[Developers] return_arrays_increment();

[John Sibert]

Hi Mark -

A couple of comments on libraries and FUNCTIONS.

I'm not sure what you mean by libraries. A library is simply a file 
containing a bunch of object files. Make in library in linux is trivial 
using ar, and under windows, most compilers provide a tool to assemble 
object files into a library. The header files must also be provided, of 
course, and I would encourage (or perhaps even require) people who want 
to contribute libraries to document the API using doxygen.

I'm also confused about the lack of RETURN_ARRAYS_INCREMENT(); and 
RETURN_ARRAYS_DECREMENT(); statements in the FUNCTION examples (and 
indeed in many FUNCTIONs that I have written.) It appears that you can 
get away without them in some applications, but most definitely not in 
others.

Cheers,
John

Mark Maunder wrote:
> I am thinking about putting an article on functions and one on making
> libraries in the next ADMB Newsletter. Along with this I want to get a
> couple of libraries from existing users to put on the website as a start
> to a user created repository of libraries (these would be for use at
> your own risk and not official ADMB code). (let me know if you have a
> library you would like to contribute) I already have text from Steve
> Martell on creating libraries, but I think something on writing
> FUNCTIONs in ADMB would be a good companion. If anyone is interested in
> writing this let me know. In the mean time, where is all the information
> on writing functions in ADMB. The manual uses them a lot including
> functions that accept and return variables e.g.
>
> FUNCTION dvariable h(const dvariable& z)
> dvariable tmp;
> tmp=exp(-.5*z*z + tau*(-1.+exp(-nu*pow(a(a_index),beta)*exp(sigma*z)))
> );
> return tmp;
>
> The examples don't use the RETURN_ARRAYS_DECREMENT(); commands. Users
> also need to know about deep and shallow copies, overloading, ....
> (which are probably all C++ commands, but most ADMB users aren't C++
> programmers).
>
> Thanks,
>
> Mark
>
>
>
> -----Original Message-----
> From: developers-bounces at admb-project.org
> [mailto:developers-bounces at admb-project.org] On Behalf Of dave fournier
> Sent: Tuesday, September 15, 2009 10:04 AM
> To: Arni Magnusson
> Cc: developers at admb-project.org
> Subject: Re: [Developers] return_arrays_increment();
>
> Arni Magnusson wrote:
>
> Well it is not just a matter of sticking a
>
>   RETURN_ARRAYS_DECREMENT();
>
> at the end of the function because there may be a complicated set of
> returns in the function.
> Interesting that you think of this as low level housekeeping, but R
> users are happy to  calculate the derivatives by hand
> which strikes me as low level, boring, and error prone.
>
> However the entire return arrays construction is probably not needed any
> more.  Compiler optimization may have made it redundant
> and even inefficient. You should keep in mind that the code was designed
> to run on the first Borland Turbo C++ compiler with 640K under DOS
> in 1990.
>
> There are a number of areas where it really shows its age.
>
>   
>> Modellers would be very grateful if they wouldn't have to do this kind
>> of low-level housekeeping. Do you think it would be feasible to make
>> tpl2cpp insert
>>
>>   RETURN_ARRAYS_INCREMENT();
>>
>> and
>>
>>   RETURN_ARRAYS_DECREMENT();
>>
>> automatically into the C++ source code, if the return value is of
>> dvariable type? This would make ADMB code clearer and much more robust
>> to user mistakes.
>>
>> In terms of backward compatibility, does anyone know if it would be
>> okay to repeat the "protective braces" like this,
>>
>>   RETURN_ARRAYS_INCREMENT();
>>   RETURN_ARRAYS_INCREMENT();
>>   // code
>>   RETURN_ARRAYS_DECREMENT();
>>   RETURN_ARRAYS_DECREMENT();
>>
>> in case the user has also included them in the TPL?
>>
>> Arni
>>
>>
>>
>> On Fri, 4 Sep 2009, Richard Methot wrote:
>>
>>     
>>> There is no mention of this return_arrays queue issue in the ADMB
>>> manual. Is there any reason for this being specific to AUTODIF?
>>>
>>> Rick
>>>
>>>
>>>
>>> John Sibert wrote:
>>>
>>>       
>>>> Dave provides the "bullet proof" solution. Look near page 3-7 in the
>>>> AUTODIF manual.
>>>>
>>>> John
>>>>
>>>>
>>>>
>>>> dave fournier wrote:
>>>>
>>>>         
>>>>> In this case you can get rid of the error in this way but as I
>>>>> already said in general you should read about
>>>>>
>>>>>    return_arrays_increment();
>>>>>    return_arrays_decrement();
>>>>>
>>>>> if you have functions that return a dvariable object.
>>>>>           
>> _______________________________________________
>> Developers mailing list
>> Developers at admb-project.org
>> http://lists.admb-project.org/mailman/listinfo/developers
>>
>>     
>
>
>   

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