optimize in very small values - uniroot solved it
Dear friends - just to prevent further loss of time on the problem below - I realized that it was really a root finding exercise and not a minimization - uniroot solved the problem. Sorry for the confusion. Best wishes Troels
At 00:06 11/23/04, you wrote:
I hope you will forgive me this simple question on titration.
I'm trying to find very small values from the algorithm below, which I
believe is
correctly formatted, and the constants are also correct. When SID goes
over ATOT, fitted vales are
much too low compared to the literature. I guess I must be using optimize
in a wrong way but cannot find out how to improve it. I'm on windows, R
2.0. Best wishes
Troels Ring, Aalborg
ATOT <- 0.019
KA <- 3e-7
KW <- 4.4e-14
SID <- 0.01
ff <- function(H,KA,SID,ATOT)
{H^3 + (KA+SID)*H^2+(KA*(SID-ATOT)-KW)*H- KA*KW}
-log10(optimize(ff,c(0,.1),tol=.Machine$double.eps,KA=KA,SID=SID,ATOT=ATOT)$minimum)
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