TSPLIB | R Documentation |
Reads and writes TSPLIB format files. TSPLIB files can be used by most TSP solvers. Sample instances for the TSP in TSPLIB format are available on the TSPLIB homepage (see references).
read_TSPLIB(file, precision = 0)
write_TSPLIB(x, file, precision = 6, inf = NULL, neg_inf = NULL)
## S3 method for class 'TSP'
write_TSPLIB(x, file, precision = 6, inf = NULL, neg_inf = NULL)
## S3 method for class 'ATSP'
write_TSPLIB(x, file, precision = 6, inf = NULL, neg_inf = NULL)
## S3 method for class 'ETSP'
write_TSPLIB(x, file, precision = 6, inf = NULL, neg_inf = NULL)
file |
file name or a connection. |
precision |
controls the number of decimal places used to represent
distances (see details). If |
x |
an object with a TSP problem.
|
inf |
replacement value for |
neg_inf |
replacement value for |
In the TSPLIB format distances are represented by integer values. Therefore,
if x
contains double
values (which is normal in R) the values
given in x
are multiplied by 10^{precision}
before coercion to
integer
. Note that therefore all results produced by programs using
the TSPLIB file as input need to be divided by 10^{precision}
(i.e.,
the decimal point has to be shifted precision
placed to the left).
Currently only the following EDGE_WEIGHT_TYPE
s are implemented:
EXPLICIT
, EUC_2D
and EUC_3D
.
returns an object of class TSP
or
ATSP
.
Michael Hahsler
TSPLIB home page, http://comopt.ifi.uni-heidelberg.de/software/TSPLIB95/
Other TSP:
ATSP()
,
Concorde
,
ETSP()
,
TSP()
,
insert_dummy()
,
reformulate_ATSP_as_TSP()
,
solve_TSP()
## Drilling problem from TSP
drill <- read_TSPLIB(system.file("examples/d493.tsp", package = "TSP"))
drill
tour <- solve_TSP(drill, method = "nn", two_opt = TRUE)
tour
plot(drill, tour, cex=.6, col = "red", pch= 3, main = "TSPLIB: d493")
## Write and read data in TSPLIB format
x <- data.frame(x=runif(5), y=runif(5))
## create TSP, ATSP and ETSP (2D)
tsp <- TSP(dist(x))
atsp <- ATSP(dist(x))
etsp <- ETSP(x[,1:2])
write_TSPLIB(tsp, file="example.tsp")
#file.show("example.tsp")
r <- read_TSPLIB("example.tsp")
r
write_TSPLIB(atsp, file="example.tsp")
#file.show("example.tsp")
r <- read_TSPLIB("example.tsp")
r
write_TSPLIB(etsp, file="example.tsp")
#file.show("example.tsp")
r <- read_TSPLIB("example.tsp")
r
## clean up
unlink("example.tsp")
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