You are here

Simile v5.0 released

What's new in Simile v5.0?

Released December 2007

Simile 5.0 has the same fast response time when editing very large models as when editing small ones, and builds even the largest models (over 2000 components) in around a minute. It has adaptive step size control, for more efficient model execution. There are also a large number of other improvements and bug fixes. Here is a list of some of the more significant improvements that have been made over Simile v4.9:

Diagram editor improvements

  • Responses are now fast, however complex the model.
  • Changes made to link routes and bowtie positions are now conserved approximately when moving their endpoints, rather than snapping back
  • Selecting 'Zoom to fit' now fits the whole model in the window, rather than just fitting one axis and keeping a scrollbar on the other
  • Enumerated type definitions are now saved with all submodels that need them, and a useful warning displayed if a submodel is loaded into a larger model with conflicting enumerated type definitions
  • If you select "Find..." from the context menu within a submodel, you will only be shown matching components within that submodel. Searching is also a lot faster.
  • Captions for clouds, which Simile only uses internally, now no longer appear in search results or prevent other components having the same caption
  • The hourglass no longer always displays when Simile is busy doing something, only things that might take longer than a fraction of a second, thus removing annoying flicker during drags etc.

Equation handling

  • Equations now have a larger font!

Model parameterization

  • After loading parameter values from datafiles, you can choose to have these values saved as raw binary in the scenario (.spf) file. This means that you no longer need to keep the datafiles with the model, and large array values reload a lot quicker because they do not need to be parsed.
  • A .csv datafile can now be read as a 2-D array of values, as an alternative to reading them as columns of indices and values
  • 2-D arrays can also be read from image files, GeoTIFF files and other data formats
  • The scenario file (.spf) is now in an XML-based format rather than base64-encoded, making it easier to edit with other tools while still being possible to send it by email etc

Model code generation

  • Time taken to generate code is now linear with respect to complexity of model
  • Absolute maximum model complexity has been roughly doubled
  • Some bugs relating to handling of units have been fixed

Model execution

  • We introduce adaptive step size control, which combines numerical accuracy with fast execution for 'stiff systems' problems such as the Lotka-Volterra predator-prey interaction model (ref.)
  • Models are now saved as packages by default, i.e., with their execution and visualization parameters and references to any datafiles needed. If it was executing when you saved it, it will start executing when you next open it.
  • For teaching and presentation purposes, you can now limit the execution speed of a model to make it easier to see what it is doing.

I/O Tools

  • You can now annotate I/O tool graphics with custom bits of text, to assist in model publication
  • The grid display tool can save its data as any of a range of file formats, including GeoTIFF. It uses an existing file of the same format as a template from which to copy georeferencing and other metadata into the new files. Saving can be on-demand or periodic.
  • There is a new object-oriented helper application interface using Itcl, making it simpler to write your own I/O tools. Old ones still work via a compatibility wrapper.
  • You no longer need to have a tabbed notebook in your run environment. It still appears initially, but you can delete all its pages and just use panes for your display tools.
  • Setting the value format in the table helper now works acceptably well
  • Popup boxes on I/O tool components can no longer lie off the screen.

Platform-specific issues

  • Earlier versions had potential problems (though none have been reported so far) on MacOS 10.5 (Leopard)
  • On Linux and MacOS it was possible to exit Simile while a dialogue box was displayed, which made it fail to exit properly. This has been taken care of.


  • The scripting interface has been overhauled so you can have multiple models open simultaneously
  • On opening a large model, the display zooms to the most recently edited part of the model, thus avoiding showing an empty window if there are no components in the default display position
  • When opening and saving files, Simile now keeps a separate directory context for each model desktop.
  • Option to export c++ code has been fixed (in the Enterprise edition)
  • You now get a more useful message if your model has been moved and some files it needs have not come with it
  • Fixed occasional problems with units in the new with_greatest function
  • Fixed a problem that stopped a model building if an equation referred in a certain order to a value in its parent model and a value from an association model in an exclusive role -- this affected the hex_levels catalogue model
  • Many even more minor bugs have been fixed, including removal of several irrelevant error messages.

Download Simile Version 5.0 now!



If you are interested in upgrading from v3.x or v4.x, we are offering existing Simile customers the special upgrade price of US$ 295 for the Standard Edition. Please contact

Page type: