Use VDFX file

[LSarribouette]

Hi all!

We are building an app with SDEverywhere and we don't succeed to use a model that has calls to a VDFX file through the GET VDF DATA function.

Would you have some insights to make it work?

We tried following this answer: #480 (reply in thread)

Here a mini-model we are using for testing purposes (which runs properly in Vensim):

{UTF-8}
Country:
	World, Africa,China,DevelopedAsia,DevelopingAsia,Eurasia,Europe,India,Latinamerica,Middleeast\
		,NorthAmerica,France
	~	
	~	
	|

CountryRegionWorld:
	Africa,China,DevelopedAsia,DevelopingAsia,Eurasia,Europe,India,Latinamerica,Middleeast\
		,NorthAmerica,France
	~	
	~		|

EJinXXX=
	1.70619e+08
	~	
	~	
	|

GDPPerCapitaObs[Country]:INTERPOLATE::=
	GET VDF DATA( 'Get.vdfx' , 'GDPPerCapitaObs[country]' ,0, 1)
	~	
	~		|

PopObsTab[Country]:RAW::=
	GET VDF DATA( 'Get.vdfx' , 'PopObsTab[country]' ,0, 1)
	~	
	~		|

In the initial folder, we place the MDL file, the corresponding DAT file (exported in Vensim from the Get.vdfx) and a config/model.csv file as follows:

graph default min time,graph default max time,model dat files
1980,2100,Get.dat

After running npm create @sdeverywhere, it compiles properly and creates the project structure without error.

After running npm run dev, we get the following error:

> project@1.0.0 dev
> sde dev

Generating files...
Done generating files (0.0s)
Generating model...
  Error: Unhandled function '_GET_VDF_DATA' in readEquations for 'GDPPerCapitaObs[Country]'

[chrispcampbell]

Hi @LSarribouette, a key detail in my comment in #480 (see first bullet item) is that SDEverywhere does not currently support the GET VDF DATA function, which is why you are seeing that error.

In a Vensim .mdl, to use data from a .vdfx file, in many (most?) cases you don't need to use the GET VDF DATA function. As long as your .vdfx file is referenced in your Vensim model settings, then you refer to data variables (from the .vdfx file) in a model equation like this:

x[country] = some data variable in vdfx[country] ~~|

If you can make your model work correctly in Vensim using that kind of syntax, then you should be able to use the same model with SDEverywhere using the approaches I described in #480. Let me know if you're able to figure it out or if you need any more guidance.

One thing to note is that (unfortunately) SDEverywhere currently ignores the :INTERPOLATE: and :RAW: keywords (it does interpolation by default). If you need control over those behaviors, there may be workarounds depending on the use case. Or feel free to file an feature request in a new GitHub issue.

[LSarribouette]

Hi @chrispcampbell , thank you for your reply!

Indeed, I hadn't understood that we had to remove all calls for GET VDF DATA...

We will work on that and hopefully get it to work properly!

[LSarribouette]

Hi @chrispcampbell , thank you for your reply!

Indeed, I hadn't understood that we had to remove all calls for GET VDF DATA...

We will work on that and hopefully get it to work properly!