Minor fix to mesh generator (#430)

* modify mesh generator to accept even nx

* fixed ref of chordwise coordinate for rectangle wings

* vsp test fix

* formatting

* formatting

* minor edits to GHA yml

* Use newer codecov version in GHA

* Whack the chunk adaptation

* clean up

---------

Co-authored-by: Eytan Adler <eytana@umich.edu>

Author: kanekosh

.github/workflows/oas.yml

@@ -20,6 +20,7 @@ jobs:
   test:
     runs-on: ubuntu-latest
     strategy:
+      fail-fast: false  # continue other jobs even if one of the jobs in matrix fails 
       matrix:
         dep-versions: ["oldest", "latest"]
         # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Set versions to test here ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -163,12 +164,13 @@ jobs:
         coverage xml
 
     - name: Upload Coverage to Codecov
-      uses: codecov/codecov-action@v3
+      uses: codecov/codecov-action@v4
       with:
         fail_ci_if_error: true
-        token: ${{ secrets.CODECOV_TOKEN }}
         verbose: true
-        
+      env:
+        CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
+
   # --- linting and formatting ---
   black:
     uses: mdolab/.github/.github/workflows/black.yaml@main

openaerostruct/__init__.py

@@ -1 +1 @@
-__version__ = "2.7.1"
+__version__ = "2.7.2"

openaerostruct/docs/user_reference/mesh_surface_dict.rst

@@ -19,7 +19,7 @@ Here is a list of the keys and default values of the ``mesh_dict``, which is use
     * - num_x
       - 3
       - 
-      - Number of chordwise vertices. Needs to be 2 or an odd number.
+      - Number of chordwise vertices.
     * - num_y
       - 5
       - 

openaerostruct/geometry/tests/test_vsp_mesh.py

@@ -27,6 +27,7 @@ def test_full(self):
             "span": 10.0,
             "root_chord": 1,
             "span_cos_spacing": 0.0,
+            "offset": [-0.5, 0, 0],  # chordwise coordinate goes from -0.5 to 0.5
         }
 
         oas_mesh = generate_mesh(mesh_dict)
@@ -46,6 +47,7 @@ def test_symm(self):
             "span": 10.0,
             "root_chord": 1,
             "span_cos_spacing": 0.0,
+            "offset": [-0.5, 0, 0],  # chordwise coordinate goes from -0.5 to 0.5
         }
 
         oas_mesh = generate_mesh(mesh_dict)

openaerostruct/geometry/utils.py

@@ -375,6 +375,7 @@ def gen_rect_mesh(num_x, num_y, span, chord, span_cos_spacing=0.0, chord_cos_spa
     mesh = np.zeros((num_x, num_y, 3))
     ny2 = (num_y + 1) // 2
 
+    # --- spanwise discretization ---
     # Hotfix a special case for spacing bunched at the root and tips
     if span_cos_spacing == 2.0:
         beta = np.linspace(0, np.pi, ny2)
@@ -396,23 +397,17 @@ def gen_rect_mesh(num_x, num_y, span, chord, span_cos_spacing=0.0, chord_cos_spa
         half_wing = cosine * span_cos_spacing + (1 - span_cos_spacing) * uniform
         full_wing = np.hstack((-half_wing[:-1], half_wing[::-1])) * span
 
-    nx2 = (num_x + 1) // 2
-    beta = np.linspace(0, np.pi / 2, nx2)
-
-    # mixed spacing with span_cos_spacing as a weighting factor
-    # this is for the chordwise spacing
-    cosine = 0.5 * np.cos(beta)  # cosine spacing
-    uniform = np.linspace(0, 0.5, nx2)[::-1]  # uniform spacing
-    half_wing = cosine * chord_cos_spacing + (1 - chord_cos_spacing) * uniform
-    full_wing_x = np.hstack((-half_wing[:-1], half_wing[::-1])) * chord
-
-    # Special case if there are only 2 chordwise nodes
-    if num_x <= 2:
-        full_wing_x = np.array([0.0, chord])
+    # --- chordwise discretization ---
+    cosine = 0.5 * (1 - np.cos(np.linspace(0, np.pi, num_x)))  # cosine spacing from 0 to 1
+    uniform = np.linspace(0, 1, num_x)  # uniform spacing
+    # mixed spacing with chord_cos_spacing as a weighting factor
+    wing_x = cosine * chord_cos_spacing + (1 - chord_cos_spacing) * uniform
+    wing_x *= chord  # apply chord length
 
+    # --- form 3D mesh array ---
     for ind_x in range(num_x):
         for ind_y in range(num_y):
-            mesh[ind_x, ind_y, :] = [full_wing_x[ind_x], full_wing[ind_y], 0]
+            mesh[ind_x, ind_y, :] = [wing_x[ind_x], full_wing[ind_y], 0]
 
     return mesh
 
@@ -557,24 +552,12 @@ def add_chordwise_panels(mesh, num_x, chord_cos_spacing):
 
     # Obtain mesh and num properties
     num_y = mesh.shape[1]
-    nx2 = (num_x + 1) // 2
-
-    # Create beta, an array of linear sampling points to pi/2
-    beta = np.linspace(0, np.pi / 2, nx2)
-
-    # Obtain the two spacings that we will use to blend
-    cosine = 0.5 * np.cos(beta)  # cosine spacing
-    uniform = np.linspace(0, 0.5, nx2)[::-1]  # uniform spacing
-
-    # Create half of the wing in the chordwise direction
-    half_wing = cosine * chord_cos_spacing + (1 - chord_cos_spacing) * uniform
 
-    if chord_cos_spacing == 0.0:
-        full_wing_x = np.linspace(0, 1.0, num_x)
-
-    else:
-        # Mirror this half wing into a full wing; offset by 0.5 so it goes 0 to 1
-        full_wing_x = np.hstack((-half_wing[:-1], half_wing[::-1])) + 0.5
+    # chordwise discretization
+    cosine = 0.5 * (1 - np.cos(np.linspace(0, np.pi, num_x)))  # cosine spacing from 0 to 1
+    uniform = np.linspace(0, 1, num_x)  # uniform spacing
+    # mixed spacing with chord_cos_spacing as a weighting factor
+    wing_x = cosine * chord_cos_spacing + (1 - chord_cos_spacing) * uniform
 
     # Obtain the leading and trailing edges
     le = mesh[0, :, :]
@@ -586,7 +569,7 @@ def add_chordwise_panels(mesh, num_x, chord_cos_spacing):
     new_mesh[-1, :, :] = te
 
     for i in range(1, num_x - 1):
-        w = full_wing_x[i]
+        w = wing_x[i]
         new_mesh[i, :, :] = (1 - w) * le + w * te
 
     return new_mesh
@@ -635,6 +618,29 @@ def get_default_geo_dict():
 
 
 def generate_mesh(input_dict):
+    """
+    Generate an OAS mesh.
+
+    Parameters
+    ----------
+    input_dict : dict
+        Dictionary containing user-provided parameters for the surface definition.
+        See the following for more information:
+        https://mdolab-openaerostruct.readthedocs-hosted.com/en/latest/user_reference/mesh_surface_dict.html#mesh-dict
+
+    Returns
+    -------
+    mesh : numpy array
+        Nodal coordinates defining the mesh.
+        shape = (nx, ny, 3),
+        where nx is the number of chordwise discretization nodes, ny is the number of spanwise discretization nodes.
+        If input_dict["symmetry"] is True, mesh defines left half of wing.
+    twist : numpy array, optional
+        Only for CRM wing (input_dict["wing_type"] == "CRM").
+        Twist values at the spanwise locations.
+
+    """
+
     # Get defaults and update surface with the user-provided input
     surf_dict = get_default_geo_dict()
 
@@ -677,10 +683,6 @@ def generate_mesh(input_dict):
     if not num_y % 2:
         raise ValueError("num_y must be an odd number.")
 
-    # Check to make sure that an odd number of chordwise points (num_x) was provided
-    if not num_x % 2 and not num_x == 2:
-        raise ValueError("num_x must be an odd number.")
-
     # Generate rectangular mesh
     if surf_dict["wing_type"] == "rect":
         span = surf_dict["span"]

openaerostruct/tests/test_multiple_rect.py

@@ -44,7 +44,13 @@ def test(self):
         }
 
         # Create a dictionary to store options about the surface
-        mesh_dict = {"num_y": 5, "num_x": 3, "wing_type": "rect", "symmetry": True, "offset": np.array([50, 0.0, 0.0])}
+        mesh_dict = {
+            "num_y": 5,
+            "num_x": 3,
+            "wing_type": "rect",
+            "symmetry": True,
+            "offset": np.array([49.5, 0.0, 0.0]),
+        }
 
         mesh = generate_mesh(mesh_dict)
 

openaerostruct/tests/test_scaneagle.py

@@ -115,7 +115,7 @@ def test(self):
         indep_var_comp.add_output("W0", val=10.0, units="kg")
         indep_var_comp.add_output("speed_of_sound", val=322.2, units="m/s")
         indep_var_comp.add_output("load_factor", val=1.0)
-        indep_var_comp.add_output("empty_cg", val=np.array([0.2, 0.0, 0.0]), units="m")
+        indep_var_comp.add_output("empty_cg", val=np.array([0.35, 0.0, 0.0]), units="m")
 
         prob.model.add_subsystem("prob_vars", indep_var_comp, promotes=["*"])
 

openaerostruct/tests/test_struct_point_masses.py

@@ -11,7 +11,7 @@
 class Test(unittest.TestCase):
     def test(self):
         # Create a dictionary to store options about the surface
-        mesh_dict = {"num_y": 31, "wing_type": "rect", "span": 10, "symmetry": True}
+        mesh_dict = {"num_y": 31, "num_x": 3, "wing_type": "rect", "span": 10, "symmetry": True}
 
         mesh = generate_mesh(mesh_dict)
 
@@ -48,7 +48,7 @@ def test(self):
 
         point_masses = np.array([[10.0]])
 
-        point_mass_locations = np.array([[1.0, -10.0, 0.0]])
+        point_mass_locations = np.array([[1.5, -10.0, 0.0]])
 
         indep_var_comp.add_output("point_masses", val=point_masses, units="kg")
         indep_var_comp.add_output("point_mass_locations", val=point_mass_locations, units="m")
@@ -69,7 +69,7 @@ def test(self):
 
     def test_multiple_masses(self):
         # Create a dictionary to store options about the surface
-        mesh_dict = {"num_y": 31, "wing_type": "rect", "span": 10, "symmetry": True}
+        mesh_dict = {"num_y": 31, "num_x": 3, "wing_type": "rect", "span": 10, "symmetry": True}
 
         mesh = generate_mesh(mesh_dict)
 
@@ -106,7 +106,7 @@ def test_multiple_masses(self):
 
         point_masses = np.array([[10.0, 20.0]])
 
-        point_mass_locations = np.array([[1.0, -1.0, 0.0], [1.0, -2.0, 0.0]])
+        point_mass_locations = np.array([[1.5, -1.0, 0.0], [1.5, -2.0, 0.0]])
 
         indep_var_comp.add_output("point_masses", val=point_masses, units="kg")
         indep_var_comp.add_output("point_mass_locations", val=point_mass_locations, units="m")