diff --git a/src/irp_stack.py b/src/irp_stack.py
index b9cc9f9..9a90f9c 100644
--- a/src/irp_stack.py
+++ b/src/irp_stack.py
@@ -185,9 +185,9 @@ end subroutine
       s += """
  nthread = 1
  if (.not.alloc) then
-   allocate(irp_stack(0:STACKMAX,1))
-   allocate(irp_cpu(0:STACKMAX,1))
-   allocate(stack_index(2))
+   allocate(irp_stack(0:STACKMAX,0:1))
+   allocate(irp_cpu(0:STACKMAX,0:1))
+   allocate(stack_index(0:2))
    stack_index = 0
    alloc = .True.
  endif