erf {VGAM} | R Documentation |
Computes the error function based on the normal distribution.
erf(x)
x |
Numeric. |
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
.
Returns the value of the function evaluated at x
.
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
.
T. W. Yee
Abramowitz, M. and Stegun, I. A. (1972) Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables, New York: Dover Publications Inc.
## 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)