Calculate the sum of squares feature or metric for a gray-level co-occurrence matrix. For definition and application, see Lofstedt et al. (2019) doi:10.1371/journal.pone.0212110 .
sum_squares(x, ...)
# S3 method for default
sum_squares(x, ...)
# S3 method for matrix
sum_squares(x, ...)
# S3 method for FitLandDF
sum_squares(x, nlevels, ...)gray-level co-occurrence matrix
additional parameters
desired number of discrete gray levels
sum of squares metric of x
## calculate sum of squares of arbitrary GLCM
# define arbitrary GLCM
x <- matrix(1:16, nrow = 4)
# normalize
n_x <- normalize_glcm(x)
# calculate sum of squares
sum_squares(n_x)
#> [1] 7.908318
## calculate sum of squares of arbitrary fitness landscape
# create fitness landscape using FitLandDF object
vals <- runif(64)
vals <- array(vals, dim = rep(4, 3))
my_landscape <- fitscape::FitLandDF(vals)
# calculate sum of squares of fitness landscape, assuming 2 discrete gray levels
sum_squares(my_landscape, nlevels = 2)
#> [1] 1.792175
## confirm value of sum of squares for fitness landscape
# extract normalized GLCM from fitness landscape
my_glcm <- get_comatrix(my_landscape, discrete = equal_discrete(2))
# calculate sum of squares of extracted GLCM
sum_squares(my_glcm) # should match value of above sum_squares function call
#> [1] 1.792175