optim function

Function to calculate smoothness and squintability

sample_bases(
  idx,
  data = sine1000,
  n_basis = 300,
  parallel = FALSE,
  best = matrix(c(0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1), nrow = 6),
  min_proj_dist = NA,
  step_size = NA,
  seed = 123
)

## S3 method for class 'basis_df'
print(x, width = NULL, ...)

## S3 method for class 'basis_df'
tbl_sum(x)

calc_smoothness(
  basis_df,
  start_params = c(0.001, 0.5, 2, 2),
  other_gp_params = NULL,
  verbose = FALSE
)

## S3 method for class 'smoothness_res'
print(x, width = NULL, ...)

## S3 method for class 'smoothness_res'
tbl_sum(x)

calc_squintability(
  basis_df,
  method = c("ks", "nls"),
  scale = TRUE,
  bin_width = 0.005,
  other_params = NULL
)

## S3 method for class 'squintability_res'
print(x, width = NULL, ...)

## S3 method for class 'squintability_res'
tbl_sum(x)

fit_ks(basis_df, idx, other_params = NULL)

fit_nls(basis_df, other_params = NULL)

Arguments

• idx: character, the name of projection pursuit index function, e.g. "holes"
• data: a matrix or data frame, the high dimensional data to be projected
• n_basis: numeric, the number of random bases to generate
• parallel: logic, whether to use parallel computing for calculating the index. Recommend for the stringy index.
• best: a matrix, the theoretical/ empirical best projection matrix to calculate the projection distance from the simulated random bases.
• min_proj_dist: only for squintability, the threshold for projection distance for the random basis to be considered in sampling
• step_size: numeric, step size for interpolating from each random basis to the best basis, recommend 0.005
• seed: numeric, seed for sampling random bases
• x: objects with specialised printing methods
• width: only used when max.levels is NULL, see above.
• ...: further arguments passed to or from other methods.
• basis_df: the basis data frame returned from sample_bases
• start_params: list, the starting parameters for the Gaussian process for smoothness
• other_gp_params: list, additional parameters to be passed to [GpGp::fit_model()] for calculating smoothness
• verbose: logical, whether to print optimisation progression when fitting the Gaussian process
• method: either "ks" (kernel smoothing) or "nls" (non-linear least square) for calculating squintability.
• scale: logic, whether to scale the index value to 0-1 in squintability
• bin_width: numeric, the bin width to average the index value before fitting the kernel, recommend to set as the same as step parameter
• other_params: list additional parameters for fitting kernel smoothing or non-linear least square, see [stats::ksmooth()] and [stats::nls()] for details

Examples

## Not run:

library(GpGp)
library(fields)
library(tourr)
basis_smoothness <- sample_bases(idx = "holes")
calc_smoothness(basis_smoothness)
basis_squint <- sample_bases(idx = "holes", n_basis = 100, step_size = 0.01, min_proj_dist = 1.5)
calc_squintability(basis_squint, method = "ks", bin_width = 0.01)
## End(Not run)