fixes issue #353 and adds a test

pyroomacoustics/room.py

@@ -2258,7 +2258,8 @@ def compute_rir(self):
 
                     # compute the distance from image sources
                     dist = np.sqrt(np.sum((src.images - mic[:, None]) ** 2, axis=0))
-                    time = dist / self.c
+                    # the RIR building routine works in float32, so we cast here
+                    time = (dist / self.c).astype(np.float32)
                     t_max = time.max()
                     N = int(math.ceil(t_max * self.fs))
 

pyroomacoustics/tests/test_issue_353.py

@@ -0,0 +1,43 @@
+"""
+# Test for Issue 353
+
+[issue #353](https://github.com/LCAV/pyroomacoustics/issues/353)
+
+The cause of the issue was that the time of the maximum delay
+in the RIR is used to determine the necessary size of the array.
+
+The float64 value of the delay was used to determine the size and construct the array.
+However, the `rir_build` routine takes float32.
+After conversion, the array size would evaluate to one delay more due to rounding
+offset and an array size check would fail.
+
+Converting the delay time array to float32 before creating the rir array
+solved the issue.
+"""
+import numpy as np
+import pyroomacoustics as pra
+
+
+def test_issue_353():
+    room_dims = np.array([10., 10., 10.])
+    room = pra.ShoeBox(
+            room_dims,
+            fs=24000,
+            materials=None,
+            max_order=22,
+            use_rand_ism=False
+    )
+
+    source = np.array([[6.35551912],[4.33308523], [3.69586303]])
+    room.add_source(source)
+
+    mic_array_in_room = np.array(
+        [
+            [1.5205189, 1.49366285, 1.73302404, 1.67847898],
+            [4.68430529, 4.76250254, 4.67956424, 4.60702604],
+            [2.68214263, 2.7980202,  2.55341851, 2.72701718]
+        ]
+    )
+    room.add_microphone_array(mic_array_in_room)
+
+    room.compute_rir()