Example1<-function(N,t_max){
#Example 1 in the manuscript Harman, Bachrata, Filova: Heuristic construction of exact experimental designs under multiple resource constraints
#block model with a constraint on the number of blocks
#input:
#N: the number of blocks
#t_max: the time (in seconds) the heuristic is required to run
#output:
#Phi_best: the D-value of the design w_best
#w_best: D-efficient exact design found by the heuristic

F<-matrix(0,nrow=16,ncol=120)
k<-1
for (t1 in 1:15){
	for (t2 in (t1+1):16){
		F[t1,k]<-1
		F[t2,k]<--1
		k<-k+1
	}
}

F<-F[1:15,]

res<-HugoR(F,N,rep(0,120),-1,t_max)
return(list(value=res$value,design=res$design))
}