erf {VGAM} | R Documentation

## Error Function

### Description

Computes the error function based on the normal distribution.

### Usage

    erf(x)

### Arguments

`x` | Numeric.

### Details

Erf(x) is defined as

Erf(x) = (2/sqrt(pi)) int_0^x exp(-t^2) dt

so that it is closely related to `pnorm`.

### Value

Returns the value of the function evaluated at `x`.

### Note

Some authors omit the term 2/sqrt(pi) from the definition of Erf(x). Although defined for complex arguments, this function only works for real arguments.

The complementary error function erfc(x) is defined as 1-erf(x), and is implemented by `erfc`.

### Author(s)

T. W. Yee

### References

Abramowitz, M. and Stegun, I. A. (1972) Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables, New York: Dover Publications Inc.

### See Also

`pnorm`.

### Examples

    ## Not run:
    x = seq(-3, 3, len=200)
    plot(x, erf(x), type="l", col="red", las=1, lwd=2,
         main="red is erf(x), blue is pnorm(x)")
    abline(v=0, h=0, lty="dashed", col="black")
    lines(x, pnorm(x), col="blue", lty="dotted", lwd=2)
    ## End(Not run)

[Package VGAM version 0.7-9 Index]