secant {DFA} | R Documentation |
Applies the secant method for detection of crossover points on the log-log curve.
secant(x,y,npoint,size_fit)
x |
Vector of the decimal logarithm of the boxes sizes. |
y |
Vector of the decimal logarithm of the DFA calculated in each boxe. |
npoint |
Number of crossover points calculated on the log-log curve. |
size_fit |
Number of points of the two semi-curved fitted in the extremes of the log-log curve. |
position |
Position of the crossover point identified by the secant method. |
Victor Barreto Mesquita
# Example with the data referring to the log fluctuation
#channel curve data calculated for an epileptic subject
#extracted in the Physionet platform.
library(DFA)
data("EEGsignal")
x<-EEGsignal$`log10(boxes)`
y<-EEGsignal$`log10(DFA)`
plot(x,y,xlab="log10(boxes)",ylab="log10(DFA)")
secant(x,y,npoint=2,size_fit=8)
# Example with crossover point fixed in position=20.
library(DFA)
part1 <- seq(1,20)
part2 <- seq(20,1)
y = c(part1,part2)
x<-seq(1,40)
plot(x,y)
secant(x,y,npoint=1,size_fit=8)