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numbers" instead; we have not described "reals" anywhere else in the documentation, and this is not the place to change the story! Reported by Keith Briggs <keith.briggs@bt.com>.
141 lines
3.8 KiB
TeX
141 lines
3.8 KiB
TeX
\section{\module{math} ---
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Mathematical functions}
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\declaremodule{builtin}{math}
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\modulesynopsis{Mathematical functions (\function{sin()} etc.).}
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This module is always available. It provides access to the
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mathematical functions defined by the C standard.
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These functions cannot be used with complex numbers; use the functions
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of the same name from the \refmodule{cmath} module if you require
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support for complex numbers. The distinction between functions which
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support complex numbers and those which don't is made since most users
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do not want to learn quite as much mathematics as required to
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understand complex numbers. Receiving an exception instead of a
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complex result allows earlier detection of the unexpected complex
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number used as a parameter, so that the programmer can determine how
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and why it was generated in the first place.
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The following functions provided by this module:
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\begin{funcdesc}{acos}{x}
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Return the arc cosine of \var{x}.
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\end{funcdesc}
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\begin{funcdesc}{asin}{x}
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Return the arc sine of \var{x}.
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\end{funcdesc}
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\begin{funcdesc}{atan}{x}
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Return the arc tangent of \var{x}.
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\end{funcdesc}
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\begin{funcdesc}{atan2}{y, x}
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Return \code{atan(\var{y} / \var{x})}.
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\end{funcdesc}
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\begin{funcdesc}{ceil}{x}
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Return the ceiling of \var{x} as a float.
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\end{funcdesc}
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\begin{funcdesc}{cos}{x}
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Return the cosine of \var{x}.
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\end{funcdesc}
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\begin{funcdesc}{cosh}{x}
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Return the hyperbolic cosine of \var{x}.
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\end{funcdesc}
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\begin{funcdesc}{exp}{x}
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Return \code{e**\var{x}}.
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\end{funcdesc}
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\begin{funcdesc}{fabs}{x}
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Return the absolute value of the floating point number \var{x}.
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\end{funcdesc}
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\begin{funcdesc}{floor}{x}
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Return the floor of \var{x} as a float.
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\end{funcdesc}
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\begin{funcdesc}{fmod}{x, y}
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Return \code{fmod(\var{x}, \var{y})}, as defined by the platform C library.
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Note that the Python expression \code{\var{x} \%\ \var{y}} may not return
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the same result.
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\end{funcdesc}
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\begin{funcdesc}{frexp}{x}
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% Blessed by Tim.
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Return the mantissa and exponent of \var{x} as the pair
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\code{(\var{m}, \var{e})}. \var{m} is a float and \var{e} is an
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integer such that \code{\var{x} == \var{m} * 2**\var{e}}.
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If \var{x} is zero, returns \code{(0.0, 0)}, otherwise
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\code{0.5 <= abs(\var{m}) < 1}.
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\end{funcdesc}
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\begin{funcdesc}{hypot}{x, y}
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Return the Euclidean distance, \code{sqrt(\var{x}*\var{x} + \var{y}*\var{y})}.
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\end{funcdesc}
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\begin{funcdesc}{ldexp}{x, i}
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Return \code{\var{x} * (2**\var{i})}.
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\end{funcdesc}
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\begin{funcdesc}{log}{x}
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Return the natural logarithm of \var{x}.
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\end{funcdesc}
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\begin{funcdesc}{log10}{x}
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Return the base-10 logarithm of \var{x}.
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\end{funcdesc}
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\begin{funcdesc}{modf}{x}
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Return the fractional and integer parts of \var{x}. Both results
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carry the sign of \var{x}. The integer part is returned as a float.
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\end{funcdesc}
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\begin{funcdesc}{pow}{x, y}
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Return \code{\var{x}**\var{y}}.
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\end{funcdesc}
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\begin{funcdesc}{sin}{x}
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Return the sine of \var{x}.
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\end{funcdesc}
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\begin{funcdesc}{sinh}{x}
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Return the hyperbolic sine of \var{x}.
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\end{funcdesc}
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\begin{funcdesc}{sqrt}{x}
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Return the square root of \var{x}.
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\end{funcdesc}
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\begin{funcdesc}{tan}{x}
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Return the tangent of \var{x}.
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\end{funcdesc}
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\begin{funcdesc}{tanh}{x}
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Return the hyperbolic tangent of \var{x}.
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\end{funcdesc}
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Note that \function{frexp()} and \function{modf()} have a different
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call/return pattern than their C equivalents: they take a single
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argument and return a pair of values, rather than returning their
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second return value through an `output parameter' (there is no such
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thing in Python).
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The module also defines two mathematical constants:
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\begin{datadesc}{pi}
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The mathematical constant \emph{pi}.
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\end{datadesc}
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\begin{datadesc}{e}
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The mathematical constant \emph{e}.
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\end{datadesc}
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\begin{seealso}
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\seemodule{cmath}{Complex number versions of many of these functions.}
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\end{seealso}
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