Update IsogonalOctagon to use xz basis and update tests (#3045)

openmc/model/surface_composite.py

@@ -233,23 +233,23 @@ class IsogonalOctagon(CompositeSurface):
     r"""Infinite isogonal octagon composite surface
 
     An isogonal octagon is composed of eight planar surfaces. The prism is
-    parallel to the x, y, or z axis. The remaining two axes (y and z, z and x,
+    parallel to the x, y, or z axis. The remaining two axes (y and z, x and z,
     or x and y) serve as a basis for constructing the surfaces. Two surfaces
     are parallel to the first basis axis, two surfaces are parallel
     to the second basis axis, and the remaining four surfaces intersect both
     basis axes at 45 degree angles.
 
     This class acts as a proper surface, meaning that unary `+` and `-`
     operators applied to it will produce a half-space. The negative side is
-    defined to be the region inside of the octogonal prism.
+    defined to be the region inside of the octagonal prism.
 
     .. versionadded:: 0.13.1
 
     Parameters
     ----------
     center : iterable of float
         Coordinate for the central axis of the octagon in the
-        (y, z), (z, x), or (x, y) basis.
+        (y, z), (x, z), or (x, y) basis depending on the axis parameter.
     r1 : float
         Half-width of octagon across its basis axis-parallel sides in units
         of cm. Must be less than :math:`r_2\sqrt{2}`.
@@ -290,7 +290,7 @@ class IsogonalOctagon(CompositeSurface):
     def __init__(self, center, r1, r2, axis='z', **kwargs):
         c1, c2 = center
 
-        # Coords for axis-perpendicular planes
+        # Coordinates for axis-perpendicular planes
         cright = c1 + r1
         cleft = c1 - r1
 
@@ -307,7 +307,7 @@ def __init__(self, center, r1, r2, axis='z', **kwargs):
 
         L_basis_ax = (r2 * sqrt(2) - r1)
 
-        # Coords for quadrant planes
+        # Coordinates for quadrant planes
         p1_ur = np.array([L_basis_ax, r1, 0.])
         p2_ur = np.array([r1, L_basis_ax, 0.])
         p3_ur = np.array([r1, L_basis_ax, 1.])
@@ -335,17 +335,18 @@ def __init__(self, center, r1, r2, axis='z', **kwargs):
             self.right = openmc.XPlane(cright, **kwargs)
             self.left = openmc.XPlane(cleft, **kwargs)
         elif axis == 'y':
-            coord_map = [1, 2, 0]
-            self.top = openmc.XPlane(ctop, **kwargs)
-            self.bottom = openmc.XPlane(cbottom, **kwargs)
-            self.right = openmc.ZPlane(cright, **kwargs)
-            self.left = openmc.ZPlane(cleft, **kwargs)
+            coord_map = [0, 2, 1]
+            self.top = openmc.ZPlane(ctop, **kwargs)
+            self.bottom = openmc.ZPlane(cbottom, **kwargs)
+            self.right = openmc.XPlane(cright, **kwargs)
+            self.left = openmc.XPlane(cleft, **kwargs)
         elif axis == 'x':
             coord_map = [2, 0, 1]
             self.top = openmc.ZPlane(ctop, **kwargs)
             self.bottom = openmc.ZPlane(cbottom, **kwargs)
             self.right = openmc.YPlane(cright, **kwargs)
             self.left = openmc.YPlane(cleft, **kwargs)
+        self.axis = axis
 
         # Put our coordinates in (x,y,z) order and add the offset
         for p in points:
@@ -363,14 +364,27 @@ def __init__(self, center, r1, r2, axis='z', **kwargs):
                                                    **kwargs)
 
     def __neg__(self):
-        return -self.top & +self.bottom & -self.right & +self.left & \
-            +self.upper_right & +self.lower_right & -self.lower_left & \
-            -self.upper_left
+        if self.axis == 'y':
+            region = -self.top & +self.bottom & -self.right & +self.left & \
+                -self.upper_right & -self.lower_right & +self.lower_left & \
+                +self.upper_left
+        else:
+            region = -self.top & +self.bottom & -self.right & +self.left & \
+                +self.upper_right & +self.lower_right & -self.lower_left & \
+                -self.upper_left
+
+        return region
 
     def __pos__(self):
-        return +self.top | -self.bottom | +self.right | -self.left | \
-            -self.upper_right | -self.lower_right | +self.lower_left | \
-            +self.upper_left
+        if self.axis == 'y':
+            region = +self.top | -self.bottom | +self.right | -self.left | \
+                +self.upper_right | +self.lower_right | -self.lower_left | \
+                -self.upper_left
+        else:
+            region = +self.top | -self.bottom | +self.right | -self.left | \
+                -self.upper_right | -self.lower_right | +self.lower_left | \
+                +self.upper_left
+        return region
 
 
 class RightCircularCylinder(CompositeSurface):

tests/unit_tests/test_surface_composite.py

@@ -255,7 +255,7 @@ def test_cylinder_sector_from_theta_alpha():
 @pytest.mark.parametrize(
     "axis, plane_tb, plane_lr, axis_idx", [
         ("x", "Z", "Y", 0),
-        ("y", "X", "Z", 1),
+        ("y", "Z", "X", 1),
         ("z", "Y", "X", 2),
     ]
 )