vensim_get_varnames returning negative, license renewal issue

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diginthedust
Junior Member
Posts: 3
Joined: Mon Aug 20, 2018 1:07 am
Vensim version: DSS

vensim_get_varnames returning negative, license renewal issue

Post by diginthedust »

I'm using Vensim DSS for Windows 7.2.

Recently, I’ve been running into errors when I try accessing the dll using the Python wrapper VenPy (https://github.com/pbreach/venpy). When I try loading a model using venpy.load() I get a message: “This limited time copy has expired”. This is related to the Vensim license which did expire recently but when I renew and reinstall (using admin privileges) the problem persists. Apparently this is a common issue that may not be resolved yet according to the below forum topic.
viewtopic.php?t=6935

Here's the python error trace ending with self.dll.vensim_get_varnames() returning a negative number. Anybody have any thoughts? Help would be greatly appreciated.

Code: Select all

ValueError                                Traceback (most recent call last)
<ipython-input-2-33805c1d6dfa> in <module>()
----> 1 model=venpy.load("simple.vpm")

~\Documents\VenPy\venpy-master\venpy\venpy.py in load(model, dll)
     29     VenPy model object
     30     """
---> 31     return VenPy(model, dll)
     32 
     33 

~\Documents\VenPy\venpy-master\venpy\venpy.py in __init__(self, model, dll)
     76         for num, var in types.items():
     77             maxn = self.dll.vensim_get_varnames(b'*', num, None, 0)
---> 78             names = (ctypes.c_char * maxn)()
     79             self.dll.vensim_get_varnames(b'*', num, names, maxn)
     80             names = _c_char_to_list(names)

ValueError: Array length must be >= 0, not -6
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Re: vensim_get_varnames returning negative, license renewal issue

Post by Administrator »

Please email us regarding this (and don't forget to quote your licence details).
Advice to posters seeking help (it really helps us to help you)
http://www.ventanasystems.co.uk/forum/v ... f=2&t=4391

Units are important!
http://www.bbc.co.uk/news/magazine-27509559
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