Use actual Solve Op to infer output dtype

CholSolve outputs a different dtype than basic Solve in Scipy==1.15

Author: ricardoV94

pytensor/tensor/slinalg.py

@@ -259,9 +259,10 @@ def make_node(self, A, b):
             raise ValueError(f"`b` must have {self.b_ndim} dims; got {b.type} instead.")
 
         # Infer dtype by solving the most simple case with 1x1 matrices
-        o_dtype = scipy.linalg.solve(
-            np.eye(1).astype(A.dtype), np.eye(1).astype(b.dtype)
-        ).dtype
+        inp_arr = [np.eye(1).astype(A.dtype), np.eye(1).astype(b.dtype)]
+        out_arr = [[None]]
+        self.perform(None, inp_arr, out_arr)
+        o_dtype = out_arr[0][0].dtype
         x = tensor(dtype=o_dtype, shape=b.type.shape)
         return Apply(self, [A, b], [x])
 

tests/tensor/test_slinalg.py

@@ -450,7 +450,7 @@ def test_solve_dtype(self):
             fn = function([A, b], x)
             x_result = fn(A_val.astype(A_dtype), b_val.astype(b_dtype))
 
-            assert x.dtype == x_result.dtype
+            assert x.dtype == x_result.dtype, (A_dtype, b_dtype)
 
 
 def test_cho_solve():