#########################################################
#### 2 sample, discrete hazard (binomial) type EL.  #####
#### constraint parameter=Difference of 2 intHaz.   #####
#########################################################
emplikH2B <- function(lambda, x1, d1, x2, d2, fun1, fun2, CIforTheta=FALSE) {

    n1 <- length(x1)
    if (n1 <= 2) stop("Need more observations for sample 1")
    if (length(d1) != n1) stop("length of x1 and d1 must agree")
    if (any((d1 != 0) & (d1 != 1))) stop("d1 must be 0/1's for censor/not-censor")
    if (!is.numeric(x1)) stop("x1 must be numeric values -- observed times")
    if (!is.numeric(lambda)) stop("lambda must be a numeric value, the tilt")

    newdata1 <- Wdataclean2(z=x1, d=d1)
    temp1 <- DnR(newdata1$value, newdata1$dd, newdata1$weight)
    jump1 <- (temp1$n.event)/temp1$n.risk

    index1 <- (jump1 < 1)
    eve1 <- temp1$n.event[index1]
    tm1 <- temp1$times[index1]
    rsk1 <- temp1$n.risk[index1]
    jmp1 <- jump1[index1]
    k1 <- rsk1 - eve1
    funtime1 <- fun1(tm1)
    funh1 <- funtime1/rsk1

########Sample two########
    n2 <- length(x2)
    if (n2 <= 2) stop("Need more observations for sample 2")
    if (length(d2) != n2) stop("length of x2 and d2 must agree")
    if (any((d2 != 0) & (d2 != 1))) stop("d2 must be 0/1's for censor/not-censor")
    if (!is.numeric(x2)) stop("x2 must be numeric values -- observed times")

    newdata2 <- Wdataclean2(z=x2, d=d2)
    temp2 <- DnR(newdata2$value, newdata2$dd, newdata2$weight)
    jump2 <- (temp2$n.event)/temp2$n.risk
    index2 <- (jump2 < 1)
    eve2 <- temp2$n.event[index2]
    tm2 <- temp2$times[index2]
    rsk2 <- temp2$n.risk[index2]
    jmp2 <- jump2[index2]
    k2 <- rsk2 - eve2
    funtime2 <- fun2(tm2)
    funh2 <- funtime2/rsk2

    lam <- lambda
######## constrain function ########
inthaz <- function(lam, funt1, evt1, rsk1, funt2, evt2, rsk2) {
 sum(funt1*log(1-(evt1/(rsk1+lam*funt1)))) -
 sum(funt2*log(1-(evt2/(rsk2-lam*funt2)))) }

HazD <- NA
if(CIforTheta) {
HazD <- inthaz(lam, funtime1, eve1, rsk1, funtime2, eve2, rsk2)
}
 onePlam <- 1+lam*funh1
 weights1 <- jmp1/onePlam
 oneMlam <- 1-lam*funh2
 weights2 <- jmp2/oneMlam

 loglik1 <- sum(eve1*log(onePlam))+sum((k1)*log((1-jmp1)/(1-weights1)))
 loglik2 <- sum(eve2*log(oneMlam))+sum((k2)*log((1-jmp2)/(1-weights2)))
 loglikR <- 2*(loglik1+loglik2)

list("-2LLR" = loglikR, lambda = lam, times1 = tm1, times2=tm2,
     wts1 = weights1, wts2 = weights2, HazDiff2=HazD)
}