Fix LU P out dtype for complex input

Author: ricardoV94

pytensor/tensor/slinalg.py

@@ -508,7 +508,12 @@ def make_node(self, x):
             p_indices = tensor(shape=(x.type.shape[0],), dtype="int32")
             return Apply(self, inputs=[x], outputs=[p_indices, L, U])
 
-        P = tensor(shape=x.type.shape, dtype=out_dtype)
+        if out_dtype.startswith("complex"):
+            P_dtype = "float64" if out_dtype == "complex128" else "float32"
+        else:
+            P_dtype = out_dtype
+
+        P = tensor(shape=x.type.shape, dtype=P_dtype)
         return Apply(self, inputs=[x], outputs=[P, L, U])
 
     def perform(self, node, inputs, outputs):

tests/tensor/test_slinalg.py

@@ -648,16 +648,18 @@ def test_lu_decomposition(
     dtype = config.floatX if not complex else f"complex{int(config.floatX[-2:]) * 2}"
 
     A = tensor("A", shape=shape, dtype=dtype)
-    out = lu(A, permute_l=permute_l, p_indices=p_indices)
+    pt_out = lu(A, permute_l=permute_l, p_indices=p_indices)
 
-    f = function([A], out)
+    f = function([A], pt_out)
 
     rng = np.random.default_rng(utt.fetch_seed())
     x = rng.normal(size=shape).astype(config.floatX)
     if complex:
         x = x + 1j * rng.normal(size=shape).astype(config.floatX)
 
     out = f(x)
+    for numerical_out, symbolic_out in zip(out, pt_out):
+        assert numerical_out.dtype == symbolic_out.type.dtype
 
     if permute_l:
         PL, U = out