>From 69881c2d7792c59d8dfbed3a799186a95ef835fb Mon Sep 17 00:00:00 2001 From: Akira Yokosawa <akiyks@xxxxxxxxx> Date: Sat, 30 Sep 2017 17:37:45 +0900 Subject: [PATCH 02/10] debugging: Use upright font for Euler's number Also use \ln for natural logarithm. Signed-off-by: Akira Yokosawa <akiyks@xxxxxxxxx> --- debugging/debugging.tex | 24 ++++++++++++------------ perfbook.tex | 2 ++ 2 files changed, 14 insertions(+), 12 deletions(-) diff --git a/debugging/debugging.tex b/debugging/debugging.tex index 5747656..7a5f71d 100644 --- a/debugging/debugging.tex +++ b/debugging/debugging.tex @@ -1116,7 +1116,7 @@ is reassuring. \QuickQuiz{} In Equation~\ref{eq:debugging:Binomial Number of Tests Required}, - are the logarithms base-10, base-2, or base-$e$? + are the logarithms base-10, base-2, or base-$\euler$? \QuickQuizAnswer{ It does not matter. You will get the same answer no matter what base of logarithms @@ -1201,7 +1201,7 @@ The fundamental formula for failure probabilities is the Poisson distribution: \begin{equation} - F_m = \frac{\lambda^m}{m!} e^{-\lambda} + F_m = \frac{\lambda^m}{m!} \euler^{-\lambda} \label{eq:debugging:Poisson Probability} \end{equation} @@ -1225,14 +1225,14 @@ In this case, $\lambda$ is zero, so that Equation~\ref{eq:debugging:Poisson Probability} reduces to: \begin{equation} - F_0 = e^{-\lambda} + F_0 = \euler^{-\lambda} \end{equation} Solving this requires setting $F_0$ to 0.01 and solving for $\lambda$, resulting in: \begin{equation} - \lambda = - \log 0.01 = 4.6 + \lambda = - \ln 0.01 = 4.6 \end{equation} Because we get $0.3$ failures per hour, the number of hours required @@ -1246,11 +1246,11 @@ is a good and sufficient substitute for the Poisson distribution in a great many situations. More generally, if we have $n$ failures per unit time, and we want to -be P\,\% certain that a fix reduced the failure rate, we can use the +be $P$\,\% certain that a fix reduced the failure rate, we can use the following formula: \begin{equation} - T = - \frac{1}{n} \log \frac{100 - P}{100} + T = - \frac{1}{n} \ln \frac{100 - P}{100} \label{eq:debugging:Error-Free Test Duration} \end{equation} @@ -1287,14 +1287,14 @@ Equation~\ref{eq:debugging:Poisson Probability} as follows: \begin{equation} F_0 + F_1 + \dots + F_{m - 1} + F_m = - \sum_{i=0}^m \frac{\lambda^i}{i!} e^{-\lambda} + \sum_{i=0}^m \frac{\lambda^i}{i!} \euler^{-\lambda} \end{equation} This is the Poisson cumulative distribution function, which can be written more compactly as: \begin{equation} - F_{i \le m} = \sum_{i=0}^m \frac{\lambda^i}{i!} e^{-\lambda} + F_{i \le m} = \sum_{i=0}^m \frac{\lambda^i}{i!} \euler^{-\lambda} \label{eq:debugging:Possion CDF} \end{equation} @@ -1341,18 +1341,18 @@ that the fix actually had some relationship to the bug.\footnote{ Indeed it should. And it does. - To see this, note that $e^{-\lambda}$ does not depend on $i$, + To see this, note that $\euler^{-\lambda}$ does not depend on $i$, which means that it can be pulled out of the summation as follows: \begin{equation} - e^{-\lambda} \sum_{i=0}^\infty \frac{\lambda^i}{i!} + \euler^{-\lambda} \sum_{i=0}^\infty \frac{\lambda^i}{i!} \end{equation} The remaining summation is exactly the Taylor series for - $e^\lambda$, yielding: + $\euler^\lambda$, yielding: \begin{equation} - e^{-\lambda} e^\lambda + \euler^{-\lambda} \euler^\lambda \end{equation} The two exponentials are reciprocals, and therefore cancel, diff --git a/perfbook.tex b/perfbook.tex index 84e48eb..da9cfa8 100644 --- a/perfbook.tex +++ b/perfbook.tex @@ -137,6 +137,8 @@ \newcommand{\nf}[1]{\textnormal{#1}} % to return to normal font \newcommand{\qop}[1]{{\sffamily #1}} % QC operator such as H, T, S, etc. +\DeclareRobustCommand{\euler}{\ensuremath{\mathrm{e}}} + \newcommand{\Epigraph}[2]{\epigraphhead[65]{\rmfamily\epigraph{#1}{#2}}} \input{ushyphex} % Hyphenation exceptions for US English from hyphenex package -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe perfbook" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html