How small residuals will lead to convergence?

[vincent53nhl]

Hi dear all,

How small should residuals be to reach convergence ?

My current situation is:
Residuals of the static equations:

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Equation number 1 : -0.81662
Equation number 2 : 0
Equation number 3 : 0
Equation number 4 : 0
Equation number 5 : 0
Equation number 6 : 0
Equation number 7 : 0
Equation number 8 : 0
Equation number 9 : 0
Equation number 10 : 0
Equation number 11 : -1.3604
Equation number 12 : 0
Equation number 13 : 0.0092545
Equation number 14 : 0
Equation number 15 : 0
Equation number 16 : 0
Equation number 17 : 0
Equation number 18 : 0
Equation number 19 : -0.16754
Equation number 20 : 0
%%%%%%%%%%%%%%%%%%%%%%%
STEADY: convergence problems

I have checked the initial conditons for equation 1 and 11, and both are correctly stated,
can you give some suggestions on how to achieve convergence ?

Note: it is a non-linear model, thus I also tried to change algorithms, but it did not work.

THANKS for all your help !

[jpfeifer]

Sorry, but either your model equations or your initial conditions are wrong. Please check them. There is no rule how small residuals must be to achieve convergence as this depends on the derivatives and the local minima.

[vincent53nhl]

Sorry, but either your model equations or your initial conditions are wrong. Please check them. There is no rule how small residuals must be to achieve convergence as this depends on the derivatives and the local minima.

Thank you for advise. But can I at least confirm there are no problems with the equations whose residuals equal to zero ??

[jpfeifer]

In general you can't unless there is some block recursiveness in the mode, which is usually not obvious. However, my experience is that you can focus on the equations where the residuals are not 0.