Fixes from_corner/extrude for mixed single/multi-band materials (#388)

Fixes a bug where the single/multi-band materials is not properly handled when using from_corners together with extrude. (issue #381)

CHANGELOG.rst

@@ -18,6 +18,12 @@ Bugfix
   directivity to ``Room.add_microphone_array``, the directivity was dropped
   from the object.
 
+- Fixes issues #381: When creating a room with from_corners with multi-band
+  material, and then making it 3D with ``extrude`` with a single band material
+  for the floor and ceiling, an error would occur.
+  After the fix, the materials for floor and ceiling are automatically extended
+  to multi-band, as expected.
+
 - Fixes issue #380: Caused by the attribute ``cartesian`` of ``GridSphere`` not
   being set properly when the grid is only initialized with a number of points.
 
@@ -30,7 +36,7 @@ Bugfix
 Changed
 ~~~~~~~
 
-- Makes the ``pyroomacoustics.utilities.resample`` backend is made configurable
+- Makes the ``pyroomacoustics.utilities.resample`` backend configurable
   to avoid ``soxr`` dependency. The resample backend is configurable to
   ``soxr``, ``samplerate``, if these packages are available, and otherwise
   falls back to ``scipy.signal.resample_poly``.

pyroomacoustics/room.py

@@ -1395,24 +1395,45 @@ def extrude(self, height, v_vec=None, absorption=None, materials=None):
         if libroom.area_2d_polygon(floor_corners) <= 0:
             floor_corners = np.fliplr(floor_corners)
 
-        walls = []
+        wall_corners = {}
+        wall_materials = {}
         for i in range(nw):
-            corners = np.array(
+            name = str(i)
+            wall_corners[name] = np.array(
                 [
                     np.r_[floor_corners[:, i], 0],
                     np.r_[floor_corners[:, (i + 1) % nw], 0],
                     np.r_[floor_corners[:, (i + 1) % nw], 0] + height * v_vec,
                     np.r_[floor_corners[:, i], 0] + height * v_vec,
                 ]
             ).T
-            walls.append(
-                wall_factory(
-                    corners,
-                    self.walls[i].absorption,
-                    self.walls[i].scatter,
-                    name=str(i),
+
+            if len(self.walls[i].absorption) == 1:
+                # Single band
+                wall_materials[name] = Material(
+                    energy_absorption=float(self.walls[i].absorption),
+                    scattering=float(self.walls[i].scatter),
+                )
+            elif len(self.walls[i].absorption) == self.octave_bands.n_bands:
+                # Multi-band
+                abs_dict = {
+                    "coeffs": self.walls[i].absorption,
+                    "center_freqs": self.octave_bands.centers,
+                    "description": "",
+                }
+                sca_dict = {
+                    "coeffs": self.walls[i].scatter,
+                    "center_freqs": self.octave_bands.centers,
+                    "description": "",
+                }
+                wall_materials[name] = Material(
+                    energy_absorption=abs_dict,
+                    scattering=sca_dict,
+                )
+            else:
+                raise ValueError(
+                    "Encountered a material with inconsistent number of bands."
                 )
-            )
 
         ############################
         # BEGIN COMPATIBILITY CODE #
@@ -1477,12 +1498,23 @@ def extrude(self, height, v_vec=None, absorption=None, materials=None):
         # we need the floor corners to ordered clockwise (for the normal to point outward)
         new_corners["floor"] = np.fliplr(new_corners["floor"])
 
-        for key in ["floor", "ceiling"]:
+        # Concatenate new walls param with old ones.
+        wall_corners.update(new_corners)
+        wall_materials.update(materials)
+
+        # If some of the materials used are multi-band, we need to resample
+        # all of them to have the same number of values
+        if not Material.all_flat(wall_materials):
+            for name, mat in wall_materials.items():
+                mat.resample(self.octave_bands)
+
+        walls = []
+        for key, corners in wall_corners.items():
             walls.append(
                 wall_factory(
-                    new_corners[key],
-                    materials[key].absorption_coeffs,
-                    materials[key].scattering_coeffs,
+                    corners,
+                    wall_materials[key].absorption_coeffs,
+                    wall_materials[key].scattering_coeffs,
                     name=key,
                 )
             )

pyroomacoustics/tests/test_from_corners_extrude.py

@@ -0,0 +1,68 @@
+import numpy as np
+import pytest
+
+import pyroomacoustics as pra
+
+_FS = 16000
+_MAX_ORDER = 3
+
+
+def test_from_corner_extrude():
+
+    room_dim = [3, 4, 5]
+    # This test is sensitive to the selection of this value.
+    # If some symmetries are present, for some reasons differences between
+    # the two simulated methods happen.
+    src_loc = [1.001, 0.999, 1.002]
+    mic_loc = [2, 3, 4]
+    mat = pra.Material(energy_absorption=0.1)
+
+    room_ref = pra.ShoeBox(room_dim, fs=_FS, max_order=_MAX_ORDER, materials=mat)
+    room_ref.add_source(src_loc).add_microphone(mic_loc)
+    room_ref.compute_rir()
+
+    # Now construct the same room with the other set of primitives.
+    corners = np.array(
+        [[0, 0], [room_dim[0], 0], [room_dim[0], room_dim[1]], [0, room_dim[1]]]
+    ).T
+    room = pra.Room.from_corners(corners, fs=_FS, max_order=_MAX_ORDER, materials=mat)
+    room.extrude(height=room_dim[2], materials=mat)
+    room.add_source(src_loc).add_microphone(mic_loc)
+    room.compute_rir()
+
+    assert np.allclose(room_ref.rir[0][0], room.rir[0][0], rtol=1e-4, atol=1e-4)
+
+
+def test_from_corner_extrude_different_materials():
+
+    room_dim = [3, 4, 5]
+    # This test is sensitive to the selection of this value.
+    # If some symmetries are present, for some reasons differences between
+    # the two simulated methods happen.
+    src_loc = [1.001, 0.999, 1.002]
+    mic_loc = [2, 3, 4]
+    mat1 = "hard_surface"
+    mat2 = 0.1
+
+    materials = pra.make_materials(
+        east=mat1, west=mat1, south=mat1, north=mat1, floor=mat2, ceiling=mat2
+    )
+    room_ref = pra.ShoeBox(room_dim, fs=_FS, max_order=_MAX_ORDER, materials=materials)
+    room_ref.add_source(src_loc).add_microphone(mic_loc)
+    room_ref.compute_rir()
+
+    # Now construct the same room with the other set of primitives.
+    corners = np.array(
+        [[0, 0], [room_dim[0], 0], [room_dim[0], room_dim[1]], [0, room_dim[1]]]
+    ).T
+    room = pra.Room.from_corners(
+        corners,
+        fs=_FS,
+        max_order=_MAX_ORDER,
+        materials=pra.Material(energy_absorption=mat1),
+    )
+    room.extrude(height=room_dim[2], materials=pra.Material(energy_absorption=mat2))
+    room.add_source(src_loc).add_microphone(mic_loc)
+    room.compute_rir()
+
+    assert np.allclose(room_ref.rir[0][0], room.rir[0][0], rtol=1e-4, atol=1e-4)