you are trying to square an expression not an number! try this:
h.fun <- function(tt) ((tt/d1)^a1) * exp(-(tt-d1)/b1) - cc*((tt/d2)^a2) * exp(-(tt-d2)/b2)
h <- h.fun(tt) h <- h/sqrt(sum(h*h))
I hope it helps.
Best, Dimitris
---- Dimitris Rizopoulos Ph.D. Student Biostatistical Centre School of Public Health Catholic University of Leuven
Address: Kapucijnenvoer 35, Leuven, Belgium Tel: +32/16/336899 Fax: +32/16/337015 Web: http://www.med.kuleuven.ac.be/biostat/ http://www.student.kuleuven.ac.be/~m0390867/dimitris.htm
----- Original Message ----- From: "Christoph Lehmann" <[EMAIL PROTECTED]>
To: <R-help@stat.math.ethz.ch>
Sent: Tuesday, February 15, 2005 3:45 PM
Subject: [R] matlab norm(h) command in R: sqrt(sum(h^2)) - use in anexpression
Hi
in matlab I defined a function (double gamma, parameters at the end of this mail) as
h(i)=((t/d1)^a1)*exp(-(t-d1)/b1)-c*((t/d2)^a2)*exp(-(t-d2)/b2);
h=h/norm(h);
I do know that norm() in matlab is equal to:
sqrt(sum(x^2)) in R so in R I do it like:
#function (double gamama)
h <- expression((t/d1)^a1*exp(-(t-d1)/b1)-c*(t/d2)^a2*exp(-(t-d2)/b2))
# plot it t <- seq(0, 20000, by = 100) t <- t/1000 plot(eval(h), type = 'l')
# however this yields an error h <- h/sqrt(sum(h^2)) Error in h^2 : non-numeric argument to binary operator
what shall I do to get the matlab: h = h/norm(h) implemented in R?
thanks for a hint
christoph
---- # parameters peak1 <- 5.4 fwhm1 <- 5.2 peak2 <- 10.8 fwhm2 <- 7.35 dip <- 0.35
b1 <- 0.9 # dispersion b2 <- 0.9 #dispersion a1 <- peak1/b1 a2 <- peak2/b2 d1 <- a1*b1 d2 <- a2*b2 c <- dip
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