Normal log-density (C backend)

The logarithm of the normal density, computed directly rather than as log(dnorm(x)), so it stays finite far into the tails where the density itself underflows to zero.

Usage

core_normal_logpdf(x, mean = 0, sd = 1)

Arguments

x

Numeric vector of quantiles.

mean

Distribution mean (length-1, default 0).

sd

Distribution standard deviation (length-1, default 1, > 0).

Value

A numeric vector the length of x. Equivalent to stats::dnorm(x, mean, sd, log = TRUE).

Examples

core_normal_logpdf(c(-1, 0, 1))
#> [1] -1.4189385 -0.9189385 -1.4189385

# Identical to stats::dnorm(log = TRUE).
all.equal(core_normal_logpdf(-2:2, 0.3, 1.7),
          stats::dnorm(-2:2, 0.3, 1.7, log = TRUE))
#> [1] TRUE

# Still finite where the density itself underflows to zero.
stats::dnorm(50)                  # 0
#> [1] 0
core_normal_logpdf(50)            # about -1251
#> [1] -1250.919