Fratar provides a tool for modifying a matrix of values based upon a set of production and attraction factors for each of the zones in the matrix.

The application below provides an example of implementing a Doubly Constrained matrix expansion both using Fratar and using a looping process with explicit scripting in Matrix. The example is using the matrix and targets from Example 5.3 of the Ortuzar and Willumsen Modelling Transport book. The second method (using explicit scripting with Matrix) also provide the final cumulative balancing factors Ai and Bj.

communities.bentley.com/.../ex_5F00_DoublyConstr_5F00_GrowthFactors.zip

Other matrices and targets can be used by selecting them via catalog keys (note: the targets need to have the structure below in a DBF table).

 

Where Oi and Dj are the targets origin and destination totals.

Disclaimer: this is just an example, please contact us through our support portal (connect.bentley.com) for pointing out any observation.