TSPLIB {TSP} | 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).
write_TSPLIB(x, file, precision = 6, inf = NULL, neg_inf = NULL) read_TSPLIB(file, precision = 0)
x |
an object of class TSP or ATSP . |
file |
file name or a connection . |
precision |
controls the number of decimal places used to represent
distances (see details). If x already is integer , this
argument is ignored and x is used as is. |
inf |
replacement value for Inf (TSPLIB format cannot handle
Inf ). If inf is NULL , the default value of 2 times
the maximum value in x (ignoring the infinity entries) is used. |
neg_inf |
replacement value for -Inf .
If no value is specified, the default value of
2 times the smalles neg. number is used.
If x only contains positive
values, -1 is used. |
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).
read_TSPLIB
returns an object of class TSP
or ATSP
.
TSPLIB home page, http://www.iwr.uni-heidelberg.de/groups/comopt/software/TSPLIB95/