Description Usage Arguments Details Value Note Author(s) See Also Examples
View source: R/UtilitiesDistributions.R
function to do get empirical density, cumulative distribution and quantile function from random numbers
1 2  RtoDPQ(r, e = getdistrOption("RtoDPQ.e"),
n = getdistrOption("DefaultNrGridPoints"), y = NULL)

r 
the random number generator 
e 
10^e numbers are generated, a higher number leads to a better result. 
n 
The number of grid points used to create the approximated functions, a higher number leads to a better result. 
y 
a (numeric) vector or 
RtoDPQ generates 10^e random numbers, by default
e = RtoDPQ.e
.
Instead of using simulated grid points, we have an optional parameter y
for using N. Horbenko's quantile trick: i.e.; on an equally spaced grid x.grid
on [0,1], apply
f(q(x)(x.grid))
and write the result to y
and produce density and cdf from this
value y
given to RtoDPQ
as argument (instead of simulating grid points).
The density is formed on the basis of n points using approxfun and density, by default
n = DefaultNrGridPoints
.
The cumulative distribution function and the quantile function are also created on the basis of n points using
approxfun
and ecdf
. Of course, the results are usually not exact as they rely on random numbers.
RtoDPQ
returns a list of functions.
dfun 
density 
pfun 
cumulative distribution function 
qfun 
quantile function 
Use RtoDPQ
for absolutely continuous and RtoDPQ.d
for discrete distributions.
Thomas Stabla [email protected],
Florian Camphausen [email protected],
Peter Ruckdeschel [email protected],
Matthias Kohl [email protected]
UnivariateDistributionclass
,
density
,
approxfun
,
ecdf
1 2 3 4 5 6 7 8 9 10 11  rn2 < function(n){rnorm(n)^2}
x < RtoDPQ(r = rn2, e = 4, n = 512)
# returns density, cumulative distribution and quantile function of
# squared standard normal distribution
x$dfun(4)
RtoDPQ(r = rn2, e = 5, n = 1024) # for a better result
rp2 < function(n){rpois(n, lambda = 1)^2}
x < RtoDPQ.d(r = rp2, e = 5)
# returns density, cumulative distribution and quantile function of
# squared Poisson distribution with parameter lambda=1

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