Description Usage Arguments Details Examples
Calculates the variance of continuous, discrete and multivariate phase-type
distributions, represented by the cont_phase_type
,
disc_phase_type
and mult_cont_phase_type
classes respectively.
1 2 3 4 5 6 7 8 9 10 11 12 13 |
obj |
a |
... |
other arguments passed to methods |
v |
NULL, integer or vector of length 2. |
For the univariate case (cont_phase_type
and disc_phase_type
),
the variance of the distribution is returned.
In the case of multivariate phase-type distributions three different usages can be distinguished:
If v = NULL
(default), then a variance-covariance matrix of all
the variables specified in the reward matrix are returned, where variances
are in the diagonal and covariances in the rest of the matrix element.
If v
is an integer, then the variance of the variable encoded
by the v
index in the reward matrix is returned.
If v
is a vector of length 2, then the covariance between the
two variables encoded by the v
indices in the reward matrix is
returned.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | # For univariate continuous phase-type distributions
ph1 <- PH(matrix(c(-3, 0, 0, 1, -2, 0, 0, 1, -1), ncol = 3), c(0.25,0.25,0.5))
var(ph1)
# For multivariate continuous phase-type distributions
subintensity_matrix <- matrix(c(-3, 0, 0,
2, -2, 0,
0, 1, -1), nrow = 3, ncol = 3)
reward_matrix = matrix(sample(seq(0, 10), 6), nrow = 3, ncol = 2)
ph2 <- MPH(subintensity_matrix, reward_mat = reward_matrix)
## Variance-covariance matrix
var(ph2)
## Variance for the first state in the reward matrix
var(ph2, 1)
## Variance for the second state in the reward matrix
var(ph2, 2)
|
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