Ventana software support forum

Hi

I am currently working with the 32 bits Vensim DSS version and think about migrating to the 64 one with the minimum of problems. What are the current problems encountered when migrating? I did not find any information about that in the Vensim documentation. Is it running at the same speed and if not at least not too slowly. What has to be changed when compiling? Can one keep the same compiler? Can one keep the same code or are there some modifications to be made? I have waited one year to migrate because I hate problems of migration and prefer to wait a bit so that the main problems get solved. I hope that it is the case. i migrate because i am tired of using the list of variables to be saved or increasing the saving time step.
The possibility to use sub models is too very interesting if it works!

Best regards.

JJ

I use the 32 and 64 versions interchangeably on the same machine without really noticing a difference, so you should have no trouble.

You can keep your compiler. The 64 version just uses a different variant of the mdl.bat. The only thing you might need to change is migrating any customized setting to the 64 bat file, though with a standard installation of Visual Studio, it works with no customization.

If you have external functions, they do need to be recompiled to 64 bit dlls.

There's no noticeable speed penalty.

If you have feedback on the submodels, we're eager to hear it.

Hi Tom

Thank you for the information. I will download the 64 version. if anything goes wrong i will inform you.

Best regards.

JJ

Hi

i have downloaded the 64 version. But the compiling does not work. I have still the older mdl.bat. Where is the 64 bits mdl;bat situated?

Regards.

JJ

Default location is c:\users\public\vensim\comp

Hi

i suppose taht the right file is named MDLDP64.bat. It calls files that i have not. I used an old visual compiler not the 2019 one. I will down load it and see if it works.

During installation, the default is to leave the comp folder intact. So you might need to reinstall but tick the box to install compilation files.

I'll change this for the next release as the old comp files should never be needed again.

Hi
i join the old mdl.bat that called a C compiler version 10. i do not wher to download the latest 2019 version. On the Microsoft site there is a visual studio 2019, but it is not free, more than 300 dollars. But if I use the old mdl.bat the compiler saus that it does not find the paths.

Regards.

JJ

I do not know which bar file to use: the old mdl;bat or the new one mdldp64.bat or maybe with changes. They are both in the right place users/public/vensim/comp

JJ

You can select either BAT file. What you are actually doing is selecting the path to the file, internally Vensim will call the correct one to compile the model.

It is still not working.

there is a message :

Compiling Vensim model …
Setting paths for Vensim compilation using Microsoft compilers
Visual Studio 10
The specified configuration file is missing. The tools
for the configuration might not be installed.
Creating optimized DLL.
‘CL’ n’est pas reconnu en tant que commande interne
Ou externe, ou programme exécutable ou un fichier de commandes.
Translation : ‘CL’ is not recognized as an internal or external command, nor an executable program or a command file.
Unable to compile – failed to set paths. Check the paths in mdldp.bat in vensim\comp
Appuyer sur une touche pour continuer …
Translation : press on something to continue

The mdl.bat is the old mdl.bat joined and there is an mdldp64.bat too in the \comp.

regards.

JJ

The Visual Studio 2019 community edition is free, unless the "enterprise" criteria trips you up. https://visualstudio.microsoft.com/lice ... mlt031819/

I'm not sure if v10 will work with x64 compilation, but the vcvars path may differ. Compare
to what is in the mdl64.bat.

What you are actually doing is selecting the path to the file,

... path to the directory really.

Hi Tom

I downloaded the 2019 version with the 'ticks'. The compilation works fine and the time to save up to 2 GO was OK. But it took more than an hour to save a 4.5 GO file! Is it normal?

Regards.

JJ

LAUJJL wrote: ↑Sun Jul 05, 2020 11:59 pmI downloaded the 2019 version with the 'ticks'. The compilation works fine and the time to save up to 2 GO was OK. But it took more than an hour to save a 4.5 GO file! Is it normal?

It could be normal depending on what hardware you are using. If you want us to test here, feel free to email the model to us.

Hi

I join the model. If you run it as it is it takes less than a minute to save. But it you change the value of the constant 'niveau de la demande totale par jour' in the first view 'programmation dynamique' from 8 to 16 it takes one hour and a half.

Regards.

JJ

Hi

Sorry the first view where the constant has to be changed has the name 'paramètres de base'

JJ

Hi

Sorry the first view where the constant has to be changed has the name 'paramètres de base'

JJ

I tried this experiment. Time step changes when you set "niveau de la demande totale par jour" meaning the results file is twice the size of the original. So it will definitely take longer to save. Mine still saved pretty quickly though for a 4.5gb file (but I am running a solid state drive).

What kind of hard drive are you running?

Hi

I talked to my technician. He says that changing to a solid state drive will may be increase the speed by say 30% but will not have a significant effect.
When i run with a parameter value of 8, and a file size of about 2.25 it takes 30 seconds and with the value of a parameter of 16 and a file size of 4.5 it takes one hour and a half. Which means that changing the drive will may be able to run in an hour but not much. How much time does it take with your solid state drive to run with both parameter values? My technician will have a look at my computer and how it runs today. I will report the experience to you.

Regards.

JJ

Solid state drives give a huge boost in performance, it's much more than 30%.

The model saves on my machine in less than a minute.

Hi

Thank you for the information. i know now that it is a hardware problem. I see my technician to morrow. I will get you informed.

Regards.

JJ

A quick search on Google will give you other opinions.

https://www.laptopmag.com/articles/help ... get-laptop
(When we ran our LAPTOP File Transfer Test, which involves copying 4.97GB of files, the hard drive operated at a rate of 33.9 megabytes per second while the SSD hit 237.8 MBps, which is about seven times as fast.)

https://www.pcworld.com/article/2048120 ... gains.html

HI

I finally found the reason. It is not because of the drive that I changed to a SSD, but because of the RAM that was only 4 gigabytes. I changed to a 12 gigabytes and it saved in 40 seconds instead of one hour and a half. In fact it is necessary to have a RAM that is at least bigger and probably a portion bigger than the size the .vdf file to be saved.

Regards.

JJ

Yes, definitely. The extra RAM would mean that results are stored in memory rather than a swapfile on the disk which is much slower.