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## Re: DAE daspk solver problem

 From: Lazy_Tom Subject: Re: DAE daspk solver problem Date: Sat, 29 Oct 2016 10:57:50 -0700 (PDT)

```Sebastian Schöps wrote
>
> Lazy_Tom wrote
>> the output was :
>>
>> warning: Option "RelTol" not set, new value 1.0e-006 is used
>> warning: called from
>>     radau5_test_1_V04 at line 19 column 6
>> warning: Option "AbsTol" not set, new value 1.0e-006 is used
>> warning: Option "NormControl" will be ignored by this solver
>> warning: Option "InitialStep" not set, new value 1.0e-006 is used
>> warning: Option "MaxStep" not set, new value 1.4e+000 is used
>> warning: Option "Mass" only supports constant mass matrices M() and not
>> M(t,y)
> Did you see the last line? The solver does not like function handles for
> the mass matrix. However, you can just use the matrix itself:
>
> vmass =  diag([1, 1, 1, 1, 0]);
> vopt = odeset ('Mass', vmass, 'NormControl', 'on');
>
> I will try to look to your example in more detail next week.
>
> Sebastian

The reasono why I didn't use the matrix and opted for the ready-made example
is that the matrix didnt work.
In any case, I send you the code and the error, hope it helps

function [vyd] = frobertson (vt, vy, varargin)
vyd(1,1) =  vy(2);
vyd(2,1) =  -vy(1) * vy(5);
vyd(3,1) =  vy(4);
vyd(4,1) =  -vy(3) * vy(5) - 10;
vyd(5,1) =  vy(1)^2 + vy(3)^2 - 1;
endfunction

vmass =  diag([1, 1, 1, 1, 0]);

vopt = odeset ('Mass', vmass, 'NormControl', 'on');
vsol = ode5r (@frobertson, [0, 17], [1, 0, 0, 0, 0], vopt);
plot (vsol.x, vsol.y);

output:

warning: Option "RelTol" not set, new value 1.0e-006 is used
warning: called from
radau5_test_1_V05 at line 18 column 6
warning: Option "AbsTol" not set, new value 1.0e-006 is used
warning: Option "NormControl" will be ignored by this solver
warning: Option "InitialStep" not set, new value 1.0e-006 is used
warning: Option "MaxStep" not set, new value 1.4e+000 is used
warning: Option "NewtonTol" not set, default value is used
warning: Option "MaxNewtonIterations" not set, default value 7 is used
EXIT OF RADAU5 AT X=        0.2428E-02
STEP SIZE T0O SMALL, H=   2.1389523049476520E-018
error: missing implementation
error: called from radau5_test_1_V05 at line 18 column 6

Marco

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```