Re: structures in oct files

[Andy Buckle]

On Fri, Jan 21, 2011 at 8:28 AM, jacques.beilin <address@hidden> wrote:
> Hi,
>
> I want to write a package based on oct files in order to manage GPS time
> (GPS week number, day of week, day of year, second of day, second of week,
> mjd...). I have already written such a package but it was based on m-files.
>
> In the package, I have several initialization functions. For example mjd_t
> takes a modified julian date as input and gives back a structure with all
> the date fields. I also wrote a add_s function. It takes a structure and a
> number of second to add. The function gives back the structure with the new
> date.
>
> I have a problem when I write yyyyddds_t2.oct function. It take year, day of
> year and second of day as arguments. I want to initialize first a structure
> for yyyy, january 1st and then add 86400 seconds per day plus the seconds of
> day.
>
>
> Here is the code :
>
> #include <octave/oct.h>
> #include <octave/ov-struct.h>
> #include <octave/parse.h>
>
>
> DEFUN_DLD (yyyyddds_t2, args, , "Struct demo.")
> {
>    int nargin = args.length ();
>    octave_value retval;
>    octave_map ymdhms0;
>    octave_value_list rr;
>
>    if (nargin <2)
>        print_usage ();
>    else
>    {
>        Octave_map tgps;
>        double yyyy = args(0).double_value();
>
>        // 2 or 4 digits year management
>        if (yyyy<80) {
>            yyyy=yyyy+2000;
>        } else if (yyyy<100) {
>            yyyy=yyyy+1900;
>        }
>
>        const double ddd = args(1).double_value(); // ddd : Day of year
>
>        double s = 0.0;
>        if (nargin==2) {
>            s=0.0000;
>        } else {
>            s = args(2).double_value(); // s : seconds of day
>        }
>
>
>        // calculating gpstime structure for yyyy, january, 1st,, 0h:00
>        std::string fcn = "ymdhms_t";
>        int nargout;
>        octave_value_list newargs;
>        newargs(0) = yyyy;
>        newargs(1) = 1;
>        newargs(2) = 1;
>        newargs(3) = 0;
>        newargs(4) = 0;
>        newargs(5) = 0;
>        rr = feval (fcn, newargs, nargout);
>        retval=rr(0);
>
>        // adding (ddd-1.0)*86400+s seconds to gpstime structure
>        std::string fcn2 = "add_s";
>        int nargout2;
>        octave_value_list newargs2;
>        newargs2(0) = retval;
>        newargs2(1) = s;
>        rr = feval (fcn2, newargs2, nargout2);
>        retval=rr(0);
>
>    }
>
>    return retval;
> }
>
> This code is successfully compiled but it crashes (octave terminal closed)
> on the line "  rr = feval (fcn2, newargs2, nargout2);". I suppose that the
> problem comes from retval which is an octave_value whereas add_s takes an
> octave_map for the first argument.
>
> I do not understand how (and when) to use octave_value and/or octave_map.
>
> Best regards,
>
> Jacques
>
>
>
> Le 20/01/2011 18:42, Andy Buckle a écrit :
>>
>> On Thu, Jan 20, 2011 at 3:25 PM, jacques.beilin<address@hidden>
>>  wrote:
>>>
>>> Hi,
>>>
>>> I do not know whether this question has already been sent to the list. In
>>> this case I am sorry to ask again.
>>>
>>> I would like to know if there is somewhere a tutorial and/or examples
>>> about
>>> oct files.
>>>
>>> I found  this :
>>>
>>> http://www.gnu.org/software/octave/doc/interpreter/Oct_002dFiles.html#Oct_002dFiles
>>>
>>> I wrote some sample programs but I have parameter problems when I try to
>>> call other oct files from an oct file. I try to send structures as input
>>> and
>>> output.
>>
>> When I have done similar, I have made a c++ function that actually
>> does the job I want. To make this available from Octave I have then
>> written a DEFUN_DLD that does extra parameter checking and then calls
>> the actual function. If I want to call the function from other c++,
>> then I call it directly. I pass by reference, to keep things quick.
>>
>> If you want more helpful comments, you may have to provide the list
>> with more details of your approach, and the problems you had.
>>
>
> --
> ___________________________________________
>
> Beilin Jacques
>
> Département Positionnement Terrestre et Spatial
> Ecole Nationale des Sciences Géographiques
> Institut Géographique National
>
> Cité Descartes
> 6,8 avenue Blaise Pascal - Champs Sur Marne
> 77455 Marne La Vallée Cedex
>
> tel : 01 64 15 31 09
>
> http://www.ensg.ign.fr/Positionnement-Terrestre-et-Spatial-geodesie
>
>
>

I don't have the time it would take me to look at this properly ATM. A
quick note that might help: octave_value has a constructor that can
take a map.

octave_value::octave_value      (       const Octave_map &       m       )      

Hopefully someone else on the list can provide a more expert comment.

-- 
/* andy buckle */