Ventana software support forum

geo_curious wrote: ↑Sat May 11, 2024 5:44 pm I did send the model on Friday by email to the Ventana info email address.

Thank you for sending the other email address. I will resend now.

I am using the latest version, yes.

An update - I did send the model on Friday by email to the Ventana info email address. I have been trying uniform and random normal sensitivity runs this morning and there is no change. Vensim does not return any differences for anything but the changed parameter. If I do it manually, it works fine....

There is no floating point error if I reduce the tariff by 10%, manually. I will send the model.

I have also tried creating a list of some selected parameters from the advanced tab. They all also returned floating point errors.

A uniform variation on a single parameter, which works fine with regular simulation runs, also does not work when attempting a basic sensitivity run.

From the S2A screen, I chose to simulate 1 param +/- 10%. Screenshot 2024-05-09 081454.png The result shows a series of failures. Screenshot 2024-05-09 081539.png I do not actually see anything different in return - I am not sure where the results of the simulation run go from selecting within the S...

Hi Tom, Your last explanation made sense. I am not showing the model because I have already had my previous work copied and claimed by many other people. In reflecting on this, I do not need the SUM() at all, since I can simply write in constants for this particular equation, which makes it all rela...

Hi,

I am running a Sensitivity2All. Each run I do is reflecting a floating point error in the S2A results. There does not appear to be any variable that I select that does not return a floating point error. The simulation will run fine, as is.

Does anyone have any advice on this for S2A?

I need to counter this by asking what the SUM() function is. It does not appear that it is a large operator, upper case sigma. If it was, it would not need subscripts at all. h does nothing. It is a formality in an attempt to get SUM() to work like a sum. In the manual and in the program I cannot si...

Hi, As usual, I have no idea where to find coherent documentation on subscripts in the Vensim manual. I am trying to use the SUM() function for the equation shown. Pretty straightforward in reality. In Vensim it is like pulling teeth. picture.png Shown is what I have input into the variable: picture...

The problem with the help file stating: "The remaining arguments must all be numbers." is that the variable inputs are numbers. Fine though Admin, I get it. Thank you.

Thank you for the answer. It seems you understood quite clearly what I was asking.

I am not sure that this is impossible to answer. I am not asking anything about my model. Rather, why are the different integration techniques not affecting behavior at the same time step? The signal is entirely the same, offering a control which indicates the only problems are the integration techn...

Hi, I recently switched my integration technique on an hourly simulation to RK2Auto. After looking more closely at the impacts on the model, I found significant errors. I understand that the RK methods are basically midpoint Euler steps, but I wonder why they are forcing a delay in integration withi...

It's not a big deal. I switched the function out because SINTEG is a bit unnecessary for what I need to accomplish. For the record, it does not appear that it will take anything but integers in place of min/max.

Hi all,

I am attempting to implement inputs for the SINTEG function. I am trying to assign the min and max values as min=(var1-(var1*.3)) and max=(var1+(var1*.3)). For some reason the SINTEG function does not like using variables as the input for min or max. Is there a workaround to this?

Thank you!

Thank worked, thank you!
Looks like...
SAMPLE IF TRUE( LMTD>max LMTD, LMTD, LMTD)

Hi all, I am running into this requirement on several simulations. I need to solve for another variable by using the MAX of another variable which may only be found through running of the simulation. VMAX and VMIN appear inappropriate for the case I will show here. I believe it seems appropriate for...

Spot on. This is perfect. Thank you for taking the time on this one.

If nothing else in this long discussion topic, I have become more familiar with subscripts in Vensim. I look forward to that enhancement!

I am trying to extract a constant, as in the above table. I do not see how I can explain this very, very simple effort any more clearly. 1. There is a lookup table. It contains inside diameters. 2. There is a pressure number that must be selected because it dictates how thick the pipe needs to be. 3...

This just does not make any sense. According to the example file for the VECTOR LOOKUP, the x, y, values are input to a standardized distribution range of x-min to x-max and y-min to y-max. I, however, input a value of x = 6 and y = 25 which should be "21" in the lookup, but I get 3. This ...

I found one problem in the model. The previously defined variables PN2 - PN16 had lookup tables that were throwing some errors. I deleted those variables and redeclared them as subscripts. Now the model runs. However, the output from lookup is erroneous and appears extrapolated? Not sure. How would ...

Hi JJ, The VECTOR LOOKUP makes sense, sort of. Unfortunately, it does not work either. I am going to layout my attempt at making the VECTOR LOOKUP function work. From the example "VECTOR_LOOKPU.mdl" above. XDim[x1, x2, x3], YDim[y1,y2,y3,y4,y5] 2-dim.png So I set my test problem up as ODDi...

Sorry to hear you are under the weather. I will try to explain this again. This is the order of operations: 1. Pressure number is selected 2. Pressure number limits the pipe diameters. 3. Outside pipe diameter is selected. 4. Based on the selected pressure number and the selected outside diameter th...

Here is the non-ideal workaround I came up with, not knowing how to do the two-dimensional lookup. I add X+Y=Z, then Z=index for lookup, then LOOKUP EXTRAPOLATE(lookup inside diameter, X+Y ). So the lookup appears as:

In this case, I think it would be sufficient to assume the tubulars I am working with will not change, but if adding complexity to future production changes this would be a problem. Ok, thank you for the responses.