cocoPredict: Prediction for coco objects

In cocons: Covariate-Based Covariance Functions for Nonstationary Spatial Modeling

Prediction for coco objects

Description

Computes the conditional expectation and standard errors based on the conditional Gaussian distribution for nonstationary spatial models.

Usage

cocoPredict(coco.object, newdataset, newlocs, type = 'mean', ...)

Arguments

coco.object	(S4) A fitted coco object.
newdataset	(data.frame) A data.frame containing the covariates present in model.list at the prediction locations.
newlocs	(matrix) A matrix specifying the prediction locations, matching newdataset index.
type	(character) Specifies whether to return only the point prediction ('mean') or both the point prediction and prediction standard errors ('pred').
...	Additional arguments. If coco.object contains multiple realizations, the argument index.pred can be used to specify which realization of coco.object@z should be used for predictions.

Value

A list containing:

• systematic: The systematic component of the conditional expectation.

• stochastic: The stochastic component of the conditional expectation.

• sd.pred: The standard errors, when type = 'pred' is specified.

Author(s)

Federico Blasi

Examples

## Not run: 

# Stationary model

model.list_stat <- list('mean' = 0,
'std.dev' = formula( ~ 1),
'scale' = formula( ~ 1),
'aniso' = 0,
'tilt' = 0,
'smooth' = 3/2,
'nugget' = -Inf)

 
model.list_ns <- list('mean' = 0,
'std.dev' = formula( ~ 1 + cov_x + cov_y),
'scale' = formula( ~ 1 + cov_x + cov_y),
'aniso' = 0,
'tilt' = 0,
'smooth' = 3/2,
'nugget' = -Inf)

coco_object <- coco(type = 'dense',
data = holes[[1]][1:100, ],
locs = as.matrix(holes[[1]][1:100, 1:2]),
z = holes[[1]][1:100, ]$z,
model.list = model.list_stat)

optim_coco_stat <- cocoOptim(coco_object,
boundaries = getBoundaries(coco_object,
lower.value = -3, 3))

coco_preds_stat <- cocoPredict(optim_coco_stat, newdataset = holes[[2]],
newlocs = as.matrix(holes[[2]][, 1:2]),
type = "pred")

# Update model
[e-mail] <- model.list_ns

optim_coco_ns <- cocoOptim(coco_object,
boundaries = getBoundaries(coco_object,
lower.value = -3, 3))

coco_preds_ns <- cocoPredict(optim_coco_ns, newdataset = holes[[2]],
newlocs = as.matrix(holes[[2]][, 1:2]),
type = "pred")

par(mfrow = c(1, 3))

fields::quilt.plot(main = "full data", holes[[1]][, 1:2], 
holes[[1]]$z, xlim = c(-1, 1), ylim = c(-1, 1))

fields::quilt.plot(main = "stationary se", holes[[2]][, 1:2], 
coco_preds_stat$sd.pred, xlim = c(-1, 1), ylim = c(-1, 1))
fields::quilt.plot(main = "nonstationary se", holes[[2]][, 1:2], 
coco_preds_ns$sd.pred, xlim = c(-1, 1), ylim = c(-1, 1))



## End(Not run)

cocons documentation built on April 4, 2025, 3:21 a.m.