Re: Help with odeset()

[Rik]

On 10/16/2016 08:56 AM, Matteo Frigo wrote:

These are the outputs on r2016a:

x = odeset ('reltol', 1e-1)

x =

               AbsTol: []
                  BDF: []
               Events: []
          InitialStep: []
             Jacobian: []
            JConstant: []
             JPattern: []
                 Mass: []
         MassSingular: []
             MaxOrder: []
              MaxStep: []
          NonNegative: []
          NormControl: []
            OutputFcn: []
            OutputSel: []
               Refine: []
               RelTol: 0.1000
                Stats: []
           Vectorized: []
     MStateDependence: []
            MvPattern: []
         InitialSlope: []

___________________

y = odeset ('RelTal', 1e-2)
Error using odeset (line 225)
Unrecognized property name 'RelTal'.

__________________

z = odeset ('Rel', 1e-3)

z =

               AbsTol: []
                  BDF: []
               Events: []
          InitialStep: []
             Jacobian: []
            JConstant: []
             JPattern: []
                 Mass: []

         MassSingular: []
             MaxOrder: []
              MaxStep: []
          NonNegative: []
          NormControl: []
            OutputFcn: []
            OutputSel: []
               Refine: []
               RelTol: 1.0000e-03
                Stats: []
           Vectorized: []
     MStateDependence: []
            MvPattern: []
         InitialSlope: []

_______________________

w = odeset ('MyCustomProperty', 1)
Error using odeset (line 225)
Unrecognized property name 'MyCustomProperty'.

Thanks Matteo and Parsiad for testing this code.

I filed a bug report about Octave  not implementing non-exact match to property names (https://savannah.gnu.org/bugs/index.php?49364).   Quoting from that report,

---- Quote ---

In Matlab, odeset will match a partial property name to the exact property name. Octave does not do this. Instead, it creates a new property under the abbreviated name.

This is a problem. Code on Matlab which makes use of this feature does not generate any warning, therefore, there is no indication that the option should be written more specifically. When this code is ported to Octave, it will run, but different results will be obtained because some options have not been set identically. As an example,

will set RelTol to a very strict 1e-12 in Matlab, but leave it at the default value in Octave.

--- End Quote ---

--Rik