Hazard and cumulative hazard functions for distributions which are built into flexsurv, and whose distribution functions are in base R.

## Usage

```
hexp(x, rate = 1, log = FALSE)
Hexp(x, rate = 1, log = FALSE)
hgamma(x, shape, rate = 1, log = FALSE)
Hgamma(x, shape, rate = 1, log = FALSE)
hlnorm(x, meanlog = 0, sdlog = 1, log = FALSE)
Hlnorm(x, meanlog = 0, sdlog = 1, log = FALSE)
hweibull(x, shape, scale = 1, log = FALSE)
Hweibull(x, shape, scale = 1, log = FALSE)
```

## Arguments

- x
Vector of quantiles

- rate
Rate parameter (exponential and gamma)

- log
Compute log hazard or log cumulative hazard

- shape
Shape parameter (Weibull and gamma)

- meanlog
Mean on the log scale (log normal)

- sdlog
Standard deviation on the log scale (log normal)

- scale
Scale parameter (Weibull)

## Details

For the exponential and the Weibull these are available analytically, and so are programmed here in numerically stable and efficient forms.

For the gamma and log-normal, these are simply computed as minus the log of the survivor function (cumulative hazard) or the ratio of the density and survivor function (hazard), so are not expected to be robust to extreme values or quick to compute.