function (delta.per.sigma=.5,t.treat=3, nrange=2:30,alpha=.05,power0=NULL) 
{
# delta.per.sigma is the ratio of delta over sigma for which 
# one wants to detect a delta shift in one mean while all other 
# means stay the same, or delta is the maximum difference 
# between any two means to be detected. t.treat is the number of 
# treatments. alpha is the desired significance level. nrange is a 
# range of sample sizes over which the power will be calculated
# for that delta.per.sigma. power0 is on optional value for the 
# target power that will be highlighted on the plot.
#------------------------------------------------------------------- 
lambda0=((t.treat-1)/t.treat)*delta.per.sigma^2
lambda1=delta.per.sigma^2/2

power=NULL
power1=NULL
for(n in nrange){
N=n*t.treat
Fcrit=qf(1-alpha,t.treat-1,N-t.treat)
power=c(power,1-pf(Fcrit,t.treat-1,N-t.treat,n*lambda0))
power1=c(power1,1-pf(Fcrit,t.treat-1,N-t.treat,n*lambda1))

}

plot(nrange,power,type="l",xlab=paste("minimum sample size n per each of t =",
      t.treat," treatments"),
      ylab="",ylim=c(0,1))
mtext(expression(beta(lambda)~"="~beta(n %*% lambda[0])),2,2.9,at=.6,col="red")
mtext(expression(beta(lambda)~"="~beta(n %*% lambda[1])),2,2.9,at=.25,col="blue")

abline(h=seq(0,1,.02),col="grey")
abline(v=nrange,col="grey")
lines(nrange,power,col="red",lwd=2)
lines(nrange,power1,col="blue",lwd=2)
title(substitute(over(Delta,sigma)==delta.per.sigma~","~alpha==alpha1~",  "~lambda[0]==bgroup("(",over(Delta,sigma),")")^2 %*%over(t-1,t)~",  "~
lambda[1]==over(1,2)%*%bgroup("(",over(Delta,sigma),")")^2,
list(alpha1=alpha,
delta.per.sigma=delta.per.sigma)))
if(!is.null(power0)){
  abline(h=power0,col="grey",lwd=2)
  par(las=2)
  mtext(substitute(beta==pow,list(pow=power0)),2,.2,at=power0,col="grey")
  par(las=0)
}
if(max(power1)>min(1-power)){
legend(x=c(mean(nrange)-.5*diff(range(nrange)),
mean(nrange)-.1*diff(range(nrange))),y=c(max(power)*.2,max(power)*.05),expression("all "~mu[i]~"are same, except for one, differing by"~phantom(0) %+-%  Delta,
max(list("("~mu[1],ldots,mu[t])~")")-min("("~list(mu[1],ldots,mu[t])~")")==Delta),col=c("red","blue"),lty=c(1,1),bg="white")
}else{
legend(x=c(mean(nrange)-.5*diff(range(nrange)),mean(nrange)-.1*diff(range(nrange))),
y=c(max(power)+max(1-power)/2,max(power)+max(1-power)*.38),expression("all "~mu[i]~"are same, except for one, differing by"~phantom(0) %+-%  Delta,
max(list("("~mu[1],ldots,mu[t])~")")-min("("~list(mu[1],ldots,mu[t])~")")==Delta),col=c("red","blue"),lty=c(1,1),bg="white")
}

}