## Variable ordering options

The variable ordering used by the CIF data-based synthesis tool can be configured through options. There are two ways to configure variable ordering:

- Basic configuration using basic options.

- Advanced configuration using an advanced option.

These options allow configuring the variable order to one of several predefined orders, or to a custom variable order. Manually specifying a custom order often requires specialist knowledge and can take quite some time. Luckily, there are algorithms that can automatically compute a decent variable order by improving an existing variable order. The algorithms to apply, and their settings, can be set using options as well.

The following basic options are available for basic configuration of variable ordering:

- BDD initial variable ordering

- BDD hyper-edge creation algorithm

- BDD DCSH variable ordering algorithm

- BDD FORCE variable ordering algorithm

- BDD sliding window variable ordering algorithm

- BDD sliding window size

For more information on the use of these basic options, see:

- Initial variable orders

- Automatic variable ordering

For more flexibility, variable ordering can instead be configured using an advanced option:

- Advanced variable ordering configuration

Variable ordering may be configured using either the basic options or using the advanced option. It is not supported to configure variable ordering using both basic and advanced configuration at the same time.