llikGamma function

log likelihood and derivatives for Gamma distribution

llikGamma(x, shape, rate, full = FALSE)

Arguments

• x: variable that is distributed by gamma distribution
• shape: this is the distribution's shape parameter. Must be positive.
• rate: this is the distribution's rate parameters. Must be positive.
• full: Add the data frame showing x, mean, sd as well as the fx and derivatives

Returns

data frame with fx for the log pdf value of with dProb

that has the derivatives with respect to the prob parameters at the observation time-point

Details

In an rxode2() model, you can use llikGamma() but you have to use the x and rate arguments. You can also get the derivative of shape or rate with llikGammaDshape() and llikGammaDrate().

Examples

llikGamma(1, 1, 10)

# You can use this in `rxode2` too:

et  <- et(seq(0.001, 1, length.out=10))
et$shape <- 1
et$rate <- 10
 
model <- function() {
  model({
    fx <- llikGamma(time, shape, rate)
    dShape<- llikGammaDshape(time, shape, rate)
    dRate <- llikGammaDrate(time, shape, rate)
  })
}

rxSolve(model, et)

Author(s)

Matthew L. Fidler