search for: inflexion

Buenas, ¿Cómo calculariais el punto de inflexion de esta curva marcado en rojo? [X] He probado de la siguiente manera: 1- Haciendo la segunda derivada:No me sirve, porque m edetecta muchas veces esos casos 2- Mirando si el siguiente valor es mayor que el anterior. No me vale, ya que si hay ruido, no lo va a detectar. 3. Mirando que el punto...

...able at a time from the most to the least important (not-too-correlated) variables. I then plot the error rate (err.rate) as a function of the number of variable used. As this number increase, the error first sharply decrease, but relatively soon it reaches a plateau . I assume that the point of inflexion can be use to derive the minimum number of variable to be used. Is that a sensible approach? Is there any other suggestion? A measure of the error on "err.rate" would also here really help. Is there any idea how to estimate this? From the variation between runs or with the help of &qu...

...noise > lines(y.spl, col="red") > I wish to obtain the zeros of the first and second derivatives of the smoothed spline y.spl. I can use uniroot() or optim() to find one root, but I cannot find a reliable way to iterate and find the desired number of solutions (3 peaks and 2 inflexion points on each side of them). I've used locator() or a guesstimate of the disjoints intervals to look for solutions, but I would like to get rid off this unnecessary user input and have a robust way of finding a predefined number of solutions in the total interval. Something along the l...

...algaard BSA <p.dalgaard at biostat.ku.dk> writes: > > > I think Occam/Ockham himself wrote in Latin. By my failing memory, the > > quote is > > > > "Entia non runt multiplicanda praeter necessitam" > > > > give or take a couple of incorrect inflexions. I.e. "Entities should > > not multiply unless necessary" -- do not invent more elaborate > > explanations than what is necessary to explain the facts. > > A little web search gave the following at > http://www2.jonction.net/~ziem/occam.html > > "Plural...