\documentclass[11pt]{article} \usepackage{graphicx} \usepackage{amssymb,amsmath} \usepackage{epstopdf} \DeclareGraphicsRule{.tif}{png}{.png}{`convert #1 `dirname #1`/`basename #1 .tif`.png} \textwidth = 6.5 in \textheight = 9 in \oddsidemargin = 0.0 in \evensidemargin = 0.0 in \topmargin = 0.0 in \headheight = 0.0 in \headsep = 0.0 in \parskip = 0.2in \parindent = 0.0in \newtheorem{theorem}{Theorem} \newtheorem{corollary}[theorem]{Corollary} \newtheorem{definition}{Definition} %\VignetteIndexEntry{Errata corrige to 1st edition of the companion book} \date{This version} \def\de{{\rm d}} \begin{document} {\it S.M. Iacus}. Errata Corrige to the first edition of: \\ Iacus, S.M. (2008) {\it Simulation and Inference for Stochastic Differential Equations: with R examples}, Springer Series in Statistics, Springer NY, ISBN: 978-0-387-75838-1. \\ \bigskip This version: {\bf 24-june-2009} \section*{Errata in Chapter 1} \begin{tabular}{lll} Where & Errata & Corrige\\ \hline \\ p:14, l:-22 &$(\omega, \mathcal A, P)$ & $(\Omega, \mathcal A, P)$\\ p:18, l:2 &$(\omega, \mathcal A, P)$& $(\Omega, \mathcal A, P)$\\ p.30, l:-2 &$\Pi_n\to 0$ & $||\Pi_n||\to 0$\\ p.36, l:-3 & $t \to -\infty$ & $t\to \infty$\\ p.39, l:3 & $O(\de t)$ & $o(\de t)$\\ p.39, f. (1.30) & $\displaystyle\left(b_1(s)-\frac12\sigma_1(s)\right)$ & $\displaystyle\left(b_1(s)-\frac12\sigma_1^2(s)\right)$ \\ p.42, l:11 & $b_1(x)=\nu$ & $b_1(x)=0$\\ p.42, l:12 & $b_2(x)=0$ &$b_2(x)=\nu$\\ \end{tabular}\\ p.42, central formula becomes $$ \begin{aligned} \frac{\de P_2}{\de P_1}(Y) &=\,\, \exp\left\{ \int_0^1 \frac{\nu-0}{\sigma^2}\de Y_s -\frac12 \int_0^1 \frac{\nu^2-0^2}{\sigma^2}\de t \right\}\\ &= \,\, \exp\left\{ \frac{\nu}{\sigma^2}\int_0^1(\nu \de s +\sigma \de W_s) - \frac12 \frac{\nu^2}{\sigma^2} \right\}\\ &= \,\, \exp\left\{ \left(\frac{\nu}{\sigma}\right)^2 + \frac{\nu}{\sigma} W_1 - \frac12 \frac{\nu^2}{\sigma^2} \right\}\\ &= \,\,\exp\left\{ \frac12 \left(\frac{\nu}{\sigma}\right)^2 + \frac{\nu W_1}{\sigma} \right\}\,. \end{aligned} $$ p.42, script ${\tt ex1.14.R}$ has changed to match this errata corrige in version 2.0.7 of the $\tt sde$ package. See below: \vspace{-0.5cm} {\scriptsize \begin{verbatim} # ex1.14.R -- corrected version. See errata corrige to the first edition set.seed(123) par("mar"=c(3,2,1,1)) par(mfrow=c(2,1)) npaths <- 30 N <- 1000 sigma <- 0.5 nu <- -0.7 X <- sde.sim(drift=expression(0),sigma=expression(0.5), pred=F, N=N,M=npaths) Y <- X + nu*time(X) girsanov <- exp(0.25 * (nu/sigma*X[N,] + 0.5*(nu/sigma)^2)) girsanov <- (girsanov - min(girsanov)) / diff(range(girsanov)) col.girsanov <- gray(1-girsanov) matplot(time(X),Y,type="l",lty=1, col="black",xlab="t") matplot(time(X),Y,type="l",lty=1,col=col.girsanov,xlab="t") \end{verbatim} } %\section*{Errata in Chapter 2} %\begin{itemize} %\item w %\end{itemize} \section*{Errata in Chapter 3} \begin{tabular}{lll} Where & Errata & Corrige\\ \hline \\ p:175, l:-7 & $f(y,x)$ & $f(x,y)$\\ p:176, l:10 & $f(y,x)$ & $f(x,y)$\\ p:177, l:9 & $f(y,x)$ & $f(x,y)$\\ \end{tabular} \par The following code for $\tt dcKessler$ had a missing square in term $\tt Ex$ in the definition of $\tt Vx$. \vspace{-0.5cm} {\scriptsize \begin{verbatim} dcKessler <- function (x, t, x0, t0, theta, d, dx, dxx, s, sx, sxx, log = FALSE){ Dt <- t - t0 mu <- d(t0, x0, theta) mu1 <- dx(t0, x0, theta) mu2 <- dxx(t0, x0, theta) sg <- s(t0, x0, theta) sg1 <- sx(t0, x0, theta) sg2 <- sxx(t0, x0, theta) Ex <- (x0 + mu * Dt + (mu * mu1 + 0.5 * (sg^2 * mu2)) * (Dt^2)/2) Vx <- (x0^2 + (2 * mu * x0 + sg^2) * Dt + (2 * mu * (mu1 * x0 + mu + sg * sg1) + sg^2 * (mu2 * x0 + 2 * mu1 + sg1^2 + sg * sg2)) * (Dt^2)/2 - Ex^2) Vx[Vx < 0] <- NA dnorm(x, mean = Ex, sd = sqrt(Vx), log = log) } \end{verbatim} } \section*{Errata in Chapter 4} p:213-214, Listing 4.3. The $\tt cpoint$ function has been fixed as follows in version 2.0.5 of the $\tt sde$ package. See below. \vspace{-0.5cm} {\scriptsize \begin{verbatim} function (x, mu, sigma) { DELTA <- deltat(x) n <- length(x) Z <- NULL if (!missing(mu) && !missing(sigma)) { Z <- (diff(x) - mu(x[1:(n - 1)]) * DELTA)/(sqrt(DELTA) * sigma(x[1:(n - 1)])) } else { bw <- n^(-1/5) * sd(x) y <- sapply(x[1:(n - 1)], function(xval) { tmp <- dnorm(xval, x[1:(n - 1)], bw) sum(tmp * diff(x))/(DELTA * sum(tmp)) }) Z <- diff(x)/sqrt(DELTA) - y * sqrt(DELTA) } lenZ <- length(Z) Sn <- cumsum(Z^2) S <- sum(Z^2) D <- abs(1:lenZ/lenZ - Sn/S) k0 <- which(D == max(D))[1] return(list(k0 = k0 + 1, tau0 = time(x)[k0 + 1], theta1 = sqrt(Sn[k0]/k0), theta2 = sqrt((S - Sn[k0])/(lenZ - k0)))) } \end{verbatim} } \section*{Updated references} \begin{itemize} \item[27.] Beskos, A., Papaspiliopoulos, O., Roberts, G.O. (2006) Retrospective exact simulation of diffusion sample paths with applications, {\it Bernoulli}, {\bf 12}(6), 1077--1098. \item[28.] Beskos, A., Papaspiliopoulos, O., Roberts, G.O. (2008) A Factorisation of Diffusion Measure and Finite Sample Path Constructions, {\it Meth. Compt. App. Prob.}, {\bf 10}(1), 85-104. \item[64.] De Gregorio, A., Iacus, S.M. (2008) Least squares volatility change point estimation for partially observed diffusion processes, {\it Communications in Statistics, Theory and Methods}, {\bf 37}(15), 2342--2357. \item[157.] Lepage, T., Law, S., Tupper, P., Bryant, D. (2006) Continuous and tractable models for the variation of evolutionary rates, {\it Math. Bioscences}, {\bf 199}(2), 216--233. \end{itemize} \section*{Acknowledgments} I'm thankful to Spencer Graves, Susanne Ditlevsen, Loretta Gasco for pointing out some of the above errata. \end{document}