quadratic parameter of blvim() and grid_blvim() has been replaced
by the more flexible algorithm parameter.Most of the new features are based on the potential introduced by Osawa, Akamatsu, and Kogure in a recent paper (https://arxiv.org/abs/2011.06778v2).
sim_potential() computes the potential of spatial interaction model using
the definition proposed by Osawa, Akamatsu, and Kogure.blvim() and grid_blvim() now support multiple ways to specify the initial
values of the attractivenesses of the destination locations. In particular
an automated balanced vector of values is used when the initial
attractivenesses are not provided. When multiple initial configurations are
provided, the functions select the best one, that is the one with the largest
potential.blvim() and grid_blvim() can now be generated by
arbitrary generators, using the new function blvim_initialise() to specify
the generator and its parameters. The default blvim_simplex_initialise()
uses the new function sample_weighted_simplex() to sample in a structured
way the simplex associated to the spatial interaction model.blvim() and grid_blvim() now support two new algorithms to find an
equilibrium. Both are instance of a projected gradient ascent approach.sim_diagnostic() gives details about the behaviour of the iterative
algorithms for blvim() while blvim_gradient_control() can be used to set
the parameters of the line search used in the projected gradient ascent
methods.blvim() and grid_blvim() now support conversion factors between
attractivenesses and incoming flows, together with the new function
sim_conversion().sim_fp_jacobian() computes the Jacobian of the fixed point map with respect
to the attractivenesses.grid_autoplot() to have them run in less than 5
seconds.