plausibility_contour: generate plausibility contour
In mhuiying/scp: Spatial Conformal Prediction

plausibility_contour

R Documentation

generate plausibility contour

Description

This function provides the plausibility contour for Y(s0), given observations s and Y, using spatial conformal prediction algorithms.

Usage

plausibility_contour(
  s0,
  s,
  Y,
  global = TRUE,
  eta = Inf,
  m = NULL,
  pred_fun = krige_pred,
  thetaHat = NULL,
  dfun = c("residual2", "std_residual2"),
  precision = NULL
)

Arguments

`s0`	prediction location, a numeric vector with `length = 2` or a `matrix` with 1 row and 2 cols, or a data.frame with 1 row and 2 cordinates.
`s`	an n x 2 `matrix` or a `data.frame` with two coordinates of n locations.
`Y`	a vector with n values corresponding to `Y(s)`.
`global`	logical; if `TRUE` , `scp` function returns the result of global spatial conformal prediction (GSCP); if `FALSE`, `scp` function returns the result of local spatial conformal prediction (LSCP) and users need to specify `eta < Inf` or `m` ≤ `n`. Defaults to `TRUE`.
`eta`	kernel bandwidth for weight schema, a positve scalar with smaller value meaning more localized procedure. Defauls to `Inf`, which puts equal weight on surrounding `m` points.
`m`	an postive integer representing the number of nearest locations to use for prediction. Default to `NULL`. If `global = TRUE`, `m = n`; if `global = FALSE` and `m` is not specified, `m` would be determined by `eta`.
`pred_fun`	spatial prediction function with inputs being `s0, s, Y` and ouputs being predicted `Y(s0)` (and its standard error). Defaults to `krige_pred`.
`thetaHat`	a vector of Matern parameters, representing nugget, partial sill, range, and smoothness as in Mao. et al. (2020). Defaults to `NULL`. It will be ignored if `pred_fun` is not `krige_pred`.
`dfun`	non-conformity measure with four options. In which, `"residual2"` (default) represents squared residual and `"std_residual2"` represents standardized squared residual.
`precision`	a positive scalar represents how dense `Y(s)` candidates (`Y_cand`) are. Defaults to `NULL`.

Value

The output is a “plausibility_contour” object.

Author(s)

Huiying Mao, hmao@samsi.info, Brian Reich bjreich@ncsu.edu

References

to be entered

Examples

## generate plausibility contour for Y(s0), where s0 = c(0.5,0.5), using sample data

#?sample_data
s0 = c(0.5,0.5)
s  = sample_data$s
Y  = sample_data$Y

pc = plausibility_contour(s0=s0,s=s,Y=Y)
plot(pc)

idx = which(s[, 1] == s0[1] & s[, 2] == s0[2])
abline(v = Y[idx], col = "red", lty = 2)
legend("topright", col=1:2, lty=1:2, c("plausibility", "true value"))

mhuiying/scp documentation built on May 4, 2022, 11:35 p.m.