aesara-devs · jessegrabowski · Jun 29, 2022 · Jun 29, 2022 · Jun 30, 2022 · Jun 30, 2022
diff --git a/aesara/tensor/basic.py b/aesara/tensor/basic.py
@@ -1284,7 +1284,7 @@ def grad(self, inp, grads):
         return [grad_undefined(self, i, inp[i]) for i in range(3)]
 
 
-def eye(n, m=None, k=0, dtype=None):
+def eye(n: int, m: int = None, k: int = 0, dtype=None) -> TensorVariable:
     """Return a 2-D array with ones on the diagonal and zeros elsewhere.
 
     Parameters
@@ -1302,17 +1302,41 @@ def eye(n, m=None, k=0, dtype=None):
 
     Returns
     -------
-    ndarray of shape (N,M)
-        An array where all elements are equal to zero, except for the `k`-th
-        diagonal, whose values are equal to one.
-
+    aesara tensor of shape (N,M)
+        A symbolic tensor representing a matrix where all elements are equal to zero,
+        except for the `k`-th diagonal, whose values are equal to one.
     """
-    if dtype is None:
-        dtype = config.floatX
+
     if m is None:
         m = n
-    localop = Eye(dtype)
-    return localop(n, m, k)
+    if dtype is None:
+        dtype = aesara.config.floatX
+
+    n = aesara.scalar.as_scalar(n)
+    m = aesara.scalar.as_scalar(m)
+    k = aesara.scalar.as_scalar(k)
+
+    i = aesara.scalar.switch(k >= 0, k, -k * m)
+    i_comp_op = aesara.scalar.Composite([n, m, k], [i])
+    i_comp = i_comp_op(n, m, k)
+
+    mkm = (m - k) * m
+    mkm_comp_op = aesara.scalar.Composite([m, k], [mkm])
+    mkm_comp = mkm_comp_op(m, k)
+
+    last_row = aesara.scalar.switch(m - k > 0, m - k, 0)
+    last_row_op = aesara.scalar.Composite([m, k], [last_row])
+    last_valid_row = last_row_op(m, k)
+
+    eye = zeros(n * m, dtype=dtype)
+
+    ones_slice = slice(i_comp, mkm_comp, m + 1)
+    overflow_rows = slice(last_valid_row, None, None)
+
+    eye = aesara.tensor.subtensor.set_subtensor(eye[ones_slice], 1).reshape((n, m))
+    eye = aesara.tensor.subtensor.set_subtensor(eye[overflow_rows, :], 0)
+
+    return eye
 
 
 def identity_like(x, dtype: Optional[Union[str, np.generic, np.dtype]] = None):

diff --git a/tests/tensor/test_basic.py b/tests/tensor/test_basic.py
@@ -822,11 +822,14 @@ def check(dtype, N, M_=None, k=0):
         # allowed.
         if M is None and config.mode in ["DebugMode", "DEBUG_MODE"]:
             M = N
+
         N_symb = iscalar()
         M_symb = iscalar()
         k_symb = iscalar()
+
         f = function([N_symb, M_symb, k_symb], eye(N_symb, M_symb, k_symb, dtype=dtype))
         result = f(N, M, k)
+
         assert np.allclose(result, np.eye(N, M_, k, dtype=dtype))
         assert result.dtype == np.dtype(dtype)