Fix unauthorized inplace update of vector B in numba solve_triangular

pytensor/link/numba/dispatch/slinalg.py

@@ -126,13 +126,17 @@ def solve_triangular_impl(A, B, trans, lower, unit_diagonal, b_ndim, overwrite_b
 
         B_is_1d = B.ndim == 1
 
-        if not overwrite_b:
-            B_copy = _copy_to_fortran_order(B)
-        else:
+        if overwrite_b:
             B_copy = B
+        else:
+            if B_is_1d:
+                # _copy_to_fortran_order does nothing with vectors
+                B_copy = np.copy(B)
+            else:
+                B_copy = _copy_to_fortran_order(B)
 
         if B_is_1d:
-            B_copy = np.expand_dims(B, -1)
+            B_copy = np.expand_dims(B_copy, -1)
 
         NRHS = 1 if B_is_1d else int(B_copy.shape[-1])
 

tests/link/numba/test_slinalg.py

@@ -79,9 +79,9 @@ def test_solve_triangular(b_shape: tuple[int], lower, trans, unit_diag, is_compl
         A_val = A_val + np.random.normal(size=(5, 5)) * 1j
         b_val = b_val + np.random.normal(size=b_shape) * 1j
 
-    X_np = f(A_func(A_val.copy()), b_val.copy())
+    X_np = f(A_func(A_val), b_val)
 
-    test_input = transpose_func(A_func(A_val.copy()), trans)
+    test_input = transpose_func(A_func(A_val), trans)
 
     ATOL = 1e-8 if floatX.endswith("64") else 1e-4
     RTOL = 1e-8 if floatX.endswith("64") else 1e-4
@@ -92,7 +92,7 @@ def test_solve_triangular(b_shape: tuple[int], lower, trans, unit_diag, is_compl
     compare_numba_and_py(
         compiled_fgraph.inputs,
         compiled_fgraph.outputs,
-        [A_func(A_val.copy()), b_val.copy()],
+        [A_func(A_val), b_val],
     )