[CppAD] overflow of tape id when using many tapes

[Brad Bell]

The type corresponding to CppAD tape ids is now a configuration 
argument. See the heading tape_id_type in
     http://www.coin-or.org/CppAD/Doc/installunix.xml#tape_id_type

On 07/03/2012 06:28 AM, Stefan Vigerske wrote:
> Hi,
>
> changing the CPPAD_TAPE_ID_TYPE to size_t seem to have helped in my 
> case. We now could run until we hit our timelimit :-).
>
> Stefan
>
> On 07/01/2012 05:56 PM, Brad Bell wrote:
>> Thanks for the bug report I wondered if this would ever happen, and now
>> it has.
>>
>> I think that a good solution will be to maintain a list of active tapes.
>> I will look into it and get back to you.
>>
>> Brad.
>>
>>
>> On 07/01/2012 03:25 AM, Stefan Vigerske wrote:
>>> Hi, .
>>>
>>> in my code I use CppAD to evaluate function values and derivatives in
>>> many different places.
>>> For that, it is easier to create a new tape for each function.
>>> When the program runs a while (say, 8 hours), I seem to get an
>>> overflow in the tape_id, because CppAD seem to assign the id's with
>>> increasing numbers but does not reuse id's of tapes that are no longer
>>> in use.
>>>
>>> Originally, I had set CPPAD_MAX_NUM_THREADS to 48, which already gave
>>> a failure after 4 hours. When setting it to a power of 2, it works
>>> better, because after an overflow the tapeid is at a 0 again.
>>> However, changing CPPAD_MAX_NUM_THREADS to 1 does not seem to help 
>>> much.
>>> Actually, the last tape id before I get a segmentation fault is
>>> 8173126, which is even far below the maximum for an unsigned int.
>>> I'm now trying with CPPAD_TAPE_ID_TYPE changed to size_t.
>>>
>>> Anyhow, is there some better solution on how to use many tapes (but
>>> not all at the same time) in a longrunning program?
>>> If I were able to remember which tape id's are still in use, is there
>>> a way I can tell CppAD which id to use next?
>>>
>>> Best,
>>> Stefan
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>>> CppAD at list.coin-or.org
>>> http://list.coin-or.org/mailman/listinfo/cppad
>>>
>>
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>
>
>