Fit a Bulletin 17C (log-Pearson Type III) flood-frequency model by the generalized method of
moments and return the Cohn-style delta-method confidence intervals, the fitted parameters, and
the sandwich covariance. Wraps the shared C++ Bulletin17CAnalysis.
Usage
bulletin17c_analysis(
data,
uncertainty_method = "MultivariateNormal",
output_length = 10000L,
seed = 12345L,
confidence_level = 0.9,
exceedance_probabilities = NULL
)Arguments
- data
numeric vector of annual peak observations.
- uncertainty_method
uncertainty-quantification method:
"MultivariateNormal"(default),"Bootstrap","LinkedMultivariateNormal", or"BiasCorrectedBootstrap".- output_length
number of parameter-set draws used for uncertainty quantification.
- seed
PRNG seed for the uncertainty draw.
- confidence_level
confidence level for the intervals (e.g.
0.90).- exceedance_probabilities
optional numeric vector of exceedance probabilities; when
NULL, the 25 standard default ordinates are used.
Value
A named list: exceedance_probabilities, point_estimates (log10 space), lower_ci,
upper_ci (discharge space), confidence_level, beta1, nu, quantile_variance,
parameters (fitted location/scale/shape), and covariance (the p x p sandwich covariance).
Examples
peaks <- c(12500, 15300, 8900, 22100, 18700, 14200, 9800, 28500, 17400, 11600,
19200, 13800, 25600, 10500, 16900)
ci <- bulletin17c_analysis(peaks, output_length = 200, seed = 12345)
ci$confidence_level
#> [1] 0.9