tests/test_cccp.R

In ROI.plugin.cccp: 'ccp' Plug-in for the 'R' Optimization Infrastructure

Sys.setenv(ROI_LOAD_PLUGINS = FALSE)
library(ROI)
library(ROI.plugin.cccp)

check <- function(domain, condition, level=1, message="", call=sys.call(-1L)) {
    if ( isTRUE(condition) ) return(invisible(NULL))
    msg <- sprintf("in %s", domain)
    if ( all(nchar(message) > 0) ) msg <- sprintf("%s\n\t%s", msg, message)
    stop(msg)
    return(invisible(NULL))
}

## LP - Example - 1
## max:  2 x_1 + 4 x_2 + 3 x_3
## s.t.
## 3 x_1  +  4 x_2  +  2 x_3  <= 60
## 2 x_1  +    x_2  +  2 x_3  <= 40
##   x_1  +  3 x_2  +  2 x_3  <= 80 
## x_1, x_2, x_3 >= 0
test_lp_01 <- function(solver) {
    mat <- matrix(c(3, 4, 2,
                    2, 1, 2,
                    1, 3, 2), nrow=3, byrow=TRUE)
    x <- OP(objective = c(2, 4, 3),
            constraints = L_constraint(L = mat,
                                       dir = c("<=", "<=", "<="),
                                       rhs = c(60, 40, 80)),
            maximum = TRUE)


    opt <- ROI_solve(x, solver = solver)
    check("LP-01@01", equal(opt$solution, c(0, 20/3, 50/3), tol=1e-4))
    check("LP-01@02", equal(opt$objval, 230/3, tol=1e-4))
}

## Test if ROI can handle empty constraint matrix.
test_lp_02 <- function(solver) {
    x <- OP(objective = c(2, 4, 3),
            constraints = L_constraint(L=matrix(0, nrow=0, ncol=3), 
                                       dir=character(), rhs=double()),
            maximum = FALSE)

    opt <- ROI_solve(x, solver = solver)
    check("LP-02@01", equal(opt$solution, c(0, 0, 0), tol=1e-4))
    check("LP-02@02", equal(opt$objval, 0, tol=1e-4))
}

## Test if ROI can handle when the constraint is equal to NULL.
test_lp_03 <- function(solver) {
    x <- OP(objective = c(2, 4, 3), constraints = NULL, maximum = FALSE)

    opt <- ROI_solve(x, solver = solver)
    check("LP-03@03", equal(opt$solution, c(0, 0, 0), tol=1e-4))
    check("LP-03@03", equal(opt$objval, 0, tol=1e-4))
}


## QP - Example - 1
##
## from the quadprog package
## (c) S original by Berwin A. Turlach R port by Andreas Weingessel
## GPL-3
##
## min: -(0 5 0) %*% x + 1/2 x^T x
## under the constraints:      A^T x >= b
## with b = (-8,2,0)^T
## and      (-4  2  0)
##      A = (-3  1 -2)
##          ( 0  0  1)
## we can use solve.QP as follows:
##
## library(quadprog)
## D <- diag(1, 3)
## d <- c(0, 5, 0)
## A <- cbind(c(-4, -3, 0), 
##            c( 2,  1, 0), 
##            c( 0, -2, 1))
## b <- c(-8, 2, 0)
## 
## sol <- solve.QP(D, d, A, bvec=b)
## deparse(sol$solution)
## deparse(sol$value)
test_qp_01 <- function(solver) {
    A <- cbind(c(-4, -3, 0), 
               c( 2,  1, 0), 
               c( 0, -2, 1))
    x <- OP(Q_objective(diag(3), L =  c(0, -5, 0)),
            L_constraint(L = t(A),
                         dir = rep(">=", 3),
                         rhs = c(-8, 2, 0)))

    opt <- ROI_solve(x, solver=solver)
    x.solution <- c(0.476190476190476, 1.04761904761905, 2.0952380952381)
    check("QP-01@01", equal(opt$solution, x.solution, tol=1e-4) )
    check("QP-01@02", equal(opt$objval, -2.38095238095238) )
}

## This Test detects non-conform objective functions.
## minimize 0.5 x^2 - 2 x + y
## s.t. x <= 3
## Type 1:   0.5 x'Qx + c'Lx => c(2, 0)  objval=-2
## Type 2:       x'Qx + c'Lx => c(3, 0)  objval=-3.75
test_qp_02 <- function(solver) {
    zero <- .Machine$double.eps * 100
    qo <- Q_objective(Q=rbind(c(1, 0), c(0, zero)), L=c(-2, 1))
    lc1 <- L_constraint(L=matrix(c(1, 0), nrow=1), dir="<=", rhs=3)
    lc2 <- L_constraint(L=matrix(c(1, 0), nrow=1), dir=">=", rhs=0)
    x <- OP(qo, c(lc1, lc2))

    opt <- ROI_solve(x, solver=solver)
    x.solution <- c(2, 0)
    check("QP-02@01", equal(opt$solution, x.solution, tol=1e-4) )
    check("QP-02@02", equal(opt$objval, -2, tol=1e-4) )
}


if ( !any("cccp" %in% names(ROI_registered_solvers())) ) {
    ## This should never happen.
    cat("ROI.plugin.cccp cloud not be found among the registered solvers.\n")
} else {
    print("Start Testing!")
    local({test_lp_01("cccp")})
    local({test_lp_02("cccp")})
    local({test_lp_03("cccp")})
    ## local({test_qp_01("cccp")})
    ## local({test_qp_02("cccp")})
}