# Cauchy-class

From distr v2.6
by Peter Ruckdeschel

##### Class "Cauchy"

The Cauchy distribution with location $l$, by default $=0$, and scale $s$ , by default $=1$,has
density
$$f(x) = \frac{1}{\pi s}
\left( 1 + \left(\frac{x - l}{s}\right)^2 \right)^{-1}%
$$
for all $x$.
C.f. `rcauchy`

- Keywords
- distribution

##### Objects from the Class

Objects can be created by calls of the form `Cauchy(location, scale)`

.
This object is a Cauchy distribution.

##### Slots

`img`

- Object of class
`"Reals"`

: The domain of this distribution has got dimension 1 and the name "Real Space". `param`

- Object of class
`"CauchyParameter"`

: the parameter of this distribution (location and scale), declared at its instantiation `r`

- Object of class
`"function"`

: generates random numbers (calls function`rcauchy`

) `d`

- Object of class
`"function"`

: density function (calls function`dcauchy`

) `p`

- Object of class
`"function"`

: cumulative function (calls function`pcauchy`

) `q`

- Object of class
`"function"`

: inverse of the cumulative function (calls function`qcauchy`

) `.withArith`

- logical: used internally to issue warnings as to interpretation of arithmetics
`.withSim`

- logical: used internally to issue warnings as to accuracy
`.logExact`

- logical: used internally to flag the case where there are explicit formulae for the log version of density, cdf, and quantile function
`.lowerExact`

- logical: used internally to flag the case where there are explicit formulae for the lower tail version of cdf and quantile function
`Symmetry`

- object of class
`"DistributionSymmetry"`

; used internally to avoid unnecessary calculations.

##### Extends

Class `"AbscontDistribution"`

, directly.
Class `"UnivariateDistribution"`

, by class `"AbscontDistribution"`

.
Class `"Distribution"`

, by class `"AbscontDistribution"`

.

##### Is-Relations

By means of `setIs`

, R ``knows'' that a distribution object `obj`

of class `"Cauchy"`

with location 0 and scale 1 also is
a T distribution with parameters `df = 1, ncp = 0`

.

##### Methods

- initialize
`signature(.Object = "Cauchy")`

: initialize method- location
`signature(object = "Cauchy")`

: returns the slot`location`

of the parameter of the distribution- location<-
`signature(object = "Cauchy")`

: modifies the slot`location`

of the parameter of the distribution- scale
`signature(object = "Cauchy")`

: returns the slot`scale`

of the parameter of the distribution- scale<-
`signature(object = "Cauchy")`

: modifies the slot`scale`

of the parameter of the distribution- +
`signature(e1 = "Cauchy", e2 = "Cauchy")`

: For the Cauchy distribution the exact convolution formula is implemented thereby improving the general numerical approximation.- *
`signature(e1 = "Cauchy", e2 = "numeric")`

- +
`signature(e1 = "Cauchy", e2 = "numeric")`

: For the Cauchy location scale family we use its closedness under affine linear transformations.

##### See Also

`CauchyParameter-class`

`AbscontDistribution-class`

`Reals-class`

`rcauchy`

##### Examples

```
C <- Cauchy(location = 1, scale = 1) # C is a Cauchy distribution with location=1 and scale=1.
r(C)(1) # one random number generated from this distribution, e.g. 4.104603
d(C)(1) # Density of this distribution is 0.3183099 for x=1.
p(C)(1) # Probability that x<1 is 0.5.
q(C)(.1) # Probability that x<-2.077684 is 0.1.
location(C) # location of this distribution is 1.
location(C) <- 2 # location of this distribution is now 2.
is(C,"Td") # no
C0 <- Cauchy() # standard, i.e. location = 0, scale = 1
is(C0,"Td") # yes
as(C0,"Td")
```

*Documentation reproduced from package distr, version 2.6, License: LGPL-3*

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