Table 7 Problem complexity.

From: An optimization model of tram timetables considering various signal priority strategies

Type

Variables of constraints

Theoretical dimension

Counts

Continuous variables

\({t}_{q, k}\)

\(\sum \left|K\right|\cdot \left|Q\right|\)

440

\({t}_{q, s}^{W}\), \({t}_{q,s}^{D}\),\({t}_{q,s}^{A}\)

\(\sum \left|S\right|\cdot \left|Q\right|\)

460

\({t}_{q,s}^{ot},\) \({t}_{q,s}^{rt}\),\({u}_{q,s},\)

\(\sum \left| {S^{\prime}} \right| \cdot \left| Q \right|\)

160

Binary

\({\alpha }_{q,b,s}\)

\(\sum \left|S\right|\cdot \left|Q\right|\)

460

\({\theta }_{b}^{s},\) \({\beta }_{b}^{s}\)

\(\sum \left| {S^{\prime}} \right| \cdot \left| Q \right|\)

160

Constraints

Constraints (1)

\(\sum \left|K\right|\cdot \left|Q\right|\)

440

Constraints (2)

\(\sum \left|\widetilde{S}\right|\cdot \left|Q\right|\)

140

Constraints (3)

\(\sum \left| {S^{\prime}} \right| \cdot \left| Q \right|\)

160

Constraints (4)

\(\sum \left| {S^{\prime\prime}} \right| \cdot \left| Q \right|\)

160

Constraints (5)

\(\sum \left|Q\right|\)

20

Constraints (6)–(7)

\(\sum \left|S\right|\cdot \left|Q\right|\)

460

Constraints (8)–(13)

\(\sum \left| {S^{\prime}} \right| \cdot \left| Q \right|\)

160

Constraints (14)

\(\sum \left|S\right|\cdot \left|Q\backslash \left\{\left|r\right|\right\}\right|\)

437