[Octave-bug-tracker] [bug #49871] ode15s, MStateDependence option incorrect

[Bill Greene]

URL:
  <http://savannah.gnu.org/bugs/?49871>

                 Summary: ode15s, MStateDependence option incorrect
                 Project: GNU Octave
            Submitted by: billgreene
            Submitted on: Sat 17 Dec 2016 06:58:17 PM GMT
                Category: Octave Function
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: dev
        Operating System: Any

    _______________________________________________________

Details:

I have just started doing some testing of the new ode15s function.

I have discovered incorrect behavior when the Jacobian option is
specified. I get the following warning message:

warning: with MStateDependence != 'none' an internal approximation of Jacobian
Matrix will be used. Set MStateDependence equal to 'none' if you want  to
provide a constant or time-dependent Jacobian
warning: called from
    ode15s at line 258 column 7
    test_ode15s_jac at line 23 column 13

I believe that ode15s.m is, for some reason, using the setting of
MStateDependence  to ignore my Jacobian function. This is the
wrong interpretation of MStateDependence. My understanding is
that MStateDependence in MATLAB just serves as a "hint" to the code that it
may be able to adjust the algorithm slightly to improve performance. 

I am attaching a small script that reproduces this behavior.





    _______________________________________________________

File Attachments:


-------------------------------------------------------
Date: Sat 17 Dec 2016 06:58:17 PM GMT  Name: test_ode15s_jac.m  Size: 1kB  
By: billgreene

<http://savannah.gnu.org/bugs/download.php?file_id=39260>

    _______________________________________________________

Reply to this item at:

  <http://savannah.gnu.org/bugs/?49871>

_______________________________________________
  Message sent via/by Savannah
  http://savannah.gnu.org/