createBoundBox {hitandrun}

Calculate a bounding box

Description

Calculate a bounding box around a polytope given by a set of linear constraints.

Usage

createBoundBox(constr, homogeneous=FALSE)

Arguments

constr

Constraint definition

homogeneous

Whether constr is given in homogeneous coordinate representation

Details

See har for a description of the constraint definition and the homogeneous coordinate representation.

This function uses findExtremePoints to find extreme points along each dimension.

Value

lb

Lower bound for each dimension (not including homogeneous coordinate).

ub

Upper bound for each dimension (not including homogeneous coordinate).

Author(s)

Gert van Valkenhoef

See Also

har

findExtremePoints

Examples

# constraints: x_1 >= 0, x_2 >= 0, x_1 + x_2 <= 1
A <- rbind(c(-1, 0), c(0, -1), c(1, 1))
b <- c(0, 0, 1)
d <- c("<=", "<=", "<=")
constr <- list(constr=A, rhs=b, dir=d)

bb <- createBoundBox(constr)
stopifnot(bb$lb == c(0.0, 0.0))
stopifnot(bb$ub == c(1.0, 1.0))