aa<-read.table("calorimeter.data",header=T)
xx.start<-c(tzero=120,base1=30,base2=-50,amp=30000,kinit=.2,kdecay=.01)
aa.out<-nls(voltage ~ (time < tzero)*(base1 - base2) + base2 + amp*(exp(-kinit*(time>=tzero)*(time-tzero)) - exp(-kdecay*(time>=tzero)*(time-tzero))), aa,start=xx.start,trace=TRUE)
#sink("scr.txt")
print(summary(aa.out))
#sink()
#postscript("scr.ps")
plot(aa$time,aa$voltage,xlab="time (seconds)",ylab="Voltage (nanovolts)",type="l")
title("Calorimeter Data")
lines(aa$time,fitted.values(aa.out),lty=2)
lines(10*(residuals(aa.out))-20000,lty=5)
text(600,-19000,"residuals x 10")
#graphics.off()