[TRNSYS-users] numerical solution in new type with C++

[David BRADLEY]

Iris,
  I am no expert in writing C++ components (in fact I have never tried 
it). My guess, however, is that you will need to modify the TRNSYS.h 
file to make sure that the setNumericalDerivative() and 
getNumericalSolution() functions are actually defined in there.
Kind regards,
  David


On 8/27/2014 07:52, Iris Reichenbach wrote:
> Dear fellow TRNSYS users,
> I have the following problem. I'm trying to write a new type for 
> TRNSYS in C++, which involves the numerical solution of differential 
> equations. Usually, SetNumericalDerivative is used to set the 
> numerical derivatives and then GetNumericalSolution is used to obtain 
> the solution of the differential equation. However, when trying to 
> compile my code the compiler gives the following error: "error C3861:  
> "getNumericalSolution": Bezeichner wurde nicht gefunden." That is, it 
> can't find the identifier getNumericalSolution.
> I also tried to instead use the older form and write dtdt[i] = x, 
> instead of SetNumericalDerivative(i,x), but here I got the error 
> message "error C2109: Index erfordert ein Array oder einen Zeigertyp" 
> (that is index requires an array or a pointer).
> I  use the project CPP-Mvs2003, which is included in TRNSYS/Compilers, 
> so it has access to TRNSYS.h and TRNDll.lib, and I also successfully 
> used my setup to generate another custom type, albeit without any 
> numerical solution.
> So my question is: how can I solve numerical equations with a type 
> written in C++? How do I set the derivatives and how do I access the 
> solutions? Do GetNumericalSolution/SetNumericalDerivative not work 
> with C++ (I didn't find them in TRNSYS.h) and if so, what do I use 
> instead?
> Thanks in advance for any pointers!
> Cheers,
> Iris
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>

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David BRADLEY
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