Discrete {e1071} | R Documentation |
These functions provide information about the discrete distribution
where the probability of the elements of values
is proportional
to the values given in probs
, which are normalized to sum up to
1. ddiscrete
gives the density, pdiscrete
gives the
distribution function, qdiscrete
gives the quantile function
and rdiscrete
generates random deviates.
ddiscrete(x, probs, values = 1:length(probs)) pdiscrete(q, probs, values = 1:length(probs)) qdiscrete(p, probs, values = 1:length(probs)) rdiscrete(n, probs, values = 1:length(probs), method = "inverse", aliasmatrix = NULL) aliasmat(p) aliasmat2prob(aliasmatrix)
x,q |
vector or array of quantiles. |
p |
vector or array of probabilites. |
n |
number of observations. |
probs |
probabilities of the distribution. |
values |
values of the distribution. |
method |
generation method, can be "inverse" or
"alias" . |
aliasmatrix |
matrix needed by alias method. |
For the generation of the random deviates, one can choose between the
method "inverse"
which basically makes a lookup in the vector
of the probabilities and the method "alias"
. The latter method
computes an aliasmatrix by the function aliasmat
which allows a
faster data generation once this matrix is computed. If such a matrix
has already been computed, it can be passed as further argument to
rdiscrete
. aliasmat2prob
computed probabilities from a
given aliasmatrix
.
Andreas Weingessel and Friedrich Leisch
## a vector of length 30 whose elements are 1 with probability 0.2 ## and 2 with probability 0.8. rdiscrete (30, c(0.2, 0.8)) ## a vector of length 100 whose elements are A, B, C, D. ## The probabilities of the four values have the relation 1:2:3:3 rdiscrete (100, c(1,2,3,3), c("A","B","C","D"))