[hackers] [libzahl] Fix errors in the manual (most of them found by Ivan Zuboff) || Mattias Andrée
commit 781e9d05388539d989e3578ebc7f8a7cd038aeb0 Author: Mattias Andrée AuthorDate: Tue Nov 29 23:55:29 2016 +0100 Commit: Mattias Andrée CommitDate: Tue Nov 29 23:55:29 2016 +0100 Fix errors in the manual (most of them found by Ivan Zuboff) Signed-off-by: Mattias Andrée diff --git a/doc/arithmetic.tex b/doc/arithmetic.tex index 2e15a75..2c5a9d3 100644 --- a/doc/arithmetic.tex +++ b/doc/arithmetic.tex @@ -69,7 +69,7 @@ instruction specifically for performing addition with ripple-carry over multiple words, adds twos numbers plus the carry from the last addition. libzahl uses assembly to -implement this efficiently. If however, an +implement this efficiently. If, however, an assembly implementation is not available for the on which machine it is running, libzahl implements ripple-carry less efficiently @@ -80,8 +80,8 @@ the compiler is known to support this extension, it is implemented using inefficient pure C code. This last resort manually predicts whether an addition will overflow; -this could be made more efficent, but never -using the highest bit, in each character, +this could be made more efficient, by never +using the highest bit in each character, except to detect overflow. This optimisation is however not implemented because it is not deemed important enough and would @@ -100,9 +100,9 @@ in-place operation: \noindent Use this whenever possible, it will improve your performance, as it will involve less -CPU instructions for each character-addition +CPU instructions for each character addition and it may be possible to eliminate some -character-additions. +character additions. \newpage @@ -138,7 +138,7 @@ These function \emph{do not} allow {\tt NULL} for the output parameters: {\tt quotient} and {\tt remainder}. The quotient and remainder are calculated simultaneously and indivisibly, hence -{\tt zdivmod} is provided to calculated both, if +{\tt zdivmod} is provided to calculated both; if you are only interested in the quotient or only interested in the remainder, use {\tt zdiv} or {\tt zmod}, respectively. @@ -146,14 +146,14 @@ interested in the remainder, use {\tt zdiv} or These functions calculate a truncated quotient. That is, the result is rounded towards zero. This means for example that if the quotient is in -$(-1,~1)$, {\tt quotient} gets 0. That that, this +$(-1,~1)$, {\tt quotient} gets 0. That is, this % TODO try to clarify would not be the case for one of the sides of zero. For example, if the quotient would have been floored, negative quotients would have been rounded away from zero. libzahl only provides truncated -division, +division. -The remain is defined such that $n = qd + r$ after +The remainder is defined such that $n = qd + r$ after calling {\tt zdivmod(q, r, n, d)}. There is no difference in the remainer between {\tt zdivmod} and {\tt zmod}. The sign of {\tt d} has no affect @@ -188,7 +188,7 @@ lend you a hand. % Floored division \begin{alltt} - void \textcolor{c}{/* \textrm{All arguments most be unique.} */} + void \textcolor{c}{/* \textrm{All arguments must be unique.} */} divmod_floor(z_t q, z_t r, z_t n, z_t d) \{ zdivmod(q, r, n, d); @@ -199,7 +199,7 @@ lend you a hand. % Ceiled division \begin{alltt} - void \textcolor{c}{/* \textrm{All arguments most be unique.} */} + void \textcolor{c}{/* \textrm{All arguments must be unique.} */} divmod_ceiling(z_t q, z_t r, z_t n, z_t d) \{ zdivmod(q, r, n, d); @@ -214,7 +214,7 @@ lend you a hand. %commercial rounding \begin{alltt} /* \textrm{This is how we normally round numbers.} */ - void \textcolor{c}{/* \textrm{All arguments most be unique.} */} + void \textcolor{c}{/* \textrm{All arguments must be unique.} */} divmod_half_from_zero(z_t q, z_t r, z_t n, z_t d) \{ zdivmod(q, r, n, d); @@ -237,7 +237,7 @@ not award you a face-slap. % Had positive punishment % This rounding method is also called: % round half away from infinity \begin{alltt} - void \textcolor{c}{/* \textrm{All arguments most be unique.} */} + void \textcolor{c}{/* \textrm{All arguments must be unique.} */} divmod_half_to_zero(z_t q, z_t r, z_t n, z_t d) \{ zdivmod(q, r, n, d); @@ -254,7 +254,7 @@ not award you a face-slap. % Had positive punishment % This rounding method is also called: % round half towards positive infinity \begin{alltt} - void \textcolor{c}{/* \textrm{All arguments most be unique.} */} + void \textcolor{c}{/* \textrm{All arguments must be unique.} */} divmod_half_up(z_t q, z_t r, z_t n, z_t d) \{ int cmp; @@ -272,7 +272,7 @@ not award you a face-slap. % Had positive punishment % This rounding method is also called: % round half towards negative infinity \begin{alltt} - void \textcolor{c}{/* \textrm{All arguments most be unique.} */} + void \textcolor{c}{/* \textrm{All arguments must be unique.} */} divmod_half_down(z_t q, z_t r, z_t n, z_
[hackers] [libzahl] Fix errors in the manual (most of them found by Ivan Zuboff) || Mattias Andrée
commit aeb5e44a98cb4158528206c079654357b1c75b16 Author: Mattias Andrée AuthorDate: Wed Nov 30 10:15:59 2016 +0100 Commit: Mattias Andrée CommitDate: Wed Nov 30 10:15:59 2016 +0100 Fix errors in the manual (most of them found by Ivan Zuboff) Signed-off-by: Mattias Andrée diff --git a/doc/exercises.tex b/doc/exercises.tex index 3a9df19..9a18b99 100644 --- a/doc/exercises.tex +++ b/doc/exercises.tex @@ -596,7 +596,7 @@ ptest_llt(z_t n) $M_n$ is composite if $n$ is composite, therefore, if you do not expect prime-only values on $n$, the -performance can be improve by using some other +performance can be improved by using some other primality test (or this same test if $n$ is a Mersenne number) to first check that $n$ is prime. diff --git a/doc/miscellaneous.tex b/doc/miscellaneous.tex index 8750595..420d6a7 100644 --- a/doc/miscellaneous.tex +++ b/doc/miscellaneous.tex @@ -101,7 +101,7 @@ sum of a set of numbers. Another form of assignment available in libzahl is copy-assignment. This done using {\tt zset}. As easily observable, {\tt zset} is named like -{\tt zseti}, {\tt zsetu}, and {\tt zsetu}, but +{\tt zseti}, {\tt zsetu}, and {\tt zsets}, but without the input-type suffix. The lack of a input-type suffix means that the input type is {\tt z\_t}. {\tt zset} copies value of second diff --git a/doc/not-implemented.tex b/doc/not-implemented.tex index 59b3efb..9688189 100644 --- a/doc/not-implemented.tex +++ b/doc/not-implemented.tex @@ -3,25 +3,25 @@ In this chapter we maintain a list of features we have chosen not to implement, -but would fit into libzahl had we not have +but would fit into libzahl, had we not have our priorities straight. Functions listed herein will only be implemented if it is shown that it would be overwhelmingly advantageous. For each feature, a sample implementation or a mathematical expression -on which you can base your implemention -is included. The sample implementations create -temporary integer references, this is to -simplify the examples. You should try to -use dedicated variables; in case of recursion, -a robust program should store temporary -variables on a stack, so they can be -clean up if something happens. - -Research problems, like prime-factorisation -and discrete logarithms do not fit in the -scope of bignum libraries. % Unless they are extraordinarily bloated with vague mission-scope, like systemd. -And therefore do not fit into libzahl, +on which you can base your implementation is +included. The sample implementations create +temporary integer references to simplify the +examples. You should try to use dedicated +variables; in case of recursion, a robust +program should store temporary variables on +a stack, so they can be cleaned up if +something happens. + +Research problems, like prime factorisation +and discrete logarithms, do not fit in the +scope of bignum libraries % Unless they are extraordinarily bloated with vague mission-scope, like systemd. +and therefore do not fit into libzahl, and will not be included in this chapter. Operators and functions that grow so ridiculously fast that a tiny lookup table @@ -330,7 +330,7 @@ method can be derived from the observation \vspace{1em} \noindent -The resulting algorithm can be expressed +The resulting algorithm can be expressed as \begin{alltt} void @@ -690,10 +690,10 @@ in an integer, counting the sign bit: \end{alltt} \noindent -It requires a compiler extension, if missing, -there are other ways to computer the population -count for a word: manually bit-by-bit, or with -a fully unrolled +It requires a compiler extension; if it's not +available, there are other ways to computer the +population count for a word: manually bit-by-bit, +or with a fully unrolled \begin{alltt} int s; @@ -706,7 +706,7 @@ a fully unrolled \label{sec:Hamming distance} A simple way to compute the Hamming distance, -the number of differing bits, between two +the number of differing bits between two numbers is with the function \begin{alltt} @@ -767,13 +767,13 @@ side-effects. \label{sec:Reference duplication} This could be useful for creating duplicates -with modified sign. But only if neither +with modified sign, but only if neither {\tt r} nor {\tt a} will be modified whilst both are in use. Because it is unsafe, fairly simple to create an implementation with acceptable performance â {\tt *r = *a}, â and probably seldom useful, this has not -be implemented. +been implemented. \begin{alltt} void diff --git a/doc/number-theory.tex b/doc/number-theory.tex index 10c485b..b4c2ece 100644 --- a/doc/number-theory.tex +++ b/doc/number-theory.tex @@ -145,7 +145,7 @@ definion ensures \noindent and analogously for $\frac{b}{\gcd(a,\,b)}$. Note however, the convension $\gcd(0, 0) = 0$ is adhered. Therefore, -before dividing with $\gcd{a, b}$ you may want to check +before dividing with $\gcd(a, b)$ you may want to check whether $\gcd(a, b) = 0$.