Function `log(2*P(x))' and its derivatives

Usage

zeta(k, x)

Arguments

k an integer scalar.
x a vector. Missing values (NaNs) are allowed, but Infs are not.

Description

The function log(2 P(x)) and its derivatives up to order 4, if P(x) denotes the standard normal distribution function.

Details

k denotes the order of the derivative. If k is 0, the function is evaluated, using normcdf(x) for x>-35, an asymptotic expansion otherwise. For k between 1 and 4, the derivative of that order is evaluated. For k>4, a warning message is issued, and a vector of NaNs is returned.

This function is used by sn_dev and msn_dev, among others.

Value

a vector; this is the k-th order derivative evaluated at x

See Also

sn_mle, msn_mle

Examples

y = zeta(2,[-20:0.5:20])


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