XAG algebraic rewriting

Header: mockturtle/algorithms/xag_algebraic_rewriting.hpp

Parameters

struct xag_algebraic_depth_rewriting_params

Parameters for xag_algebraic_depth_rewriting.

The data structure xag_algebraic_depth_rewriting_params holds configurable parameters with default arguments for xag_algebraic_depth_rewriting.

Public Types

enum strategy_t

Rewriting strategy.

Values:

enumerator dfs

DFS rewriting strategy.

Applies depth rewriting once to all output cones whose drivers have maximum levels

enumerator aggressive

Aggressive rewriting strategy.

Applies depth reduction multiple times until the number of nodes, which cannot be rewritten, matches the number of nodes, in the current network; or the new network size is larger than the initial size w.r.t. to an overhead.

enumerator selective

Selective rewriting strategy.

Like aggressive, but only applies rewriting to nodes on critical paths and without overhead.

Public Members

float overhead = {2.0f}

Overhead factor in aggressive rewriting strategy.

When comparing to the initial size in aggressive depth rewriting, also the number of dangling nodes are taken into account.

bool allow_area_increase = {true}

Allow area increase while optimizing depth.

bool allow_rare_rules = {false}

Try rules that are rarely applied.

Algorithm

template<class Ntk>
void mockturtle::xag_algebraic_depth_rewriting(Ntk &ntk, xag_algebraic_depth_rewriting_params const &ps = {})

XAG algebraic depth rewriting.

This algorithm tries to rewrite a network with AND/XOR gates for depth optimization using the associativity and distributivity rule in AND-XOR logic. It can be applied to networks other than XAGs, but only considers pairs of nodes which both implement the AND function and the XOR function.

Required network functions:

• get_node

• level

• update_levels

• create_and

• create_xor

• substitute_node

• foreach_node

• foreach_po

• foreach_fanin

• is_and

• is_xor

• clear_values

• set_value

• value

• fanout_size