View source: R/add_rsymphony_solver.R
add_rsymphony_solver  R Documentation 
Specify that the SYMPHONY software – using the Rsymphony package – should be used to solve a conservation planning problem (Ralphs & Güzelsoy 2005). This function can also be used to customize the behavior of the solver. It requires the Rsymphony package to be installed.
add_rsymphony_solver(
x,
gap = 0.1,
time_limit = .Machine$integer.max,
first_feasible = FALSE,
verbose = TRUE
)
x 

gap 

time_limit 

first_feasible 

verbose 

SYMPHONY is an opensource mixed integer programming solver that is part of the Computational Infrastructure for Operations Research (COINOR) project. The Rsymphony package provides an interface to COINOR and – unlike dependencies for other solvers – is available on CRAN. For information on the performance of different solvers, please see Schuster et al. (2020) for benchmarks comparing the run time and solution quality of different solvers when applied to different sized datasets.
An updated problem()
object with the solver added to it.
Ralphs TK and Güzelsoy M (2005) The SYMPHONY callable library for mixed integer programming. In The Next Wave in Computing, Optimization, and Decision Technologies (pp. 61–76). Springer, Boston, MA.
Schuster R, Hanson JO, StrimasMackey M, and Bennett JR (2020). Exact integer linear programming solvers outperform simulated annealing for solving conservation planning problems. PeerJ, 8: e9258.
See solvers for an overview of all functions for adding a solver.
Other solvers:
add_cbc_solver()
,
add_cplex_solver()
,
add_default_solver()
,
add_gurobi_solver()
,
add_highs_solver()
,
add_lsymphony_solver
## Not run:
# load data
sim_pu_raster < get_sim_pu_raster()
sim_features < get_sim_features()
# create problem
p <
problem(sim_pu_raster, sim_features) %>%
add_min_set_objective() %>%
add_relative_targets(0.1) %>%
add_binary_decisions() %>%
add_rsymphony_solver(time_limit = 10, verbose = FALSE)
# generate solution
s < solve(p)
# plot solution
plot(s, main = "solution", axes = FALSE)
## End(Not run)
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