput[GridType]):
         Returns:
             within_grid: True if part of the object is within the
                 current grid. False otherwise.
-            start: Start value limited to the bounds of the grid.
-            thickness: Thickness value such that start + thickness is
-                within the bounds of the grid.
+            lower_extent: Lower extent limited to the bounds of the
+                grid.
+            thickness: Thickness value such that lower_extent +
+                thickness is within the bounds of the grid.
         """
-        # TODO: This should throw an error if the bounds are outside the
-        # global grid.
+        if thickness < 0:
+            raise ValueError(f"'{cmd_str}' requires a non negative thickness")
+
+        if lower_extent < 0:
+            raise ValueError(
+                f"'{cmd_str}' lower extent should be non negative in the {dimension} dimension"
+            )
+
+        upper_extent = lower_extent + thickness
+
         if dimension == "x":
-            grid_size = self.grid.nx * self.grid.dx
+            lower_point = self.discretise_point((lower_extent, 0, 0))
+            upper_point = self.discretise_point((upper_extent, 0, 0))
+            thickness_point = self.discretise_static_point((thickness, 0, 0))
+            index = 0
         elif dimension == "y":
-            grid_size = self.grid.ny * self.grid.dy
+            lower_point = self.discretise_point((0, lower_extent, 0))
+            upper_point = self.discretise_point((0, upper_extent, 0))
+            thickness_point = self.discretise_static_point((0, thickness, 0))
+            index = 1
         elif dimension == "z":
-            grid_size = self.grid.nz * self.grid.dz
+            lower_point = self.discretise_point((0, 0, lower_extent))
+            upper_point = self.discretise_point((0, 0, upper_extent))
+            thickness_point = self.discretise_static_point((0, 0, thickness))
+            index = 2
         else:
             raise ValueError("Dimension should have value x, y, or z")
 
-        end = start + thickness
+        try:
+            self.grid.within_bounds(upper_point)
+        except ValueError:
+            raise ValueError(
+                f"'{cmd_str}' extends beyond the size of the model in the {dimension} dimension"
+            )
 
-        if start > grid_size:
-            return False, start, thickness
-        elif end < 0:
-            return False, start, thickness
+        # Work with discretised (int) values as reduces imprecision due
+        # to floating point calculations
+        size = self.grid.size[index]
+        lower_extent = lower_point[index]
+        upper_extent = upper_point[index]
+        thickness = thickness_point[index]
 
-        if start < 0:
-            thickness += start
-            start = 0
-        if end > grid_size:
-            thickness -= end - grid_size
+        # These should only trigger for MPIGrids.
+        # TODO: Can this be structured so these checks happen in the
+        # MPIGridUserInput object?
+        if lower_extent < 0:
+            thickness += lower_extent
+            lower_extent = 0
+        if upper_extent > size:
+            thickness -= upper_extent - size
 
-        return True, start, thickness
+        dl = self.grid.dl[index]
+
+        return (
+            lower_extent <= size
+            and upper_extent >= 0
+            and not (upper_extent > size and thickness <= 0),
+            lower_extent * dl,
+            thickness * dl,
+        )
 
 
 class MPIUserInput(MainGridUserInput[MPIGrid]):

gprMax/user_objects/cmds_geometry/cylindrical_sector.py

@@ -90,7 +90,9 @@ class CylindricalSector(GeometryUserObject):
         elif normal == "z":
             ctr1, ctr2, level = uip.round_to_grid((ctr1, ctr2, extent1))
 
-        sector_within_grid, level, thickness = uip.check_thickness(normal, level, thickness)
+        sector_within_grid, level, thickness = uip.check_thickness(
+            normal, extent1, thickness, self.__str__()
+        )
 
         # Exit early if none of the cylindrical sector is in this grid
         # as there is nothing else to do.

gprMax/user_objects/cmds_geometry/triangle.py

@@ -96,37 +96,35 @@ class Triangle(RotatableMixin, GeometryUserObject):
                 logger.exception(f"{self.__str__()} no materials have been specified")
                 raise
 
-        if thickness < 0:
-            logger.exception(f"{self.__str__()} requires a positive value for thickness")
-            raise ValueError
-
         uip = self._create_uip(grid)
 
         # Check whether points are valid against grid
-        uip.check_tri_points(up1, up2, up3, self.__str__())
+        dp1, dp2, dp3 = uip.check_tri_points(up1, up2, up3, self.__str__())
         # Convert points to metres
-        x1, y1, z1 = uip.round_to_grid(up1)
-        x2, y2, z2 = uip.round_to_grid(up2)
-        x3, y3, z3 = uip.round_to_grid(up3)
+        x1, y1, z1 = uip.discrete_to_continuous(dp1)
+        x2, y2, z2 = uip.discrete_to_continuous(dp2)
+        x3, y3, z3 = uip.discrete_to_continuous(dp3)
 
         # Check for valid orientations
         # yz-plane triangle
         if x1 == x2 == x3:
             normal = "x"
-            start = x1
+            lower_extent = up1[0]
         # xz-plane triangle
         elif y1 == y2 == y3:
             normal = "y"
-            start = y1
+            lower_extent = up1[1]
         # xy-plane triangle
         elif z1 == z2 == z3:
             normal = "z"
-            start = z1
+            lower_extent = up1[2]
         else:
             logger.exception(f"{self.__str__()} the triangle is not specified correctly")
             raise ValueError
 
-        triangle_within_grid, start, thickness = uip.check_thickness(normal, start, thickness)
+        triangle_within_grid, lower_extent, thickness = uip.check_thickness(
+            normal, lower_extent, thickness, self.__str__()
+        )
 
         # Exit early if none of the triangle is in this grid as there is
         # nothing else to do.
@@ -136,19 +134,13 @@ class Triangle(RotatableMixin, GeometryUserObject):
         # Update start bound of the triangle
         # yz-plane triangle
         if normal == "x":
-            x1 = start
-            x2 = start
-            x3 = start
+            x1 = x2 = x3 = lower_extent
         # xz-plane triangle
         elif normal == "y":
-            y1 = start
-            y2 = start
-            y3 = start
+            y1 = y2 = y3 = lower_extent
         # xy-plane triangle
         elif normal == "z":
-            z1 = start
-            z2 = start
-            z3 = start
+            z1 = z2 = z3 = lower_extent
 
         # Look up requested materials in existing list of material instances
         materials = [y for x in materialsrequested for y in grid.materials if y.ID == x]

reframe_tests/tests/src/geometry_tests/cylindrical_sector_geometry/cylindrical_sector_z_outside_boundary.in

@@ -8,6 +8,6 @@
 #rx: 0.080 0.080 0.080
 
 #material: 8 0 1 0 half_space
-#cylindrical_sector: z 0.07 0.06 0.04 0.12 0.05 30 240 half_space
+#cylindrical_sector: z 0.07 0.06 0.04 0.1 0.05 30 240 half_space
 
 #geometry_objects_write: 0 0 0 0.1 0.1 0.1 full_volume