inspect_mip {errorlocate}

inspect the mip problem formulation

Description

Utility function to inspect the mip problem for a record. inspect_mip can be used as a "drop-in" replacement for locate_errors(), but works on the first record.

Usage

inspect_mip(data, x, weight, ...)

Arguments

data

data to be checked

x

validation rules or errorlocalizer object to be used for finding possible errors.

weight

numeric optional weight specification to be used in the error localization (see expand_weights()).

...

optional parameters that are passed to lpSolveAPI::lp.control() (see details)

Details

It may sometimes be handy to find out what is happening exactly with a record. See the example section for finding out what to do with inspect_mip. See vignette("inspect_mip") for more details.

See Also

Other Mixed Integer Problem: MipRules-class

Examples

rules <- validator(x > 1)
data <- list(x = 0)
weight <- c(x = 1)

mip <- inspect_mip(data, rules)
print(mip)

# inspect the lp problem (prior to solving it with lpsolveAPI)
lp <- mip$to_lp()
print(lp)

# for large problems write the lp problem to disk for inspection
# lpSolveAPI::write.lp(lp, "my_problem.lp")

# solve the mip system / find a solution
res <- mip$execute()
names(res)

# lpSolveAPI status of finding a solution
res$s

# lp problem after solving (often simplified version of first lp)
res$lp

# records that are deemed "faulty"
res$errors

# values of variables used in the mip formulation. Also contains a valid solution
# for "faulty" variables
res$values

# see the derived mip rules and objective function, used in the construction of
# lp problem
mip$mip_rules()
mip$objective