derivatives {irtProb} | R Documentation |
Three points first and second derivatives numerical approximation used with the m4plEstimateMore
function.
fprime( x, FUN = "FP", h = 0.001, names = paste("x", c(1:length(x)), sep = "")) fsecond(x, FUN = "FP", h = 0.001, names = paste("x", c(1:length(x)), sep = ""))
x |
numeric; vector of values at which the derivation is to be done. |
FUN |
function; function to derive. |
h |
numeric; neighbouring value. |
names |
character; names given to each results. DEFAULT to the existing names of the vector x. |
This function could be used for numerical derivation in general, but is dedicated to be used internally by m4plEstimateMore
.
For other general purposes D
, deriv
and deriv3
are preferred.
fprime |
numeric; vector of first derivatives. |
fsecond |
numeric; matrix of second derivatives. |
Gilles Raiche, Universite du Quebec a Montreal (UQAM),
Departement d'education et pedagogie
Raiche.Gilles@uqam.ca, http://www.er.uqam.ca/nobel/r17165/
Press, W. H., Vetterling, W. T., Teukolsky, S. A. and Flannery, B. P. (2002). Numerical recipees in C++. The art of scientific computing, 2nd edition. Cambridge, United Kingdom: Cambridge University press.
Yakowitz, S. and Szidarovszky, F. (1986). An introduction to numerical computations. New York, New Jersey: MacMilla.
## ..................................... test <- function(x) 2*x+5 test( x=0) fprime( x=0, FUN=test) fsecond(x=0, FUN=test) ## ..................................... test2 <- function(x) 2*(x[1]*x[2])+5 test2( x=c(0,0)) fprime( x=c(0,0), FUN=test2) fsecond(x=c(0,0), FUN=test2)