Vensim 6.3 is available for download or purchase in the Vensim Store.
for details and downloads, including the free PLE and Model Reader.
6.3 emphasizes engine improvements that keep Vensim #1 when it comes to industrial strength simulation:
Random Numbers & Sampling
A new pseudorandom number generator, extensively tested with the Statistical Test Suite from the National Institute of Standards – great for financial, stochastic or statistical models that are heavy consumers of random numbers.
Optimization and sensitivity control files may now specify a random seed of 0 to trigger randomization to system cryptographic sources (useful for performing independent runs on multiple computers without editing the control files).
Improved sampling for Sensitivity (Monte Carlo) Simulations.
Big improvements to Markov Chain Monte Carlo and Simulated Annealing performance
A broader distribution of initial test points in random multistart optimization (MWYS), to find optimal solutions faster (up to 100x in one test case).
Improved speed in stochastic optimization, with support for the File sensitivity control option.
There are also some usability upgrades, like better number formatting and placement of the workbench variable in the bottom status toolbar.Vensim 64
A 64-bit beta version is available for download to Vensim Pro and DSS users who are current with their maintenance. It’s full-featured and supports huge models.Vensim 6
If you’re not current with Vensim 6, there are some valuable new features, including:
Native Mac support (licenses are portable across platforms)
GET DIRECT functions that can access spreadsheets and other delimited data files, like the GET XLS functions without the overhead of launching Excel.
Significant upgrades to the Help system, including improved indexing and nearly 100 sample models illustrating the use of almost every built-in function
A new Equation Editor
Improved Toolbars and Cursors
The option of observing integer constraints in the ALLOCATE AVAILABLE function – great for managing allocation of discrete items like customers or aircraft.
On-the-fly configuration of subscripts (arrays) with the GET DIRECT SUBSCRIPTS or GET ODBC SUBSCRIPTS functions – great for matching model detail to your data.
:EXCEPT: statements that let you handle exceptions to subscripted equations more easily.
Stochastic optimization : optimize over an ensemble of Monte Carlo simulations
Discrete constraints on optimization parameters, so you don’t waste time determining whether to build 2.6 or 2.7 factories.
Extended payoffs with non-Gaussian errors, logarithms, and mixed calibration/policy variables.
Markov chain Monte Carlo & simulated annealing
Extended payoff report information with MAPE and Theil statistics
Feedback from our users who’ve upgraded to version 6 has been highly positive. Contact us for details on any of these.The Next Great Thing
This summer, we will be showing an exciting new product that will help you build better models of complex systems.
Key benefits are:
• Hierarchy and object orientation, supporting sectors and complex agents, with no arcane arrays
• Dynamic creation and deletion of model components and relationships
• Support for team collaboration, model federation and submodels
• Advanced graphics and a new, clean look
• Just like Vensim, a pure declarative language (no programming)
Please stop by and visit us at the Ventana/Greenwood table during the System Dynamics conference. Or, come to the Vensim user’s group meeting and our Thursday workshops on Vensim and building entity-based system dynamics models. We look forward to seeing you in Delft!