lal::detail::crossings::ladder Namespace Reference

Namespace for the "ladder" algorithm to calculate \(C\). More...

Functions
template<bool decide_upper_bound, class graph_t , class arrangement_t >
uint64_t	compute (const graph_t &g, const arrangement_t &arr, unsigned char *const __restrict__ bn, uint64_t *const __restrict__ L1, const uint64_t upper_bound) noexcept
	Ladder computation of \(C\) for undirected graphs.

Detailed Description

Namespace for the "ladder" algorithm to calculate \(C\).

See [9].

Function Documentation

compute()

template<bool decide_upper_bound, class graph_t , class arrangement_t >

uint64_t lal::detail::crossings::ladder::compute ( const graph_t & g, const arrangement_t & arr, unsigned char *const __restrict__ bn, uint64_t *const __restrict__ L1, const uint64_t upper_bound )

nodiscardnoexcept

Ladder computation of \(C\) for undirected graphs.

When template parameter decide_upper_bound is false, the function returns the number of crossings.

Template Parameters

decide_upper_bound	Boolean value to choose the nature of the return type.
arrangement_t	Type of arrangement.

Parameters

g	Input graph.
arr	Input arrangement.
bn	Array of size n. Boolean neighbourhood of a vertex u: bn[i] is 1 if vertex u and vertex i are adjacent.
L1	See [9] for details.
upper_bound	Upper bound on the number of crossings.

Returns

When decide_upper_bound is true, the return value is:

• one unit larger than the upper bound passed as parameter if \(C>\) upper bound.
• \(C\) if the number of crossings is less or equal than the upper bound.