diff --git a/cij/misc/evec_disp2eig.py b/cij/misc/evec_disp2eig.py
index 4b0f0a2..361500d 100644
--- a/cij/misc/evec_disp2eig.py
+++ b/cij/misc/evec_disp2eig.py
@@ -17,13 +17,10 @@ def evec_disp2eig(a: numpy.ndarray, mass: list) -> numpy.ndarray:
     This function returns normalized :math:`\\left|C_i^m\\right>`.
 
 
-    :param a: 3N x 1 displacement vector or 3N x 3N displacement vector matrix
+    :param a: M x 3N displacement vector matrix
     :param mass: N x 1 atom mass vector, of any unit
 
-    :returns: Eigenvector matrix, shape determined by the shape of ``a``:
-
-        * If ``a`` is a displacement vector, return a 3N x 1 eigenvector
-        * If ``a`` is a displacement matrix, return a 3N x 3N eigenvector matrix
+    :returns: Eigenvector matrix, shape is same as ``a`` (M x 3N):
     '''
 
     N = len(mass) # number of atoms
@@ -31,18 +28,7 @@ def evec_disp2eig(a: numpy.ndarray, mass: list) -> numpy.ndarray:
     m = numpy.repeat(mass, 3)   # Account for 3 polarization directions, N -> 3N
     a = numpy.copy(a)
 
-    if a.shape == (3*N,):
-
-        # Multiply by mass matrix
-
-        a *= numpy.sqrt(m)
-
-        # Renormalization
-
-        norm = numpy.conj(a) @ a.T
-        a /= numpy.sqrt(norm)
-
-    elif a.shape == (3*N, 3*N):
+    if a.shape[1] == 3*N:
 
         # Multiply by mass matrix
 
diff --git a/tests/test_cij_misc_evec_load.py b/tests/test_cij_misc_evec_load.py
index 27e6ea8..451e36a 100644
--- a/tests/test_cij_misc_evec_load.py
+++ b/tests/test_cij_misc_evec_load.py
@@ -52,7 +52,7 @@ def mass():
     return mass
 
 @pytest.mark.parametrize("nq, nbnd", [(2, 60)])
-def test_evec_dispvec_disp2eig_vector_version(nq, nbnd, mass):
+def test_evec_dispvec_disp2eig_3Nx3N(nq, nbnd, mass):
 
     vecs = evec_load(Path(__file__).parent / "data" / test_files["vec"], nq, nbnd)
     eigs = evec_load(Path(__file__).parent / "data" / test_files["eig"], nq, nbnd)
@@ -70,7 +70,7 @@ def test_evec_dispvec_disp2eig_vector_version(nq, nbnd, mass):
 
 
 @pytest.mark.parametrize("nq, nbnd", [(2, 60)])
-def test_evec_dispvec_disp2eig_matrix_version(nq, nbnd, mass):
+def test_evec_dispvec_disp2eig_1x3N(nq, nbnd, mass):
 
     vecs = evec_load(Path(__file__).parent / "data" / test_files["vec"], nq, nbnd)
     eigs = evec_load(Path(__file__).parent / "data" / test_files["eig"], nq, nbnd)
@@ -85,8 +85,8 @@ def test_evec_dispvec_disp2eig_matrix_version(nq, nbnd, mass):
 
         for ibnd in range(nbnd):
 
-            a1 = numpy.array(vecs[iq][1][ibnd][1])
-            a2 = numpy.array(eigs[iq][1][ibnd][1])
+            a1 = numpy.array([vecs[iq][1][ibnd][1]])
+            a2 = numpy.array([eigs[iq][1][ibnd][1]])
             a1 = evec_disp2eig(a1, mass)
 
-            assert numpy.allclose(a1, a2, atol=1e-4)
+            assert numpy.allclose(a1[0], a2, atol=1e-4)