fix non-positive determinant error in tests/scipy_spatial_test.py::...::testRotationFromMatrix0 (#362)

Co-authored-by: Jake VanderPlas <[email protected]>

Author: gulsumgudukbay

tests/scipy_spatial_test.py

@@ -196,7 +196,10 @@ def testRotationFromEuler(self, size, dtype, seq, degrees):
   )
   def testRotationFromMatrix(self, shape, dtype):
     rng = jtu.rand_default(self.rng())
-    args_maker = lambda: (rng(shape, dtype),)
+    def args_maker():
+      # Use QR to ensure valid positive-definite rotation matrix.
+      q, _ = onp.linalg.qr(rng(shape, dtype))
+      return [q]
     jnp_fn = lambda m: jsp_Rotation.from_matrix(m).as_rotvec()
     np_fn = lambda m: osp_Rotation.from_matrix(m).as_rotvec().astype(dtype)
     self._CheckAgainstNumpy(np_fn, jnp_fn, args_maker, check_dtypes=True, tol=1e-4)