Ventana software support forum

Could Bob or anyone please help me to in resolving this issue? Any help is highly appreciated as I am stuck in linking Matlab and Vensim for more than a week.

Hi Bob Thanks for your suggestion. However, I installed both Model reader and DSS respectively on C drive, under 'Vensimfolder'. After that I modefied the path but it is showing the same problem like before. function loadModel(testlink) hfile=['C:\Vensimfloder\dll\Vendll.h']; loadlibrary('VenDLL32',...

Sorry, I just forgot the attachment

I am having moe or less same problem like ''ahmadi2010''.' I tried to open Vensim model from MATLAB by : function loadModel(testlink) hfile=['C:\Program Files\Vensim\Vensim\dll\Vendll.h']; loadlibrary('VenDLL32',hfile); str=('SPECIAL>loadModel|testlink.vpm') calllib('VenDLL32','vensim_command',str);...

Thanks Bob, for your unconditional support. I am very much surprised on the performance of FIND ZERO function. The above 3 equations are non-linear but not very complex. As per the advice of Tomfid, I thought that it would be an average catagory non linear equation solver like 'fsolve' of MATLAB. Bu...

Hi Bob Thanks for your response, especially at this curtail moment. Actually today is the last day for me to decide whether I will be using FIND ZERO function or not. I just stuck in following your instruction, may be due to the lack of knowledge in Vensim. I tried to solve a simple problem just to ...

I am eagerly waiting for your response, as I am fully stuck with my research at this point. It would be highly appreciated if any of you please show me a simple example of using FIND ZERO function. I couldn't get clear idea after looking at the Vensim Manual.

Thanks for your valuable suggestion. I am trying to solve a system of nonlinear equations for my reseach purpose. It has 26 variables and 33 parameter values and these parameter values are time dependent. It would be very helpful if you can please show me how to write a simple problem, so that I can...

Hi I need to call 'fsolve' function of MATLAB in my Vensim (Venext.c) file. Actually I am using external function facilities of Vensim to do some optimization. Previously I was working with IMSL library but it seems very difficult now a days. Therefore I like to use 'fsolve ' function in my Vensim m...

Hi Bob
I tried with your way, as well as followed the link that you mentioned. None of theme worked for me. I am attaching my file for your review.

Thanking you in advance

Khaled

[Edited on 6-22-2010 by khalediwm]

Thanks Bob, for your advice and I will try my best. Could you please let me know, how to write an external function, with such arrays, as I mentioned to you before that I am not clear about the values under "COSINE" function? I don't know how you choose those 0 and 1 ? If you have any exam...

another file

Hi I am trying to use, external functions of VENSIM to solve nonlinear series of equation, which consist of 26 variables and 33 constants. I used Visual Studio 2008 and IMSL library function to calculate the roots. The program works fine in Visual Studio environment. However, I am having problem whi...

Hi Tom
Thanks for your suggestion. I will try to implement it.

Hi Tom Thanks for your suggestion. However, I am still not clear, how can I get more than one variable from the external function, as the usual way of calling an external function is Y= Externalfunction (x1,x2,...xn). In case of having all the route, how should I modify my equation. In the conventio...

HI I am trying to work out an optimization problem, by solving systems of non-linear equations. I know that I have to use external function facilities. But I have 27 nonlinear equations to solve. So, I may have more than 27 optimized variables & parameters to return in Vensim ( in every time ste...

Lets say I need to calculate the rate of change for any variables, but I don't know how to store data from the previous time step (T-1)? Can anybody help me please?