This opinion will be endorsed by any European who reads through the book with an impartial spirit and some knowledge of the language, without taking into account the tiresome effect of its endless iterations.
Some models may require many more iterations to converge properly than others.
To detect simple cycles a threshold is set on the number of consecutive iterations during which the same numbers of elements have moved.
These are the block (or interleaver) size, the encoder constraint length and the number of decoder iterations performed.
If X or N are arrays, ITER will contain a scalar representing the maximum number of iterations.