[Scilab-Dev] Scilab Improvement Proposal

[Sabine GAUZERE]

Hello,

If I understood well the functioning of dassl with regard to ode, it may
be possible to extract easily xj,tj and xdj because dassl return a
vector containing the three arguments. According to serge it would not
be very sensible.
So what we do for the SIP and the function dae ? Do we keep the output
arguments such as they are? Do we stay on the idea to write a function
daeoptions() on the model of odeoptions() which would contain the
argument info?

Regards

Sabine


Le mercredi 25 juin 2008 à 14:30 +0200, Serge Steer a écrit :
> Claude Gomez a écrit :
> >
> > It would be good that the output of dae "y" has the same semantics as
> > ode's ie a matrix n X T where T is the size of t and each column j of
> > y is the value of y at time t(j).
> >
> > Claude
> >
> 
> Currently with dassl "y" is a  (1+2*n) X T matrix each column icontains
> [tj;xj;xdj].
> 
> For basic use tj values are redundant because they are a copy of the t
> input argument, but if info(2) ==1 the  time value associated to xj  is
> no more known ( intermediate computed values ). In ode "y" is a  n X T
> matrix each column  contains [xj] only if odeoptions(1)<>1 and [tj;xj]
> if odeoptions(1)==2. The dassl interface choice seems better for me, but
> it is not possible today to change the ode semantics. So may be we have
> to make dae behave as ode depending on info(2)
> 
> Moreover the xdj values cannot be recomputed easily given tj and xj. So
> i do not think it is a good idea not to return the xdj values.
> 
> Serge
> 
>