Not enough memory in Vensim

[luisangelguzmang]

Hi, I was trying to simulate my model in Vensim, but I couldn't. My model have 124 x 124 matrix and 4 subindex (as maximum), time step=1 and time between 0 to 30. After final time=30, the error message is: "Not enough memory - decrease lenght or increase SAVEPER".

error1.jpg (12.28 KiB) Viewed 11834 times

Then I try again with final time=20, and then appear "insufficient memoty to allocate handle for 243175640 bytes". Or the software held in the window time=20 forever and says "not response".....

error2.jpg (12.95 KiB) Viewed 11834 times

error3.jpg (160.69 KiB) Viewed 11834 times

So, how can fix this? Thks!!

[Administrator]

Can you upload the model so we can take a look?

I suspect you are going to have to reduce the 124x124 matrix as this is going to use up a lot of memory.

[luisangelguzmang]

Sorry, this is the model...

[Administrator]

What are i and j in your model?

[luisangelguzmang]

there are zones. In my model there are a 124 zones, so i are the origin zones, and j are the destination zones, for estimate the trips between them, for example.

[Administrator]

Can you combine the zones at all? What I mean is, do all zones go to all other zones? Can you create a smaller array with just the from and to zones?

This will be the easiest way of making the memory requirements of the model much smaller.

[luisangelguzmang]

Ok, but is the only way? Reduce de number of subindex?

[Administrator]

If you are hitting memory limits, yes, you will need to re-work the model so that you can reduce the number of subscript elements.

Just replace i and j with a single subscript range called "route". Then only have the routes that will actually be used (eg, "London to Paris", "London to Rome" etc). This of course will only work if you can cut down the routes from all to all.

Tony.

[luisangelguzmang]

Ok, thank you Tony. So, it is impossible to expand the memory?

[Administrator]

It is impossible for now as Vensim is a 32 bit application (limited to 2gb total RAM).

[tomfid]

Typically a model that pushes memory limits will execute extremely slowly anyway.

Just how big is this one (as indicated by Model>Settings>Info)?

[luisangelguzmang]

Well, i would not mind that model executes slowly. The model info is the following:

Model info

Info.jpg (36.93 KiB) Viewed 11786 times

[tomfid]

Right. This is probably going to take about 120MB per step. It might run with a long SAVE PER, but that'll make it hard to debug. Sorry.