R: Add Constraint

add.constraint {lpSolveAPI} | R Documentation

## Add Constraint

### Description

Add a constraint to an lpSolve linear program model object.

### Usage

    add.constraint(lprec, xt, type = c("<=", "=", ">="), rhs, indices, lhs)

### Arguments

`lprec` | an lpSolve linear program model object.
`xt` | a numeric vector containing the constraint coefficients (only the nonzero coefficients if `indices` is also given). The length of `xt` must be equal to the number of decision variables in `lprec` unless `indices` is provided.
`type` | a numeric or character value from the set `{1 = "<=", 2 = ">=", 3 = "="}` specifying the type of the constraint.
`rhs` | a single numeric value specifying the right-hand-side of the constraint.
`indices` | optional for sparse `xt`. A numeric vector the same length as `xt` of unique values from the set {1, ..., n} where n is the number of decision variables in `lprec`; `xt[i]` is entered into column `indices[i]` in the added constraint. The coefficients for the columns not in `indices` are set to zero. This argument should be omitted when `length(xt) == n`.
`lhs` | optional. A single numeric value specifying the left-hand-side of the constraint.

### Details

Specifying the objective function before adding constraints will improve the performance of this function.

The use of this function should be avoided when possible. Building a model column-by-column rather than row-by-row will be on the order of 50 times faster (building the model - not solving the model).

### Value

a `NULL` value is invisibly returned.

### Author(s)

Kjell Konis kjell.konis@me.com

### References

http://lpsolve.sourceforge.net/5.5/index.htm

### Examples

    lps.model <- make.lp(0, 4)
    set.objfn(lps.model, rep(1, 4))
    add.constraint(lps.model, c(6,2,4,9), "<=", 50)
    add.constraint(lps.model, c(3,1,5), 2, 75, indices = c(1,2,4))

[Package lpSolveAPI version 5.5.2.0-17 Index]