Re: structures in oct files

[jacques.beilin]

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