I would like to plot multiple random walks onto the same graph. My p variable dictates how may random walks there will be.
par(mfrow=c(1,1)) p <- 100 N <- 1000 S0 <- 10 mu <- 0.03 sigma <- 0.2 nu <- mu-sigma^2/2 x <- matrix(rep(0,(N+1)*p),nrow=(N+1)) y <- matrix(rep(0,(N+1)*p),nrow=(N+1)) t<- (c(0:N))/N for (j in 1:p) { z <- rnorm(N,0,1) x[1,j] <- 0 y[1,j] <- S0 for (i in 1:N) { x[i+1,j] <- (1/sqrt(N))*sum(z[1:i]) y[i+1,j] <- y[1,j]*exp(nu*t[i+1]+sigma*x[i+1,j]) } plot(t,y,type="l",xlab="time", ylab="Geometric Brownian motion") } Any help would be appreciated, thanks. -- View this message in context: http://r.789695.n4.nabble.com/simple-loop-problemo-Geo-brownian-motion-tp3050762p3050762.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.