Rice {VGAM} | R Documentation

## The Rice Distribution

### Description

Density, distribution function, quantile function and random generation for the Rician distribution.

### Usage

    drice(x, sigma, vee, log = FALSE)
    price(q, sigma, vee, lower.tail = TRUE, log.p = FALSE, ...)
    qrice(p, sigma, vee, lower.tail = TRUE, log.p = FALSE, ...)
    rrice(n, sigma, vee)

### Arguments

`x, q` | vector of quantiles.
`p` | vector of probabilities.
`n` | number of observations. Same as in `runif`.
`vee, sigma` | See `riceff`.
`...` | Other arguments such as `lower.tail`.
`lower.tail, log.p` | Same meaning as in `pnorm` or `qnorm`.
`log` | Logical. If `log = TRUE` then the logarithm of the density is returned.

### Details

See `riceff`, the VGAM family function for estimating the two parameters, for the formula of the probability density function and other details.

Formulas for `price()` and `qrice()` are based on the Marcum-Q function.

### Value

`drice` gives the density, `price` gives the distribution function, `qrice` gives the quantile function, and `rrice` generates random deviates.

### Author(s)

T. W. Yee and Kai Huang

### See Also

`riceff`.

### Examples

    ## Not run:  x <- seq(0.01, 7, len = 201)
    plot(x, drice(x, vee = 0, sigma = 1), type = "n", las = 1,, ylab = "",
         main = "Density of Rice distribution for various values of v")
    sigma <- 1; vee <- c(0, 0.5, 1, 2, 4)
    for (ii in 1:length(vee))
      lines(x, drice(x, vee = vee[ii], sigma), col = ii)
    legend(x = 5, y = 0.6, legend = as.character(vee),
           col = 1:length(vee), lty = 1)

    x <- seq(0, 4, by = 0.01); vee <- 1; sigma <- 1
    probs <- seq(0.05, 0.95, by = 0.05)
    plot(x, drice(x, vee = vee, sigma = sigma), type = "l", col = "blue",
         main = "Blue is density, orange is cumulative distribution function",
         ylim = c(0, 1), sub = "Purple are 5, 10, ..., 95 percentiles",
         las = 1, ylab = "", cex.main = 0.9)
    abline(h = 0:1, col = "black", lty = 2)
    Q <- qrice(probs, sigma, vee = vee)
    lines(Q, drice(qrice(probs, sigma, vee = vee),
                   sigma, vee = vee), col = "purple", lty = 3, type = "h")
    lines(x, price(x, sigma, vee = vee), type = "l", col = "orange")
    lines(Q, drice(Q, sigma, vee = vee), col = "purple", lty = 3, type = "h")
    lines(Q, price(Q, sigma, vee = vee), col = "purple", lty = 3, type = "h")
    abline(h = probs, col = "purple", lty = 3)
    max(abs(price(Q, sigma, vee = vee) - probs))  # Should be 0

    ## End(Not run)

[Package VGAM version 1.1-1 Index]