erf {VGAM} | R Documentation |
Computes the error function based on the normal distribution.
erf(x)
x |
Numeric. |
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: curve(erf, -3, 3, col="red", ylab="", las=1) curve(pnorm, -3, 3, add=TRUE, col="blue", lty="dotted", lwd=2) abline(v=0, h=0, lty="dashed") legend("topleft", c("erf(x)", "pnorm(x)"), col=c("red", "blue"), lty=c("solid", "dotted"), lwd=1:2) ## End(Not run)