Package 'telefit'

Title: Estimation and Prediction for Remote Effects Spatial Process Models
Description: Implementation of the remote effects spatial process (RESP) model for teleconnection. The RESP model is a geostatistical model that allows a spatially-referenced variable (like average precipitation) to be influenced by covariates defined on a remote domain (like sea surface temperatures). The RESP model is introduced in Hewitt et al. (2018) <doi:10.1002/env.2523>. Sample code for working with the RESP model is available at <https://jmhewitt.github.io/research/resp_example>. This material is based upon work supported by the National Science Foundation under grant number AGS 1419558. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.
Authors: Joshua Hewitt
Maintainer: Joshua Hewitt <[email protected]>
License: GPL-3
Version: 1.0.3
Built: 2024-11-08 06:46:39 UTC
Source: CRAN

Help Index


Convenience function for stacking matrices into an array.

Description

This function extends the abind function from the abind package.

Usage

abind3(...)

Arguments

...

Any number of matrices of equal dimension to stack together into a 3d matrix


Reshape array of data matrices into long format

Description

Reshape array of data matrices into long format

Usage

arrayToLong(X, coords, yrs)

Arguments

X

3 dimensional array of matrices to extract to long format

coords

Spatial coordinates associated with the data (longitude in first column)

yrs

Vector with labels for the years


Make predictions using canonical correlation analysis (CCA)

Description

Canonical correlation analysis (CCA) is sometimes referred to as a double-barreled principal component analysis. Loosely, it fits a linear regression model to the scores of principal component decompositions for of the predictors X and responses Y. Oftentimes, only the largest kk principal components are used to make predictions.

Usage

cca.predict(X, Y, X.new, k.x, k.y)

Arguments

X

An (nvars x nobs) data frame or matrix in which each column contains all observations of measured (predictor) variables for a given timepoint or sample. For example, if X represents a spatial variable that was recorded at several timepoints, then each row of X should contain the variable's measurement for all timepoints at a single location.

Y

An (nvars x nobs) data frame or matrix in which each column contains all observations of measured (response) variables for a given timepoint or sample.

X.new

An (nvars x nobs.new) data frame or matrix of values to use to predict Y.new using CCA.

k.x

An integer less than (nobs) indicating how many eigenvectors of (X) to use in the CCA.

k.y

An integer less than (nobs) indicating how many eigenvectors of (Y) to use in the CCA.

Details

CCA has been used to predict a teleconnected response (like precipitation) using the remote field generating the teleconnection (like ocean temperatures). In this application, principal components are often referred to as empirical orthogonal functions (EOFs).

Value

Y.new Predicted values for Y.new

References

Cook, E.R., Briffa, K.R., and Jones, P.D., 1994, Spatial regression methods in dendroclimatology: A review and comparison of two techniques: International Journal of Climatology, v. 14, p. 379-402.

Glahn, H.R., 1968, Canonical Correlation and Its Relationship to Discriminant Analysis and Multiple Regression: Journal of the Atmospheric Sciences, v. 25, p. 23-31.

Examples

data("coprecip")
attach(coprecip)

# compute CCA predictions of Y (CO precipitation) given Z (Pacific ocean SSTs)
# using 2 principal components (aka. EOFs)
preds = cca.predict(X = Z, Y = Y, X.new = Z, k.x = 2, k.y = 2)

# compute R^2
1 - var(as.numeric(preds-Y)) / var(as.numeric(Y))

Compute point estimates for parameters from posterior samples

Description

Compute point estimates for parameters from posterior samples

Usage

## S3 method for class 'stFit'
coef(object, burn = 1, fun = mean, ...)

Arguments

object

stFit object containing posterior samples for model

burn

number of posterior samples to reject before computing estimates

fun

function for computing point estimates

...

S3 generic/method consistency

Examples

data("coprecip.fit")
coef(coprecip.fit, burn = 50)

Compute point estimates for parameters from posterior samples

Description

Compute point estimates for parameters from posterior samples

Usage

## S3 method for class 'stPredict'
coef(object, stFit, stData, burn = 1, type = "eof-alpha_knots", ...)

Arguments

object

stPredict object containing posterior estimates of alphas

stFit

stFit object containing posterior samples for model

stData

stData object containing spatial information for dataset

burn

number of posterior samples to reject before computing estimates

type

One of the following options to specify what point estimates to return

eof-alpha_knots

Remote coefficient estimates (alpha_knots) mapped onto the eof patterns of the remote covariates.

...

S3 generic/method consistency

Examples

data("coprecip")
data("coprecip.fit")
data("coprecip.predict")

coef(coprecip.predict, stFit = coprecip.fit, stData = coprecip, burn = 50)

Standardized anomalies of CO Precipitation

Description

A dataset containing sample spatially-aggregated climate data from the ERA-Interim and PRISM datasets. The response comes from PRISM, average monthly precipitation in a DJF winter. The covariates come from ERA-Interim, Colorado and Pacific Ocean (sea) surface temperatures. All data has been converted to standardized anomalies.

Usage

coprecip

Format

A stData object with 3 years of observations

tLabs

year labels for data columns

coords.s

centers of grid cells for Colorado data

coords.r

centers of grid cells for Pacific Ocean data

X

Array of design matrices for Colorado covariates

Y

Matrix of precipitation observations

Z

Matrix of Pacific Ocean data

X.lab

Label for covariate data, used by plotting functions

Y.lab

Label for response data, used by plotting functions

Z.lab

Label for covariate data, used by plotting functions

Source

http://prism.oregonstate.edu

https://rda.ucar.edu/datasets/ds627.0/

Examples

data("coprecip")
str(coprecip)

Sample MCMC output for the RESP model

Description

An example stFit object containing output from a short run of the MCMC sampler that fits the RESP model to data.

Usage

coprecip.fit

Format

An stFit object, which is a list of several objects

parameters

MCMC samples of model parameters

priors

description of priors used to fit model

miles

TRUE or FALSE to specify whether the spatial distances used to estimate spatial covariance parameters were in units of miles (TRUE) or kilometers (FALSE)

localOnly

TRUE if remote covariates were not estimated

remoteOnly

TRUE if local covariates were not estimated

varying

(deprecated) TRUE if local covariates were estimated as a spatially-varying field

coords.knots

coordinates of remote knot locations

Examples

data("coprecip.fit")
str(coprecip.fit)

Sample composition sampling output for the RESP model

Description

An example stPredict object containing predictions from a short run of the MCMC composition sampler. The output also contains teleconnection estimates.

Usage

coprecip.predict

Format

An stPredict object, which is a list of several objects

pred

A list containing summaries of posterior predictions

samples

Posterior samples for predictions

coords.s

centers of grid cells for Colorado data

localOnly

TRUE if remote covariates were not estimated

varying

(deprecated) TRUE if local covariates were estimated as a spatially-varying field

tLabs

year labels for prediction timepoints

Y.lab

Label for response data, used by plotting functions

cat.probs

vector of probabilities for using posterior samples to return categorical predictions from the posterior prediction samples

category.breaks

Breakpoints used to discretize posterior predictive distribution at each coordinate in coords.s during composition sampling.

alpha_knots

Summaries of posterior estimates of teleconnection effects

eof_alpha_knots

Summaries of posterior estimates of teleconnection effects after spatial basis function transformation

Examples

data("coprecip.predict")
str(coprecip.predict)

Evaluate kron(A,B) * C without storing kron(A,B)

Description

Evaluate kron(A,B) * C without storing kron(A,B)

Usage

dgemkmm(A, B, C)

Arguments

A

(m x n) matrix

B

(p x q) matrix

C

(nq x r) matrix


Performs an EOF decomposition of the data

Description

Uses the stats::prcomp function to implement EOF decompositions of data

Usage

eof(X, center = F, scale = F)

Arguments

X

[variable x observation] matrix of data for which to compute EOFs

center

TRUE/FALSE to center columns of X in call to prcomp

scale

TRUE/FALSE to scale columns of X in call to prcomp

Value

A list containing EOF patterns as columns, and their scores

Examples

data("coprecip")
attach(coprecip)

# compute ocean surface temperature eofs
eofs = eof(Z)

# view first EOF, which corresponds to the El-Nino pattern
coords.r.mod = coords.r
coords.r.mod[,1][coords.r.mod[,1]>0] =
  coords.r.mod[,1][coords.r.mod[,1]>0] - 360
fields::quilt.plot(coords.r.mod, eofs$patterns[,1])

# alternatively, the plot.stData function can directly compute and plot EOFs
plot(coprecip, type='eof', pattern=1)

Wrapper for a function to dump errors from C++

Description

Wrapper for a function to dump errors from C++

Usage

errDump(x, fname = file.path(tempdir(), "error_samplerState.RData"))

Arguments

x

Data to save

fname

Path/name to save data to


Extract region from a SpatialGridDataFrame

Description

This method is intended for use as the main helper function for extractStData.

Usage

extractRegion(
  sgdf,
  extent,
  type = "response",
  aggfact = NULL,
  mask = NULL,
  aspect = F,
  aspect.categories = NULL,
  slope = F
)

Arguments

sgdf

SpatialGridDataFrame containing data to extract

extent

raster::extent object featuring region to extract, or a SpatialPolygonsXXX object used for extracting areal data

type

whether to return the raw data, anomalies (data minus temporal average at each location), standardized anomalies (anomalies divided by temporal standard deviation at each location), or spatially standardized data (data minus overall spatial average divided by spatial std. dev.; each year gets its own spatial standardization )

aggfact

if provided, will spatially average the data

mask

if an sgdf is provided, the data will be masked before extraction, aggregation, and anomaly computation

aspect

TRUE to return the aspect of the surface at each location instead of the value of the surface itself

aspect.categories

if aspect==TRUE, this specifies the number of discrete categories to divide aspect numbers (0-360) into. NULL if the original scale (0-360) should be kept. By design, the aspect categories will be centered on north in the first category.

slope

TRUE to return the slope of the surface at each location instead of the value of the surface itself

Value

a modified SpatialGridDataFrame, sgdf, with the climatology for each location accessible via attr(sgdf@data@values, 'scaled:center') if anomalies were computed


Basic extraction of SpatialGridDataFrame data for teleconnection analysis

Description

Basic extraction of SpatialGridDataFrame data for teleconnection analysis

Usage

extractStData(
  X,
  Y,
  Z,
  t = NULL,
  D.s,
  D.r,
  mask.s = NULL,
  mask.r = NULL,
  aggfact.s = NULL,
  aggfact.r = NULL,
  intercept = T,
  type.s = "response",
  type.r = "response",
  type.s.y = "response",
  X.lab = NULL,
  Y.lab = NULL,
  Z.lab = NULL,
  aspect = F,
  aspect.categories = 4,
  slope = F,
  colnames.X = NULL,
  formula = NULL
)

Arguments

X

SpatialGridDataFrame with local covariates. If X is a list, each SpatialGridDataFrame will be included as one covariate.

Y

SpatialGridDataFrame with response data

Z

SpatialGridDataFrame with remote covariates. If Z is a list, this function assumes each element of the list contains observations for the same covariate, but from different spatial regions. If Z is a list, D.r and mask.r must also be lists so that this function can know which regions to extract from each SpatialGridDataFrame

t

Timepoint from which to extract data from X, Y, and Z. If NULL, then all timepoints will be used.

D.s

c(xmin, xmax, ymin, ymax) region from which to extract data from X and Y, or a SpatialPolygonsXXX object containing boundaries of regions to extract areal data from.

D.r

c(xmin, xmax, ymin, ymax) region from which to extract data from Z

mask.s

SpatialGridDataFrame to be used as a mask when extracting data from X and Y. Locations in mask.s with NA values will be ignored when extracting data from X and Y.

mask.r

SpatialGridDataFrame to be used as a mask when extracting data from Z. Locations in mask.s with NA values will be ignored when extracting data from Z.

aggfact.s

If provided, will spatially average Y and X data

aggfact.r

If provided, will spatially average Z data

intercept

If TRUE, an intercept will be added to the design matrix

type.s

'response' 'anomaly' or 'std.anomaly' or a vector of these options depending on whether data extracted from X should be the observed data, anomalies, or standardized anomalies (where the climatology is computed from the observations as the pointwise temporal average)

type.r

'response' 'anomaly' or 'std.anomaly' or a vector of these options depending on whether data extracted from Z should be the observed data, anomalies, or standardized anomalies (where the climatology is computed from the observations as the pointwise temporal average)

type.s.y

'response' 'anomaly' or 'std.anomaly' depending on whether data extracted from Y should be the observed data, anomalies, or standardized anomalies (where the climatology is computed from the observations as the pointwise temporal average)

X.lab

name for X data (optional)

Y.lab

name for Y data (optional)

Z.lab

name for Z data (optional)

aspect

TRUE or vector of logicals (one for each X object) to return the aspect of the surface at each location instead of the value of the surface itself

aspect.categories

if aspect==TRUE, this specifies the number of discrete categories to divide aspect numbers (0-360) into. NULL if the original scale (0-360) should be kept. By design, the aspect categories will be centered on north in the first category.

slope

TRUE or vector of logicals (one for each X object) to return the slope of the surface at each location instead of the value of the surface itself

colnames.X

names of columns of X

formula

formula object to specify how to create the design matrix

Examples

# the extractRegion and extractStData methods create data matrices from 
# SpatialGridDataFrame objects

library(sp)

data("coprecip")
attach(coprecip)


#
# build SpatialGridDataFrame objects containing some of the coprecip data
#

gt = GridTopology(cellcentre.offset = apply(coords.s, 2, min),
                  cellsize = c(.5, .5), 
                  cells.dim = c(20, 12))

# Note: This is an example only; this grid will not match coprecip$coords.r
gt.Z = GridTopology(cellcentre.offset = apply(coords.r, 2, min),
                    cellsize = c(1.4, 1.4),
                    cells.dim = c(101, 52))

Xd = data.frame(`1981` = X[,2,1], `1982` = X[,2,2])
colnames(Xd) = gsub('X','', colnames(Xd))
sgdf.x = SpatialGridDataFrame(gt, Xd)


Yd = data.frame(`1981` = Y[,1], `1982` = Y[,2])
colnames(Yd) = gsub('X','', colnames(Yd))
sgdf.y = SpatialGridDataFrame(gt, Yd)


Zd = data.frame(`1981` = Z[,1], `1982` = Z[,2])
colnames(Zd) = gsub('X','', colnames(Zd))
sgdf.z = SpatialGridDataFrame(gt.Z, Zd)

# only extract a region of the coordinates
coprecip2 = extractStData(sgdf.x, sgdf.y, sgdf.z, 
                    D.s = c(-105, -103, 37, 41),
                    D.r = c(-160, -100, -15, 0))

Solves a triangular system with a Kronecker product structure

Description

Solves kron(A,B)x=ykron(A, B) x = y where AA and BB are lower triangular matrices.

Usage

forwardsolve.kron(A, B, y)

Arguments

A

an mxnm x n matrix

B

an pxqp x q matrix

y

an mpxsmp x s matrix

Value

x

Examples

set.seed(2018)

coord.s = matrix(runif(100), ncol=2)
coord.r = matrix(runif(50), ncol=2)

d.s = as.matrix(dist(coord.s))
d.r = as.matrix(dist(coord.r))

S1 = exp(-d.s)
S2 = exp(-d.r)

A = t(chol(S1))
B = t(chol(S2))

s = 15
  
x = matrix(runif(nrow(S1)*nrow(S2)*s), ncol=s)

y = kronecker(A,B) %*% x

x.solved = forwardsolve.kron(A, B, y)

max(abs(x - x.solved))

Compute Highest posterior density intervals from posterior samples

Description

Compute Highest posterior density intervals from posterior samples

Usage

## S3 method for class 'stFit'
HPDinterval(stFit, burn = 1, prob = 0.95)

Arguments

stFit

stFit object containing posterior samples for model

burn

number of posterior samples to reject before computing estimates

prob

The target probability content of the intervals

Examples

data("coprecip.fit")
HPDinterval.stFit(coprecip.fit, burn = 50)

Samples an Inverse-Wishart matrix

Description

Samples W IW(Psi,n)W ~ IW(Psi, n)

Usage

invWSamp(Psi, n)

Arguments

Psi

an nxnn x n scale matrix

n

degrees of freedom parameter

Examples

A = matrix(c(1,.5,.5,1), ncol=2)
W = invWSamp(A, 3)

Samples a multivariate normal with a Kronecker product covariance structure

Description

Samples x N(0,AxB)x ~ N(0, AxB)

Usage

kronSamp(A, B)

Arguments

A

an mxnm x n matrix

B

an pxqp x q matrix

Examples

A = matrix(c(1,.5,.5,1), ncol=2)
B = diag(2)
x = kronSamp(A, B)

Formatting for longitude scales in ggplot spatial maps

Description

Formatting for longitude scales in ggplot spatial maps

Usage

lat_trans()

Formatting for longitude scales in ggplot spatial maps

Description

Formatting for longitude scales in ggplot spatial maps

Usage

lon_trans()

Matern covariance

Description

This function evaluates the Matern covariance function for the elements of a vector.

Usage

maternArray(d, scale = 1, range = 1, smoothness = 0.5, nugget = 0)

Arguments

d

A numeric vector of distances at which the Matern correlation function should be evaluated.

scale

Scales correlations to covariances.

range

Matern range parameter. Controls the decay of pointwise correlations as a function of distance.

smoothness

Matern smoothness parameter. Controls the number of process derivatives.

nugget

Spatial covariance nugget.


Matern covariance

Description

This function evaluates the Matern covariance function for the elements of a (potentially non-square) spatial distance matrix

Usage

maternCov(d, scale = 1, range = 1, smoothness = 0.5, nugget = 0)

Arguments

d

A numeric vector or matrix of distances at which the Matern correlation function should be evaluated.

scale

Scales correlations to covariances.

range

Matern range parameter. Controls the decay of pointwise correlations as a function of distance.

smoothness

Matern smoothness parameter. Controls the number of process derivatives.

nugget

Spatial covariance nugget.

Examples

data("coprecip")
attach(coprecip)

# compute spatial covariance matrix for an exponential covariance function
# using Colorado coordinates
Sigma = maternCov(fields::rdist.earth(coords.s), scale = 1, range = 250,
  smoothness = .5, nugget = 0)

Compute effective range for Matern correlation to drop to a specified level

Description

The effective range for an isotropic spatial correlation function is commonly defined to be the distance beyond which the correlation becomes small, typically below .05. Given range and smoothness parameters for a Matern covariance function, this function numerically searches for this distance. Note that the scale is not important for this calculation.

Usage

maternEffectiveRange(cor = 0.05, range = 1, smoothness = 0.5)

Arguments

cor

Effective correlation to check for

range

Matern range parameter. Controls the decay of pointwise correlations as a function of distance.

smoothness

Matern smoothness parameter. Controls the number of process derivatives.

Examples

# effective range for exponential covariance function with range = 1,
# which is theoretically known to equal -ln(.05)
maternEffectiveRange(cor = .05, range = 1, smoothness = .5)

Combine results from composition sampler

Description

Combine results from composition sampler

Usage

mergeComposition(xfull, yfull)

Arguments

xfull

Raw output from one run of the Rcpp/Armadillo composition sampler

yfull

Raw output from another run of the Rcpp/Armadillo composition sampler


Combine sample covariance matrices from two samples

Description

This function combines the sample covariance information from two samples (of the same phenomena) to return the sample covariance matric of the union of the two samples.

Usage

mergeCovmat(
  A.cov.xy,
  B.cov.xy,
  A.mean.x,
  A.mean.y,
  B.mean.x,
  B.mean.y,
  A.n,
  B.n
)

Arguments

A.cov.xy

sample covariance matrix from the first sample, 'A'

B.cov.xy

sample covariance matrix from the second sample, 'B'

A.mean.x

sample mean from the first sample, 'A'

A.mean.y

sample mean from the first sample, 'A'

B.mean.x

sample mean from the second sample, 'B'

B.mean.y

sample mean from the second sample, 'B'

A.n

sample size from the first sample, 'A'

B.n

sample size from the second sample, 'B'

Details

This function assumes the data is normalized by n (the MLE estimator) instead of n-1 (the unbiased estimator).

References

Pebay, P., 2008, Formulas for Robust, One-Pass Parallel Computation of Covariances and Arbitrary-Order Statistical Moments: Sandia Report.


Combine sample means from two samples

Description

This function combines the sample mean information from two samples (of the same phenomena) to return the sample mean of the union of the two samples.

Usage

mergeMean(x.mean, y.mean, x.n, y.n)

Arguments

x.mean

sample mean from the first sample, 'x'

y.mean

sample mean from the second sample, 'y'

x.n

sample size from the first sample, 'x'

y.n

sample size from the second sample, 'y'


Combine sample variances from two samples

Description

This function combines the sample variance information from two samples (of the same phenomena) to return the sample variance of the union of the two samples.

Usage

mergeVar(x.var, y.var, x.mean, y.mean, x.n, y.n)

Arguments

x.var

sample variance from the first sample, 'x'

y.var

sample variance from the second sample, 'y'

x.mean

sample mean from the first sample, 'x'

y.mean

sample mean from the second sample, 'y'

x.n

sample size from the first sample, 'x'

y.n

sample size from the second sample, 'y'

Details

This function assumes the data is normalized by n (the MLE estimator) instead of n-1 (the unbiased estimator).

References

Chan, T.F., Golub, G.H., and LeVeque, R.J., 1979, Updating formulae and a pairwise algorithm for computing sample variances: Technical Report, Stanford University .


Plot stData objects

Description

This function provides basic plotting for telefit package data.

Usage

## S3 method for class 'stData'
plot(
  x,
  type = "response",
  t = NULL,
  p = NULL,
  map = "world",
  region = ".",
  coord.s = NULL,
  coord.r = NULL,
  zlim = NULL,
  fill.lab = NULL,
  lab.teleconnection = expression(alpha),
  fill.lab.width = 20,
  category.breaks = NULL,
  coords.knots = NULL,
  signif.telecon = F,
  dots = NULL,
  pattern = 1,
  lwd = 1.75,
  cutoff = 0.9,
  signif.level = 0.05,
  alpha = 0.2,
  zmid = 0,
  contour = c(F, F),
  ...
)

Arguments

x

Object of class stData to plot.

type

One of the following options to specify what type of plot to build

response
sd.response

Plot standard deviation of response variable at each location.

cat.response
covariate
remote
teleconnection

This plot only applies if the stData object contains information about teleconnection effects, i.e., if it is a simulated dataset or otherwise modified to include estimates of teleconnection effects.

remote_cor

This plot shows pointwise correlations between a local coordinate and the remote covariates.

eof
eof_scores
eof_scree
eof_cor

This plot shows pointwise correlations with EOF patterns.

local_cor

This plot shows pointwise correlations with local covariates.

teleconnection_knot_local
t

timepoint to plot. Will automatically plot the first timepoint if t=NULL.

p

column index of local covariate to plot if type='covariate'. Will automatically assume the local covariate data includes an intercept and will plot the second column if p=NULL.

map

name of map provided by the maps package. These include county, france, italy, nz, state, usa, world, world2. By default, all stData plots will include us state outlines.

region

name of subregions to include. Defaults to . which includes all subregions. See documentation for map for more details.

coord.s

if plot type is 'teleconnection', specifies the longitude and latitude of local coordinate for which to plot teleconnection effects. if NULL, the middle local coordinate will be plotted.

coord.r

if plot type is 'teleconnection_local', specifes the longitude and latitude of remote coordinate for which to plot associated teleconnection effects. if NULL, the middle remote coordinate will be plotted.

zlim

c(min, max) vector that specifies the colorscale limits

fill.lab

Optional label to override the default fill scale labels

lab.teleconnection

label used for fill scale in teleconnection plot

fill.lab.width

line width for fill scale label

category.breaks

[ncoords x ncats] list of breakpoints used for binning responses into categories

coords.knots

if plot type is 'remote', specifies the longitude and latitude of knot locations to overlay on the 'remote' plot

signif.telecon

if TRUE, will highlight significant grid cells if the plotting data contain a signif column

dots

additional named arguments with defaults to pass to additional functions

pattern

if type=='eof' this specifies which (remote) EOF pattern to plot or if type=='eof_scores' this (vector) specifies which (remote) EOF pattern scores to plot

lwd

line width for when plotting with signif.telecon==T

cutoff

Used to denote where this proportion of variance is achieved in the eof_scree plots

signif.level

significance level for eof_cor significance highlighting

alpha

the level of fading that should be applied to insignificant grid boxes when plotting significant effects

zmid

number that specifies the midpoint of the colorscale

contour

c(TRUE, TRUE) to plot local and remote responses as contours vs. observations

...

additional arguments to pass to functions

Value

a ggplot object with the specified map

Examples

data("coprecip")
p = plot(coprecip)

Plot stFit objects

Description

This function provides basic plotting for telefit package data.

Usage

## S3 method for class 'stFit'
plot(
  x,
  type = "density",
  stData = NULL,
  coord.s = NULL,
  coord.knot = NULL,
  text.size = NULL,
  axis.text.size = NULL,
  title.text.size = NULL,
  burn = 1,
  signif.telecon = F,
  p = 1,
  local.covariate = NULL,
  lwd = NULL,
  facet.signif = 3,
  stat.smooth.bw = NULL,
  stat.smooth.degree = NULL,
  dots = NULL,
  ...
)

Arguments

x

Object of class stFit to plot.

type

One of the following options to specify what type of plot to build

traceplot
density
pairs
teleconnection
teleconnection_local
teleconnection_knot
teleconnection_knot_transect
teleconnection_knot_influence
beta
stData

Object of class stData to provide coordinate and related information for plotting estimated teleconnection effects

coord.s

if plot type is 'teleconnection', specifies the longitude and latitude of local coordinate for which to plot estimated teleconnection effects. if NULL, the middle local coordinate will be plotted.

coord.knot

if plot type is 'teleconnection_knot_influence' or 'teleconnection_knot_local', specifies the longitude and latitude of knot coordinate for which to plot influence of remote coefficient on remote covariates, or the teleconnection coefficients associated with coord.knot

text.size

number specifying the size of text labels

axis.text.size

number specifying the size of axis text labels

title.text.size

number specifying the size of title

burn

number of observations to exclude from graph

signif.telecon

if TRUE, will highlight significant teleconnection effects when type=='teleconnection'

p

If stFit was fit with spatially varying coefficients, p specifies the index of the spatially varying coefficient to plot

local.covariate

data.frame with variables, 'lon.Y', 'lat.Y', 'x' that will be plotted against teleconnection effects if type=='teleconnection_knot_transect'

lwd

specifies linewidth for plots that include reference lines

facet.signif

number of significant figures to round facet latitudes and longitudes for if type=='teleconnection_knot_transect'

stat.smooth.bw

if type=='teleconnection_knot_transect' this specifies the bandwith of the non-parametric smooth of the estimates

stat.smooth.degree

if type=='teleconnection_knot_transect' this specifies the degree of the non-parametric smooth of the estimates

dots

additional named arguments with defaults to pass to additional functions

...

additional arguments to pass to functions

Value

a ggplot object with the specified map

Examples

data("coprecip.fit")
plot(coprecip.fit, burn = 50, type = 'trace')

Plot stPredict objects

Description

This function provides basic plotting for telefit package data.

Usage

## S3 method for class 'stPredict'
plot(
  x,
  type = "prediction",
  t = NULL,
  stFit = NULL,
  stData = NULL,
  err.comparison = NULL,
  err.var = NULL,
  err.lab = err.var,
  pattern = 1,
  dots = NULL,
  burn = 1,
  signif.telecon = F,
  ...
)

Arguments

x

Object of class stPredict to plot.

type

One of the following options to specify what type of plot to build

prediction

Spatial plot of predicted response variable for a given timepoint t.

residual

Spatial plot of residual for a given timepoint t. Note, this plot is only available if the model has been evaluated and the predictions have been compared to another response dataset.

observed

Spatial plot of observed response variable for a given timepoint t. Note, this plot is only available if the model has been evaluated and the predictions have been compared to another response dataset.

standard_error (or 'se')

Spatial plot of prediction standard errors for a given timepoint t.

local

Spatial plot of the local components of the response variable for a given timepoint t.

remote

Spatial plot of the remote components of the response variable for a given timepoint t.

w

Spatial plot of the spatial noise component of the reponse variable for a given timepoint t.

correlation

Scatterplot of observed vs. predicted response variables for a given timepoint t. Note, this plot is only available if the model has been evaluated and the predictions have been compared to another response dataset.

teleconnection

Spatial plot of remote coefficients associated with a location coord.s in the spatial response domain.

teleconnection_knot

Spatial plot of remote knot coefficients associated with a location coord.s in the spatial response domain.

teleconnection_knot_transect
errors

Series of plots that measure overall prediction error across prediction timepoints.

cat.prediction

Spatial plot of the predicted response variable category (i.e., above/below average) for a given timepoint t.

truth

Note, this plot is only available if the model has been evaluated and the predictions have been compared to another response dataset.

residual

Note, this plot is only available if the model has been evaluated and the predictions have been compared to another response dataset.

eof_alpha_knots

A map of the local domain where the plotted colors show the remote influence coefficients mapped onto the eof pattern specified by the "pattern" argument.

t

timepoint to plot. Will automatically plot the first timepoint if t=NULL.

stFit

Object of class stFit to provide related information and structures for plotting estimated teleconnection effects

stData

Object of class stData to provide coordinate and related information for plotting estimated teleconnection effects

err.comparison

data.frame with Year column and a column for a variable that will be used to plot annual errors against

err.var

name of variable in err.comparison for plotting against

err.lab

label for name of variable in err.comparison for plotting against

pattern

if type=='eof_alpha_knots', this specified which eof the remote coefficients should be mapped onto and then plotted over the local domain

dots

additional named arguments with defaults to pass to additional functions

burn

number of observations to exclude from graph

signif.telecon

TRUE to highlight significant teleconnection effects

...

additional arguments to be passed to lower-level plotting functions

Value

a ggplot object with the specified map

Examples

data("coprecip.predict")
p = plot(coprecip.predict, t=1981)

Plots teleconnection correlation maps

Description

This function provides basic plotting for analyses returned from cor.tel

Usage

## S3 method for class 'teleCor'
plot(
  x,
  signif = F,
  coord.s = NULL,
  map = "world",
  region = ".",
  zlim = NULL,
  dots = NULL,
  ...
)

Arguments

x

object of class teleCor, containing pointwise correlations

signif

if TRUE, then teleCor must have a column labeled 'signif' that indicates which correlations are significant. These correlations will be printed in bold, and the rest will be printed more lightly

coord.s

specifies the longitude and latitude of local coordinate for which to plot pointwise correlations (if type=='remote'). if NULL, the middle local coordinate will be plotted.

map

name of map provided by the maps package. These include county, france, italy, nz, state, usa, world, world2. By default, all stData plots will include us state outlines.

region

name of subregions to include. Defaults to . which includes all subregions. See documentation for map for more details.

zlim

c(min, max) vector that specifies the colorscale limits

dots

additional named arguments with defaults to pass to additional functions

...

additional arguments to be passed to lower-level plotting functions

Value

a ggplot object with the specified map

Examples

data("coprecip")

cors = teleCor(coprecip)
p = plot(cors, coords.s = c(-105, 39.73))

Simulate matrices from matrix normal distributions

Description

Draw random matrices from the matrix normal distribution

MN(M,U,V)MN(M, U, V)

Note that an observation, XX, from this equation has the following distribution when vectorized

vec(X) N(vec(M),kron(V,U))vec(X) ~ N(vec(M), kron(V, U) )

Usage

rmatnorm(n, U, V, M = matrix(0, nrow = nrow(U), ncol = nrow(V)))

Arguments

n

Number of random matrices to simulate

U

Covariance matrix defining dependence between rows

V

Covariance matrix defining dependence between columns

M

average value of each entry in the sampled matrices


Random wishart matrix

Description

Random wishart matrix

Usage

rwishart(V, n)

Arguments

V

symmetric positive definite p x p scale matrix

n

degrees of freedom (greater than p-1)


Basic evaluation of fit

Description

Provides basic measures for evalutating the fit. Includes Brier skill score against the climatology, MSPE, PPL, overall correlation, and a computation of the coverage probabilities for confidence intervals

Usage

stEval(forecast, Y, clim)

Arguments

forecast

stPredict object containing predictions for Y

Y

observed values of the response

clim

the climatology for the location in Y

Examples

data("coprecip")
data("coprecip.predict")

clim = rowMeans(coprecip$Y)
coprecip.predict = stEval(coprecip.predict, coprecip$Y, clim)

Fit the remote effects spatial process (RESP) model

Description

Fit the remote effects spatial process (RESP) model

Usage

stFit(
  stData = NULL,
  priors,
  maxIt,
  X = stData$X,
  Y = stData$Y,
  Z = stData$Z,
  coords.s = stData$coords.s,
  coords.r = stData$coords.r,
  rw.initsd = NULL,
  returnll = T,
  miles = T,
  C = 1,
  alpha = 0.44,
  localOnly = F,
  varying = F,
  remoteOnly = F,
  coords.knots
)

Arguments

stData

Object with class 'stData' containing data needed to fit this model. The data need only be manually entered if not using a stData object.

priors

A list containing parameters for the prior distributions. The list needs to contain the following values

beta

list(Lambda=matrix) specifying the prior covariance matrix for the local effects if varying==F, otherwise list(Psi=matrix, nu=double) specifying the Inverse wishart prior distribution for the spatially varying coefficient process if varying==T.

cov.s

list(smoothness=double, range=c(min, max), variance=c(shape, rate), nugget=c(shape, rate))

cov.r

list(smoothness=double, range=c(min, max), variance=c(shape, rate), nugget=c(shape, rate))

maxIt

number of iterations to run the MCMC chain for

X

[ns, p, nt] array of design matrices with local covariates

Y

[ns, nt] matrix with response data

Z

[nr, nt] matrix with remote covariates

coords.s

matrix with coordinates where responses were observed (lon, lat)

coords.r

matrix with coordinates where remote covariates were observed (lon, lat)

rw.initsd

A list containing initial standard deviation parameters for the MCMC parameters requiring random walk updates

cov.s

list(range=double, nugget=double)

cov.r

list(range=double, variance=double, nugget=double)

returnll

TRUE to compute the model log-likelihood at each iteration

miles

TRUE if covariance matrix distances should be in miles, FALSE for kilometers

C

scaling factor used in adapting random walk proposal variances.

alpha

target acceptance rate for random walk proposals.

localOnly

TRUE to fit the model without the teleconnection effects (typically for evaluating impact of teleconnection effects)

varying

(depreceated) TRUE to fit the model with spatially varying local coefficients

remoteOnly

TRUE to fit the model without local effects. This will fit a local intercept, but will not incorporate local covariates.

coords.knots

matrix with coordinates where remote teleconnections will be based (lon, lat)

Examples

library(dplyr)
library(foreach)
library(itertools)

set.seed(2018)

data("coprecip")
data("coprecip.fit")
attach(coprecip)

coprecip.fit = stFit(stData = coprecip, priors = coprecip.fit$priors, 
                     maxIt = 10, coords.knots = coprecip.fit$coords.knots)

Compute log likelihood for model

Description

Compute log likelihood for model

Usage

stLL(
  stData,
  stFit,
  beta,
  sigmasq_y,
  sigmasq_r,
  sigmasq_eps,
  rho_y,
  rho_r,
  X = stData$X,
  Y = stData$Y,
  Z = stData$Z,
  coords.s = stData$coords.s,
  coords.r = stData$coords.r,
  coords.knots = stFit$coords.knots,
  miles = TRUE,
  sigmasq_r_eps
)

Arguments

stData

Object with class 'stData' containing data needed to fit this model. The data need only be manually entered if not using a stData object.

stFit

Object with class 'stFit' containing posterior parameter samples needed to composition sample the teleconnection effects and generate posterior predictions. The data needed from stFit need only be manually entered if not using a stData object.

beta

values of β\beta at which to evaluate the likelihood

sigmasq_y

values of σw2\sigma^2_w at which to evaluate the likelihood

sigmasq_r

values of σα2\sigma^2_\alpha at which to evaluate the likelihood

sigmasq_eps

values of σε2\sigma^2_\varepsilon at which to evaluate the likelihood

rho_y

values of ρw\rho_w at which to evaluate the likelihood

rho_r

values of ρα\rho_\alpha at which to evaluate the likelihood

X

[ns, p, nt] array of design matrices with local covariates

Y

[ns, nt] matrix with response data

Z

[nr, nt] matrix with remote covariates

coords.s

matrix with coordinates where responses were observed (lon, lat)

coords.r

matrix with coordinates where remote covariates were observed (lon, lat)

coords.knots

matrix with coordinates of knots for remote covariates (lon, lat)

miles

TRUE if distances should be computed in miles (kilometers otherwise)

sigmasq_r_eps

values of σαε2\sigma^2_{\alpha_\varepsilon} at which to evaluate the likelihood

Examples

library(dplyr)
library(foreach)
library(itertools)

set.seed(2018)

data("coprecip")
data("coprecip.fit")
attach(coprecip)

ests = coef(coprecip.fit, burn = 50)

ll = stLL(stData = coprecip, stFit = coprecip.fit, 
          beta = matrix(ests$beta, ncol = 2), 
          sigmasq_y = ests$sigmasq_y, sigmasq_r = ests$sigmasq_r, 
          sigmasq_eps = ests$sigmasq_eps,
          rho_y = ests$rho_y, rho_r = ests$rho_r, 
          sigmasq_r_eps = 0)

Compute forecasts based on posterior samples

Description

Predict response at new timepoints by drawing samples of the response from the posterior predictive distribution. Since this requires sampling teleconnection effects, this method can return estimates of the teleconnection effects as a by-product.

Usage

stPredict(
  stFit,
  stData,
  stDataNew,
  burn = 1,
  prob = 0.95,
  ncores = 1,
  conf = 0.95,
  tLabs = stDataNew$tLabs,
  X = stData$X,
  Y = stData$Y,
  Z = stData$Z,
  Xnew = stDataNew$X,
  Znew = stDataNew$Z,
  coords.s = stData$coords.s,
  coords.r = stData$coords.r,
  returnAlphas = T,
  cat.probs = c(1/3, 2/3),
  returnFullAlphas = F
)

Arguments

stFit

Object with class 'stFit' containing posterior parameter samples needed to composition sample the teleconnection effects and generate posterior predictions. The data needed from stFit need only be manually entered if not using a stData object.

stData

Object with class 'stData' containing data needed to fit this model. The data need only be manually entered if not using a stData object.

stDataNew

object of class stData that includes information needed for making forecasts. If response data is included, this function will automatically run stEval using the empirical climatology as the reference forecast

burn

number of posterior samples to burn before drawing composition samples

prob

confidence level for approximate confidence intervals of teleconnection effects (only needed if returnAlphas==TRUE)

ncores

Since the teleconnection effects and posterior predictions can be sampled in parallel, this parameter lets users specify the number of cores to use to draw teleconnection and prediction samples

conf

Parameter specifying the HPD level to compute for posterior predictive samples

tLabs

Forecast timepoint labels

X

[ns, p, nt] array of design matrices with local covariates

Y

[ns, nt] matrix with response data

Z

[nr, nt] matrix with remote covariates

Xnew

[ns, p, nt0] array of design matrices with local covariates at forecast timepoints

Znew

[nr, nt0] matrix with remote covariates at forecast timepoints

coords.s

matrix with coordinates where responses were observed (lon, lat)

coords.r

matrix with coordinates where remote covariates were observed (lon, lat)

returnAlphas

TRUE to return the teleconnection effects sampled at knot locations. Note that only basic summary information about the teleconnection effects will be returned.

cat.probs

vector of probabilities for also returning categorical predictions from the posterior prediction samples; NULL otherwise

returnFullAlphas

TRUE to return the teleconnection effects. Note that only basic summary information about the teleconnection effects will be returned.

Examples

set.seed(2018)
  
data("coprecip")
data("coprecip.fit")

coprecip.predict = stPredict(stFit = coprecip.fit, stData = coprecip, 
                             stDataNew = coprecip, burn = 90, 
                             returnFullAlphas = FALSE)

Simulate responses from the spatio-temporal teleconnection model

Description

This function simulates spatio-temporal data. The intention is that data Y and latent parameters alpha will be generated using provided covariates X and Z; spatial domains coords.s, coords.r, and coords.knots; and model parameters.

Usage

stSimulate(dat.train, dat.test, coords.knots, params, miles = T)

Arguments

dat.train

stData object with training data to simulate new Y values for

dat.test

stData object with test data to simulate new Y values for

coords.knots

matrix with coordinates of knots for remote covariates (lon, lat)

params

A list containing model parameters for use in simulation

beta

vector with fixed effect coefficients

cov.s

list(smoothness=double, range=double, variance=double, nugget=double)

cov.r

list(smoothness=double, range=double, variance=double, nugget=double)

miles

TRUE to compute distances for evaluating covariance functions in miles. This is important since the interpretations of the cov.r and cov.s parameters depend on the units with which distance is measured.

Examples

set.seed(2018)
  
data("coprecip")
data("coprecip.fit")

coprecip.predict = stPredict(stFit = coprecip.fit, stData = coprecip, 
                             stDataNew = coprecip, burn = 90, 
                             returnFullAlphas = FALSE)

Computes variance inflation factors for fixed effects of the teleconnection model

Description

VIFs will be computed at the posterior mean of all covariance parameters.

Usage

stVIF(stData, stFit, burn)

Arguments

stData

Object with class 'stData' containing data needed to fit this model.

stFit

Object with class 'stFit' containing posterior parameter samples needed to composition sample the teleconnection effects and generate posterior predictions.

burn

number of posterior samples to burn before drawing composition samples

Examples

data("coprecip")
data("coprecip.fit")

stVIF(stData = coprecip, stFit = coprecip.fit, burn = 50)

Summarize alphas

Description

This function computes approximate normal intervals, etc. for fitted alphas.

Usage

summariseAlpha(alpha, prob = 0.95, coords.s, coords.r)

Arguments

alpha

structure containing posterior inference for remote coefficients

prob

confidence level for confidence intervals and significance

coords.s

matrix with coordinates where responses were observed (lon, lat)

coords.r

matrix with coordinates where remote covariates were observed (lon, lat)

Examples

## Not run: 
data("coprecip")
data("coprecip.fit")
attach(coprecip)

# sample posterior predictive distributions AND estimate teleconnection effects
coprecip.precict = stPredict(stFit = coprecip.fit, stData = coprecip, 
                             stDataNew = coprecip, burn = 90, 
                             returnFullAlphas = TRUE)

alpha.90 = summariseAlpha(alpha = coprecip.precict$alpha, prob = .9, 
                          coords.s = coords.s, coords.r = coords.r)

## End(Not run)

Summarize eof-mapped alphas

Description

This function computes approximate normal intervals, etc. for fitted eof-mapped alphas.

Usage

summariseEOFAlpha(eof_alpha, prob = 0.95, coords.s)

Arguments

eof_alpha

structure containing posterior inference for transformed remote coefficients

prob

confidence level for confidence intervals and significance

coords.s

matrix with coordinates where responses were observed (lon, lat)

Examples

data("coprecip.predict")
attach(coprecip.predict)

alpha.eof.90 = summariseEOFAlpha(eof_alpha = eof_alpha_knots, prob = .9, 
  coords.s = coords.s)

Plot stPredict objects

Description

This function prints basic summary info for telefit stPredict objects

Usage

## S3 method for class 'stPredict'
summary(object, t = NULL, digits = NULL, ...)

Arguments

object

Object of class stPredict to summarise

t

timepoint to plot. Will automatically plot all timepoints and overall summary if NULL.

digits

Number of digits to pass to signif, if not NULL.

...

S3 generic/method consistency

Examples

data("coprecip.predict")
summary(coprecip.predict)

Fit a spatially varying coefficient model

Description

Fit a spatially varying coefficient model

Usage

svcFit(
  y,
  X,
  z,
  coords,
  miles = T,
  priors,
  nSamples,
  thin = 1,
  rw.initsd = 0.1,
  inits = list(),
  C = 1,
  alpha = 0.44
)

Arguments

y

vector containing responses for each timepoint. vector is blocked by timepoint.

X

matrix containing local covariates for each timepoint. each row are the covariates for one location and timepoint. matrix is blocked by timepoint.

z

matrix containing remote covariates. each column has remote covariates for one timepoint.

coords

n x 2 matrix containing lon-lat coordinates for locations.

miles

T/F for whether to compute great circle distances in miles (T) or km (F)

priors

A list containing parameters for the prior distributions. The list needs to contain the following values

T

list(Psi=matrix, nu=double) specifying the Inverse wishart prior distribution for the spatially varying coefficient process.

beta

list(Linv=matrix) specifying the prior precision matrix for the fixed local covariates.

sigmasq

list(a=double, b=double) specifying the prior shape and scale parameters for the covariance scale and nugget parameters.

rho

list(L=double, U=double) specifying the lower and upper bounds for the spatial range parameter.

cov

list(nu=double) specifying the smoothness for the matern covariance.

nSamples

number of MCMC iterations to run

thin

MCMC thinning; defaults to no thinning (thin=1)

rw.initsd

Initial proposal standard deviation for RW samplers

inits

optional list containing starting parameters for MCMC sampler

C

scaling factor used in adapting random walk proposal variances.

alpha

target acceptance rate for random walk proposals.

Examples

library(fields)
library(mvtnorm)

set.seed(2018)

# set key parameters
dims = list(N=100, nt=3, k=2, p=2)
params = list(sigmasq=.2, rho=.3, eps=.5, nu=.5)

# generate parameters and data
coords = matrix( runif(2 * dims$N), ncol = 2 )
X = matrix( rnorm(dims$p * dims$N * dims$nt), ncol = dims$p )
beta = c(-1, .5)
z = matrix( rnorm(dims$k * dims$nt), ncol = dims$nt)
H = maternCov(rdist.earth(coords), scale = params$sigmasq, range = params$rho,
              smoothness = params$nu, nugget = params$sigmasq * params$eps)
Hinv = solve(H)
Tm = matrix(c(.5,.2, .2, .5), ncol=2)/2
theta = kronSamp(Hinv, Tm)


# generate response
xb = X %*% beta
zt = as.numeric(apply(z, 2, function(d) { 
  kronecker(diag(dims$N), t(d)) %*% theta }))
w = kronSamp(diag(dims$nt), H)
y =  xb + zt + w


# fit model
it = 100
priors = list(
  T = list(Psi = .1*diag(dims$k), nu = dims$k),
  beta = list(Linv = diag(dims$p) * 1e-2),
  sigmasq = list(a=2, b=1),
  rho = list(L=0, U=1),
  cov = list(nu=.5)
)

fit = svcFit(y=y, X=X, z=z, coords=coords, priors=priors, nSamples=it)


#
# predict at new timepoints
#

# generate parameters and data
nt0 = 3
Xn = matrix( rnorm(dims$p * dims$N * nt0), ncol = dims$p )
zn = matrix( rnorm(dims$k * nt0), ncol = nt0)

# generate response
xbn = Xn %*% beta
ztn = as.numeric(apply(zn, 2, function(d) { 
  kronecker(diag(dims$N), t(d)) %*% theta }))
wn = kronSamp(diag(nt0), H)
yn =  xbn + ztn + wn

# predict responses
pred = svcPredict(fit, Xn, zn, burn = 50)

Make predictions using a fitted varying coefficient model

Description

Make predictions using a fitted varying coefficient model

Usage

svcPredict(
  fit,
  Xn = NULL,
  Zn = NULL,
  stData = NULL,
  stDataNew = NULL,
  burn = 0,
  cat.probs = c(1/3, 2/3),
  conf = 0.95
)

Arguments

fit

svcFit object containing posterior samples

Xn

[nr*nt, p] matrix of local covariates at new timepoint

Zn

[nr, nt] matrix of remote covariates at new timepoints

stData

Object with class 'stData' containing data needed to fit this model. The data is used to compute empirical quantiles for making categorical predictions.

stDataNew

object of class stData that includes information needed for making forecasts.

burn

number of posterior samples to burn from fit

cat.probs

vector of probabilities for also returning categorical predictions from the posterior prediction samples; NULL otherwise

conf

Parameter specifying the HPD level to compute for posterior predictive samples

Examples

library(fields)
library(mvtnorm)

set.seed(2018)

# set key parameters
dims = list(N=100, nt=3, k=2, p=2)
params = list(sigmasq=.2, rho=.3, eps=.5, nu=.5)

# generate parameters and data
coords = matrix( runif(2 * dims$N), ncol = 2 )
X = matrix( rnorm(dims$p * dims$N * dims$nt), ncol = dims$p )
beta = c(-1, .5)
z = matrix( rnorm(dims$k * dims$nt), ncol = dims$nt)
H = maternCov(rdist.earth(coords), scale = params$sigmasq, range = params$rho,
              smoothness = params$nu, nugget = params$sigmasq * params$eps)
Hinv = solve(H)
Tm = matrix(c(.5,.2, .2, .5), ncol=2)/2
theta = kronSamp(Hinv, Tm)


# generate response
xb = X %*% beta
zt = as.numeric(apply(z, 2, function(d) { 
  kronecker(diag(dims$N), t(d)) %*% theta }))
w = kronSamp(diag(dims$nt), H)
y =  xb + zt + w


# fit model
it = 100
priors = list(
  T = list(Psi = .1*diag(dims$k), nu = dims$k),
  beta = list(Linv = diag(dims$p) * 1e-2),
  sigmasq = list(a=2, b=1),
  rho = list(L=0, U=1),
  cov = list(nu=.5)
)

fit = svcFit(y=y, X=X, z=z, coords=coords, priors=priors, nSamples=it)


#
# predict at new timepoints
#

# generate parameters and data
nt0 = 3
Xn = matrix( rnorm(dims$p * dims$N * nt0), ncol = dims$p )
zn = matrix( rnorm(dims$k * nt0), ncol = nt0)

# generate response
xbn = Xn %*% beta
ztn = as.numeric(apply(zn, 2, function(d) { 
  kronecker(diag(dims$N), t(d)) %*% theta }))
wn = kronSamp(diag(nt0), H)
yn =  xbn + ztn + wn

# predict responses
pred = svcPredict(fit, Xn, zn, burn = 50)

Pointwise correlations for an exploratory teleconnection analysis

Description

Computes empirical correlations between rows of Y and Z, for use as exploratory analysis of teleconnection patterns between locations indexed by coords.s and coords.r. Optionally, an stData object containing Y and Z can be passed instead.

Usage

teleCor(
  stData = NULL,
  Y = stData$Y,
  Z = stData$Z,
  coords.s = stData$coords.s,
  coords.r = stData$coords.r
)

Arguments

stData

stData object containing data to analyze

Y

[ny x nt] a matrix composed of nyny row vectors, each of which contains ntnt observations fom a different spatial location. Spatial locations for Y are indexed by coords.s.

Z

[nz x nt] a matrix composed of nznz row vectors each of which contains ntnt observations from a different spatial location. Spatial locations for Z are indexed by coords.r.

coords.s

coordinates of locations in Y

coords.r

coordinates of locations in Z

Value

list with a matrix 'cor' containing correlations. The columns index remote coordinates, while the rows index the local coordinates. The returned list also includes the coordinates.

Examples

data("coprecip")

cors = teleCor(coprecip)

Tools for modeling teleconnections

Description

The package telefit provides functions for fitting the remote effects spatial process (RESP) model.