[R] Sum up the values of a function

From: Stefan Wagner <Stef.Wagner_at_students.uni-mannheim.de>
Date: Fri 10 Jun 2005 - 21:08:53 EST


Dear R-Users,

I have to do a maximum-likelihood estimation and have now a problem concerning how to sum up my function values in a smart way. I don't know how to explain it easyly, so I give you the code and show you where my problem is.
I have shorten the code a little bit, so that you only get the necessary facts:

ws12 <- function (z, i) (1/(1+exp(z[1]*(z[3]-x1[i]- z[4]*(m1[i]/n1[i]-0.5)))))
ws37 <- function (z, i) (1/(1+exp(z[2]*(z[3]-x2[i]- z[5]*(m2[i]/n2[i]-0.5)))))
wsAttack12 <- function (z,i) (ws12(z,i)*dec1[i]+(1-ws12(z,i))*(1-dec1[i]))
wsAttack37 <- function (z,i) (ws37(z,i)*dec2[i]+(1-ws37(z,i))*(1-dec2[i]))
logwsAttack12 <- function (z,i) (log(wsAttack12(z,i))) logwsAttack37 <- function (z,i) (log(wsAttack37(z,i))) ws12sum <- function (z)
(logwsAttack12(z,i=1)+logwsAttack12(z,i=2)+logwsAttack12(z,i=3)+logwsAttack12(z,i=4)+logwsAttack12(z,i=5)+logwsAttack12(z,i=6))
ws37sum <- function (z)
(logwsAttack37(z,i=1)+logwsAttack37(z,i=2)+logwsAttack37(z,i=3)+logwsAttack37(z,i=4)+logwsAttack37(z,i=5)+logwsAttack37(z,i=6)+logwsAttack37(z,i=7)+logwsAttack37(z,i=8))
wsLOG <- function (z) (ws12sum(z) + ws37sum(z)) LogSum <- function (z) (-sum(wsLOG(z)))
SP <- c(0.16, 0.10, 44, 0.80, 46)
out <- nlm (LogSum, p=SP)
out

For explanation: x1[i], x2[i], m1[i], m2[i], n1[i], n2[i] are given data and z[1:5] are my estimates.
My problem is that I have more than one session with diffent number of datas so that I am searching for a general way of summing up my logwsAttack12 and logwsAttack37. The program should recognize how many data are in my table concerning ws12 and how many concerning ws37 and should, in dependency of z, sum them up. I hope you understand my problem and hopefully someone is able to solve it. Many thanks for the moment.

Best regards,

Stefan Wagner



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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri Jun 10 21:22:35 2005

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