[TRNSYS-users] simulation running unstable/stops, NaN in output?

[David Bradley]

Wouter,
  'NaN' stands for "not a number" and is what happens in most Fortran 
compilers when you divide a number by zero, when you take the log of a 
negative number, when you raise a negative number to a non-integer 
power, etc.. Usually once an NaN occurs, it will not fix itself but gets 
worse and worse because the result of every operation that you carry out 
with a variable that has been set to NaN is also NaN. The only reliable 
way to track down why it is happening is to run your simulation from the 
compiler and put a breakpoint into your code, then step through it one 
line at a time so that you can see where the NaN occurs first.
Kind regards,
 David


Wouter Lumen wrote:
> Dear TRNSYS-users,
>
> I have made my own component for modeling an ice-storage tank.
> I can run this component in a simple simulation with few other components, and
> it runs flawless. I have tested the component with a wide variety of  
> input values and parameters, and it always works fine.
>
> When I put this component in a more complicated simulation, I mostly  
> get "invalid floating point errors". Also if i put out some component  
> outputs through a printer in an excell-file, I get "NaN", sometimes a  
> whole column full, sometimes just one NaN in between the normal values.
>
> I have checked the input values for the component and non of them are  
> out of range. I also have checked that the component order is as it  
> should be.
>
> Does anybody know where this NaN comes from and what it means?
>
> Are there parameters that i can change in TRNSYS to make the  
> simulation run more stable?
>
> Thank you!
>
> Kind Regards,
>
> Wouter Lumen
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> TRNSYS-users at engr.wisc.edu
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>
>
>
>   

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