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author | Ori Bernstein <ori@eigenstate.org> | 2021-06-14 00:00:37 +0000 |
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committer | Ori Bernstein <ori@eigenstate.org> | 2021-06-14 00:00:37 +0000 |
commit | a73a964e51247ed169d322c725a3a18859f109a3 (patch) | |
tree | 3f752d117274d444bda44e85609aeac1acf313f3 /sys/src/cmd/python/Doc/lib/libcmath.tex | |
parent | e64efe273fcb921a61bf27d33b230c4e64fcd425 (diff) |
python, hg: tow outside the environment.
they've served us well, and can ride off into the sunset.
Diffstat (limited to 'sys/src/cmd/python/Doc/lib/libcmath.tex')
-rw-r--r-- | sys/src/cmd/python/Doc/lib/libcmath.tex | 142 |
1 files changed, 0 insertions, 142 deletions
diff --git a/sys/src/cmd/python/Doc/lib/libcmath.tex b/sys/src/cmd/python/Doc/lib/libcmath.tex deleted file mode 100644 index 54e0cdb1f..000000000 --- a/sys/src/cmd/python/Doc/lib/libcmath.tex +++ /dev/null @@ -1,142 +0,0 @@ -\section{\module{cmath} --- - Mathematical functions for complex numbers} - -\declaremodule{builtin}{cmath} -\modulesynopsis{Mathematical functions for complex numbers.} - -This module is always available. It provides access to mathematical -functions for complex numbers. The functions are: - -\begin{funcdesc}{acos}{x} -Return the arc cosine of \var{x}. -There are two branch cuts: -One extends right from 1 along the real axis to \infinity, continuous -from below. -The other extends left from -1 along the real axis to -\infinity, -continuous from above. -\end{funcdesc} - -\begin{funcdesc}{acosh}{x} -Return the hyperbolic arc cosine of \var{x}. -There is one branch cut, extending left from 1 along the real axis -to -\infinity, continuous from above. -\end{funcdesc} - -\begin{funcdesc}{asin}{x} -Return the arc sine of \var{x}. -This has the same branch cuts as \function{acos()}. -\end{funcdesc} - -\begin{funcdesc}{asinh}{x} -Return the hyperbolic arc sine of \var{x}. -There are two branch cuts, extending left from \plusminus\code{1j} to -\plusminus-\infinity\code{j}, both continuous from above. -These branch cuts should be considered a bug to be corrected in a -future release. -The correct branch cuts should extend along the imaginary axis, -one from \code{1j} up to \infinity\code{j} and continuous from the -right, and one from -\code{1j} down to -\infinity\code{j} and -continuous from the left. -\end{funcdesc} - -\begin{funcdesc}{atan}{x} -Return the arc tangent of \var{x}. -There are two branch cuts: -One extends from \code{1j} along the imaginary axis to -\infinity\code{j}, continuous from the left. -The other extends from -\code{1j} along the imaginary axis to --\infinity\code{j}, continuous from the left. -(This should probably be changed so the upper cut becomes continuous -from the other side.) -\end{funcdesc} - -\begin{funcdesc}{atanh}{x} -Return the hyperbolic arc tangent of \var{x}. -There are two branch cuts: -One extends from 1 along the real axis to \infinity, continuous -from above. -The other extends from -1 along the real axis to -\infinity, -continuous from above. -(This should probably be changed so the right cut becomes continuous from -the other side.) -\end{funcdesc} - -\begin{funcdesc}{cos}{x} -Return the cosine of \var{x}. -\end{funcdesc} - -\begin{funcdesc}{cosh}{x} -Return the hyperbolic cosine of \var{x}. -\end{funcdesc} - -\begin{funcdesc}{exp}{x} -Return the exponential value \code{e**\var{x}}. -\end{funcdesc} - -\begin{funcdesc}{log}{x\optional{, base}} -Returns the logarithm of \var{x} to the given \var{base}. -If the \var{base} is not specified, returns the natural logarithm of \var{x}. -There is one branch cut, from 0 along the negative real axis to --\infinity, continuous from above. -\versionchanged[\var{base} argument added]{2.4} -\end{funcdesc} - -\begin{funcdesc}{log10}{x} -Return the base-10 logarithm of \var{x}. -This has the same branch cut as \function{log()}. -\end{funcdesc} - -\begin{funcdesc}{sin}{x} -Return the sine of \var{x}. -\end{funcdesc} - -\begin{funcdesc}{sinh}{x} -Return the hyperbolic sine of \var{x}. -\end{funcdesc} - -\begin{funcdesc}{sqrt}{x} -Return the square root of \var{x}. -This has the same branch cut as \function{log()}. -\end{funcdesc} - -\begin{funcdesc}{tan}{x} -Return the tangent of \var{x}. -\end{funcdesc} - -\begin{funcdesc}{tanh}{x} -Return the hyperbolic tangent of \var{x}. -\end{funcdesc} - -The module also defines two mathematical constants: - -\begin{datadesc}{pi} -The mathematical constant \emph{pi}, as a real. -\end{datadesc} - -\begin{datadesc}{e} -The mathematical constant \emph{e}, as a real. -\end{datadesc} - -Note that the selection of functions is similar, but not identical, to -that in module \refmodule{math}\refbimodindex{math}. The reason for having -two modules is that some users aren't interested in complex numbers, -and perhaps don't even know what they are. They would rather have -\code{math.sqrt(-1)} raise an exception than return a complex number. -Also note that the functions defined in \module{cmath} always return a -complex number, even if the answer can be expressed as a real number -(in which case the complex number has an imaginary part of zero). - -A note on branch cuts: They are curves along which the given function -fails to be continuous. They are a necessary feature of many complex -functions. It is assumed that if you need to compute with complex -functions, you will understand about branch cuts. Consult almost any -(not too elementary) book on complex variables for enlightenment. For -information of the proper choice of branch cuts for numerical -purposes, a good reference should be the following: - -\begin{seealso} - \seetext{Kahan, W: Branch cuts for complex elementary functions; - or, Much ado about nothing's sign bit. In Iserles, A., - and Powell, M. (eds.), \citetitle{The state of the art in - numerical analysis}. Clarendon Press (1987) pp165-211.} -\end{seealso} |