Computes composites
Composites a 3-d field var(x, y, time) according to the indices of mode/cluster occurrences in time and computes the pvalues (t-test). x and y are typically lon and lat, but function can accept other 2-d fields such as lat and depth, lon and depth, etc.
Composite(var, occ, lag = 0, eno = FALSE, K = NULL, fileout = NULL)
var |
3-dimensional array (x, y, time) containing the variable to composite. |
occ |
1-dimensional array for the occurrence time series of mode(s)/cluster(s). (*1) When one wants to composite all modes, e.g., all K = 3 clusters then for example occurrences could look like: 1 1 2 3 2 3 1 3 3 2 3 2 2 3 2. (*2) Otherwise for compositing only the 2nd mode or cluster of the above example occurrences should look like 0 0 1 0 1 0 0 0 0 1 0 1 1 0 1. |
lag |
Lag time step (an integer), e.g., for lag = 2 composite will use +2 occurrences (i.e., shifted 2 time steps forward). Default is lag = 0. |
eno |
For using the effective sample size (TRUE) or the total sample size (FALSE that is the default) for the number of degrees of freedom. |
K |
numeric value indicating the maximum number of composites. By default (NULL), it takes the maximum value provided in occ. |
fileout |
Name of the .sav output file (NULL is the default). |
$composite |
3-d array (x, y, k) containing the composites k=1,..,K for case (*1) or only k=1 for any specific cluster, i.e., case (*2). |
$pvalue |
3-d array (x, y, k) containing the pvalue of the composites obtained through a t-test that accounts for the serial dependence of the data with the same structure as Composite. |
History: 0.1 # 2014-08 (N.S. Fuckar, neven.fuckar@bsc.es) # Original code
blank <- array(0, dim=c(20, 10, 30))
x1 <- blank
t1 <- blank
f1 <- blank
for (i in 1:20) {
x1[i,,] <- i
}
for (i in 1:30) {
t1[,,i] <- i
}
# This is 2D propagating sin wave example, where we use (x,y,t) structure of
# f1 wave field. Compositing (like using stroboscopicc light) at different time
# steps can lead to modification or cancelation of wave pattern.
for (i in 1:20) {
for (j in 1:30) {
f1[i,,j] <- 3*sin(2*pi*x1[i,,j]/5. - 2*pi*t1[i,,j]/6.)
}
}
occ1 <- rep(0, 30)
occ1[c(2, 5, 8, 11, 14, 17, 20, 23)] <- 1
filled.contour(Composite(var=f1, occ=occ1)$composite[,,1])
occ2 <- rep(0, 30)
occ2[c(3, 9, 15, 21)] <- 1
filled.contour(Composite(var=f1, occ=occ2)$composite[,,1])
# Example with one missing composite (#3) in occ:
data <- 1 : (4 * 5 * 6)
dim(data) <- c(lon = 4, lat = 5, case = 6)
occ <- c(1, 1, 2, 2, 3, 3)
res <- Composite(data, occ, K = 4)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.