Re: Creating .oct files

[A Scottedward Hodel]

Another (more complex) example of .oct file implementation is

in my port of Boyd's semidefinite programming package

sp to octave; ftp://ftp.eng.auburn.edu/pub/hodel/semidef-oct.tar.gz

This includes interface functions that help to extract the

octave structure arguments into C++ objects (vectors, matrices).

I've used these interface functions repeatedly in several .oct

files I've written for my work in the last few months.

regards,

ash

At 8:52 AM +0100 4/19/00, Peter Gawthrop wrote:

Hi,

I am developing a set of system modelling tools which
ultimately generate .m files. (more info is at
http://www.mech.gla.ac.uk/~peterg/software/MTT/).

To speed things up, I now generate .oct files based on the
"Dynamically Linked Functions" section of the octave manual. As I know
nothing about c++ I used the "oregonator.cc" example as a
template. This all works fine.

At the moment (for example) I generate:
   rcPPP_cseo.oct
   rcPPP_cse.oct
   rcPPP_smxa.oct
   rcPPP_smxax.oct

and call them from the .m file given here.


function [y,x] = rcPPP_sim(x0,u,t,par);
% [y,x] = rcPPP_sim(x0,u,t,par);
%System rcPPP, representation sim, language m;
%File rcPPP_sim.m;
%Generated by MTT on Tue Apr 18 18:30:34 BST 2000;
%

  ## Initialise
  ui  = zero_input(2);      # Zero the input
  xi = x0;              # Read in initial state


  yi = rcPPP_cseo(xi,ui,t(1),par);    # First output

  ##Sizes
  N = length(t);

  ## Initialise  arrays  
  x = zeros(1,N);
  y = zeros(1,N);
  y(:,1) = yi(:);
  A = zeros(1,1);
  Ax = zeros(1,1);
  dx = zeros(1,1);

  ## Step size
  dt = t(2)-t(1);

  for i = 1:N
    ti = t(i);
    ui = u(:,i);
    y(:,i) = yi;
    x(:,i) = xi;
    dxi = rcPPP_cse(xi,ui,ti,par); # State derivative
    A = rcPPP_smxa(xi,ui,dt,par);   # (I-Adt)
    A = reshape(A,1,1);
    Ax = rcPPP_smxax(xi,ui,dt,par);     # (I-Adt)x
    xi = A\(Ax + dxi*dt);        # Implicit update
    yi = rcPPP_cseo(xi,ui,ti,par);    # Output
  endfor;                    

endfunction

To make things even faster, I would like to turn this rcPPP_sim.m file
into a .oct file. This is more complicated than the  "oregonator.cc"
example as:

1. It calls user defined .oct functions
2. It calsl the octave function  reshape
3. It uses the octave "\" operator.

I would be really gratefull if an octave expert could convert this
function into a .cc file for me to show me how to do it.

    Thanks,

Peter.

PS If anyone has an interest in the MTT modeling tools, please let me
know. I hope to distibute freely at some point in time.

--
=============================================================
Peter J. Gawthrop,
Centre for Systems & Control
          and
Department of Mechanical Engineering

Room number: James Watt 603
             (Third floor opposite the seminar room)
WWW:
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E-mail:
  address@hidden

Address:
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  University of Glasgow,
  GLASGOW. G12 8QQ
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--
A S Hodel Assoc. Prof. Dept Elect and Computer Eng, Auburn Univ,AL 36849-5201
On leave at NASA Marshall Space Flight Center (256) 544-1426
Address until 31 July 2000:Mail Code TD-55, MSFC, Alabama, 35812
http://www.eng.auburn.edu/~scotte