Ventana software support forum

Hi,
Thnaks for the remark. I have solved the problem.

Hi, I am developing a land-use change model in Vensim. The problem is that I have land-use conversions with different time delays and so when I estimate the share of each land-conversion type I get a peak resulting form the different time delays that is not consistent. I need to estimate the share o...

Hi,
I need to export vensim model structures as figures to be inserted in a repport. Do you know how to do this? I have try to save as tiff but images are in monochrome.
Thanks

right. Thats what I'm trying to model. The expectation on harvest is thought based on the planted area decision, that in turns depends on the expected price at the harvesting time. So, I think I am not understanding the difference betwen what you say and what the model does. Please can you comment o...

Hi, Thanks for the units correction. Now the domensional errors are correct, but however, I need to reduce oscilation to a year to year basis. Normaly soybean stock should oscilate from year to year, as soybean stock is reduced throught out the year due to soy consumption, until the next harvest is ...

Hi, I have developed a simple model of soybean supply/demand dynamics. The model purpose is to model price and supply response to an exogenous demand. Teoretically they should match the reference modes, but its not the case. I have mainly three problems: 1. Stock oscilations should be annual and not...

Hi Tom,
Thanks. Its true. I think is was a problem of calibration, as I have managed to get now a rational behavour.
thanks

Hi, I want to define a point to initialize a simple model of cropland dynamics. I am getting an overflow error now because i think its being initialize in the wrong place. I should have a first shock on crop demand that increses managed land increasing land value and then driving intensification. Ho...

thanks !!! that works !

Hi, I am having 2 errors when trying to simulate a national land-use change model. Each land-use type is a sock that varies in fucntion of changes in other land-use types stocks. I get that some model variables (stocks) are not used. However, I only want to see how this stock evolve over time and no...

Hi, Thanks for the correction. Actually, I have tried to reproduce Meadows commodity cycle, where prices are auxiliary variables and there is a feedback loop on consumption-inventory coverage and prices. But I dont know why I get this simultaneous equiation error and Meadows dont. Can I solve this p...

Hi,
I have a problem in my model. When trying to simulate the model I get an error of simultaneous equations and I cant solve it !!
I have check vensium documentation in this error but I cant solve it !
I post the model. Can somebody take a look please?
Thanks !!!

Hi,
Yes, you have to correct the error.
Change all priorities in the attractiveness functions by numbers: e.g.

attractiveness[Corn,pprofile]= 3,corn priority,0,0 ~~|

change corn priority by 1, etc, etc

attractiveness[Corn,pprofile]= 3,1,0,0 ~~|

great tom ! that works ! thank you very much !!!

Hi,
I am a PhD student at the Swiss Federal Institue of Technology and I am developing a SD model for my thesis to study land-use changes is soybean-based biodiesel production in Argentina.

ok, so, as much as I see I cant use "allocate available" with variables. I will try developing a market share structure based on relative attractiveness, because I need demand and attractiveness to chage over time.

Hi Bob and Tomfib ! Bob: I have tried with ALLOCATE AVAILABLE but I applied it to the whole “managed land” because I did not knew how to allocated land between the other land uses then. I have defined an aggregated stock of "managed land" where land shares of the “managed land expansion ra...

Hi bob, I have an allocation problem that I am trying to solve using the "allocate available" function. However, after reading the manuals I can't really understand how it works and implement it. This is my problem: I have to allocate "total available suitable land" between diffe...

thanks bob !! it works

Hi,
I hold a DSS version of Vensim, but I cant find the "allocation by priority" function. Normally, it should be included in this version.
Can we imported it? or can you tell me why I do not have it in my version?