•Vensim 10.3 comes with a completely redesigned equation editor; see the Reference Guide section ‘Equation Editor’ for more information. Instructions on how to revert to the legacy equation editor are also here.
•Data variables are now available when publishing a model to the web.
•New graph color palettes that respect color vision deficiency. To access these, click Tools->Options->Graphs, you can quickly access different palettes. We have also changed the default palette that Vensim uses to be one that should be easier on users with a color vision deficiency.
•Export of multiple datasets at the same time is now possible.
•New option for custom graphs to only truncate the x axis to start/end when data is visible.
•Some new SIMULATION special variables reserve names for MCMC output to be ignored in sensitivity runs.
•A new checkbox in the sensitivity setup permits variation of the NOISE SEED without having to add a VECTOR distribution to do this. Use case: varying a random process in the model, so that you can combine the parameter uncertainty in an MCMC sample with aleatoric uncertainty in some kind of sampling process (e.g., covid testing).
Pro & DSS
MCMC
•Algorithm update to DREAM-ZS for better acceptance and faster convergence.
oJ.A. Vrugt (2016), Markov chain Monte Carlo simulation using the DREAM software package: Theory, concepts, and MATLAB Implementation, Environmental Modeling & Software, 75, 273–316, doi:10.1016/j.envsoft.2015.08.013.
oC.J.F. ter Braak, and J.A. Vrugt (2008), Differential evolution Markov chain with snooker updater and fewer chains, Statistics and Computing, 18(4), 435-446, doi:10.1007/s11222-008-9104-9.
•Initialization step is now parallel (big speedup, especially if you’re using the Hybrid method)
•Some improvements to diagnostics
oLower threshold for PSRF
oMore frequent reporting
oAdditional outputs in the stats file
•Additional output, including marginal distributions
•For convenience, an MCMC run generates a sensitivity control file to permit immediate use of the sample for sensitivity runs.
orunname_MCMC_sample.vsc can be used to run runname_MCMC_sample.tab
•A few changes are recommended to MCMC options
•The initialization phase is now fully parallel, making the Hybrid initialization method more usable.
Bayesian Inference
oNew payoff element type: pRior type ‘R’
▪Same behavior as a Policy (‘P’) element, but goes into a different accounting bucket
▪Use case:
▪Reporting prior and data likelihood contributions separately
▪Sampling from the prior, rather than the posterior (particularly for MCMC initialization step)
oIn addition, prior payoff terms are added from priors specified in the control file (.voc) parameter list
•Priors in the optimization control file
oYou can now specify priors directly in the parameter list
oPriors can use subscripts and hierarchy (hyperparameters)
•Payoff elements using the Poisson/Binomial family or logarithmic transform now add a large penalty term (1e12) if the model generates a value <= 0
•The scale term (weight) for the Poisson distribution can now be used for scaled Poisson
•New SYNTHETIC keyword for optimization control files simplifies generation of data, adding the error distribution assumed in the payoff to the model output
•Improved output in payoff reports
DSS only
The SyntheSim button can now load settings from any available run configurations and launch into SyntheSim
Presentation Mode
Model->Settings->General, "Start model in presentation mode". Presentation mode hides the toolbars and disables most of the menus. This is used when using an interface to run your model.
New Venapp commands
These new commands can be placed on buttons to use in an interface to run your model.
MENU>SIMCONTROL : This places the model into sim setup mode and displays the sim control dialog. This is for larger models that are not really suitable for SyntheSim. You can put the model into setup mode, make changes and then have another button to run the sim/sens/opt.
MENU>SIMSETUP : This places the model into sim setup mode without the sim control dialog. In this mode, you can change constants/lookups on the sketch. When using this mode, another button to execute any of the sim modes needs to be present (eg, MENU>RUN, MENU->SYNTHESIM, MENU>OPTIMIZE etc). If entering this mode, an optional runname editbox should be used to allow the run name to be changed. When MENU>RUN (etc) are executed from SIMSETUP mode, the run will be automatically overwritten (the logic for this is that during setup, you've set what you need to).
MENU>PRESENTATION_MODE{optional |1 or 0}
Sketch button setting
There is a new "Continue on error" setting for buttons that run VENAPP commands . The default is to stop on an error (for example, you have a series of commands (such as "start sim", then "navigate to a new view"), but if "start sim" fails (user clicks cancel when asked to overwrite a results file), you don't want to move to another screen. There are also times when you do want to continue if an error happens. You can find this setting under the GUI object setting dialog.
Sketch GUI objects
There have been a lot of additional functionality added to sketch GUI objects.
Parallel Simulation
There are several small performance improvements.
