cellular automaton_automaton储物柜_细胞自动机(3)

In their models, nodes were organised into blocks。 Nodes within a block were updated synchronously, but blocks were updated asynchronously。 They experimented with three schemes: (1) at each time step, a block is chosen at random with replacement; (2) at each time step, a block is chosen at random without replacement; (3) at each time step, a block is chosen according to a fixed update order。

There are different types of asynchronous updating, and different authors have described these in different ways. The schemes shown in the images below are as follows (Cornforth et al. 2005):

The synchronous scheme - all cells are updated in parallel at each time step. This is the conventional model, stated here for comparison.

The random independent scheme - at each time step, a cell is chosen at random with replacement, and updated.

The random order scheme - at each time step, all nodes are updated, but in random order.

The cyclic scheme - at each time step a node is chosen according to a fixed update order, which was decided at random during initialisation of the model.

The self-clocked scheme - each cell has an independent timer, initialised to a random period and phase. When the period has expired, the cell is updated and the timer reset. Updating is autonomous and proceeds at different rates for different cells.

The self-sync scheme - the same as the clocked scheme, but the phase of the timers are affected by local coupling to neiours, and so are able to achieve local synchrony.

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