,
Finn Lindgren [aut] ,
Suen Man Ho [ctb]| Title: | Excursion Sets and Contour Credibility Regions for Random Fields |
|---|---|
| Description: | Functions that compute probabilistic excursion sets, contour credibility regions, contour avoiding regions, and simultaneous confidence bands for latent Gaussian random processes and fields. The package also contains functions that calculate these quantities for models estimated with the INLA package. The main references for excursions are Bolin and Lindgren (2015) <doi:10.1111/rssb.12055>, Bolin and Lindgren (2017) <doi:10.1080/10618600.2016.1228537>, and Bolin and Lindgren (2018) <doi:10.18637/jss.v086.i05>. These can be generated by the citation function in R. |
| Authors: | David Bolin [cre, aut] ,
Finn Lindgren [aut] ,
Suen Man Ho [ctb] |
| Maintainer: | David Bolin <[email protected]> |
| License: | GPL (>=3) |
| Version: | 2.5.8.9001 |
| Built: | 2024-11-02 17:13:56 UTC |
| Source: | https://github.com/davidbolin/excursions |
excursions contains functions that compute probabilistic excursion sets,
contour credibility regions, contour avoiding regions, contour map quality measures,
and simultaneous confidence bands for latent Gaussian
random processes and fields. A detailed manual can be found in the paper
Bolin, D and Lindgren, F (2018)
Calculating Probabilistic Excursion Sets and Related Quantities Using excursions,
Journal of Statistical Software, 86(5), 1–20.
The main functions in the package fall into three different categories described below.
Excursion sets, contour credibility regions, and contour avoiding regions
The main functions for computing excursion sets, contour credibility regions, and contour avoiding regions are
excursions() The main function for Gaussian models.
excursions.inla() Interface for latent Gaussian models estimated using INLA.
excursions.mc() Function for analyzing models that have been estimated using Monte Carlo methods.
The output from the functions above provides a discrete domain estimate of the regions.
Based on this estimate, the function continuous() computes a continuous
domain estimate.
The main reference for these functions is Bolin, D. and Lindgren, F. (2015) Excursion and contour uncertainty regions for latent Gaussian models, JRSS-series B, vol 77, no 1, pp 85-106.
Contour map quality measures
The package provides several functions for computing contour maps and their quality measures. These quality measures can be used to decide on an appropriate number of contours to use for the contour map.
The main functions for computing contour maps and the corresponding quality measures are
contourmap() The main function for Gaussian models.
contourmap.inla() Interface for latent Gaussian models estimated using INLA.
contourmap.mc() Function for analyzing models that have been estimated using Monte Carlo methods.
Other noteworthy functions relating to contourmaps are tricontour() and
tricontourmap(), which compute contour curves for functinos defined on
triangulations, as well as contourmap.colors() which can be used to
compute appropriate colors for displaying contour maps.
The main reference for these functions is Bolin, D. and Lindgren, F. (2017) Quantifying the uncertainty of contour maps, Journal of Computational and Graphical Statistics, 26:3, 513-524.
Simultaneous confidence bands
The main functions for computing simultaneous confidence bands are
simconf() Function for analyzing Gaussian models.
simconf.inla() Function for analyzing latent Gaussian models estimated using INLA.
simconf.mc() Function for analyzing models estimated using Monte Carlo methods.
simconf.mixture() Function for analyzing Gaussian mixture models.
The main reference for these functions is Bolin et al. (2015) Statistical prediction of global sea level from global temperature, Statistica Sinica, Vol 25, pp 351-367.
Maintainer: David Bolin [email protected] (ORCID)
Authors:
Finn Lindgren [email protected] (ORCID)
Other contributors:
Suen Man Ho [email protected] [contributor]
Useful links:
Report bugs at https://github.com/davidbolin/excursions/issues
Calculates continuous domain excursion and credible contour sets
continuous( ex, geometry, alpha, method = c("log", "linear", "step"), output = c("sp", "fm", "inla"), subdivisions = 1, calc.credible = TRUE )continuous( ex, geometry, alpha, method = c("log", "linear", "step"), output = c("sp", "fm", "inla"), subdivisions = 1, calc.credible = TRUE )
ex |
An |
geometry |
Specification of the lattice or triangulation geometry of the input.
One of |
alpha |
The target error probability. A warning is given if it is detected
that the information |
method |
The spatial probability interpolation transformation method to use.
One of |
output |
Specifies what type of object should be generated. |
subdivisions |
The number of mesh triangle subdivisions to perform for the
interpolation of the excursions or contour function. 0 is no subdivision.
The setting has a small effect on the evaluation of |
calc.credible |
Logical, if TRUE (default), calculate credible contour region objects in addition to avoidance sets. |
A list with elements
M |
|
F |
Interpolated F function. |
G |
Contour and inter-level set indices for the interpolation. |
F.geometry |
Mesh geometry for the interpolation. |
P0 |
P0 measure based on interpolated F function (only for |
Finn Lindgren [email protected]
Bolin, D. and Lindgren, F. (2017) Quantifying the uncertainty of contour maps, Journal of Computational and Graphical Statistics, vol 26, no 3, pp 513-524.
Bolin, D. and Lindgren, F. (2018), Calculating Probabilistic Excursion Sets and Related Quantities Using excursions, Journal of Statistical Software, vol 86, no 1, pp 1-20.
## Not run: if (require("fmesher") && require("sp")) { # Generate mesh and SPDE model n.lattice <- 10 # Increase for more interesting, but slower, examples x <- seq(from = 0, to = 10, length.out = n.lattice) lattice <- fm_lattice_2d(x = x, y = x) mesh <- fm_rcdt_2d_inla(lattice = lattice, extend = FALSE, refine = FALSE) # Generate an artificial sample sigma2.e <- 0.1 n.obs <- 100 obs.loc <- cbind( runif(n.obs) * diff(range(x)) + min(x), runif(n.obs) * diff(range(x)) + min(x) ) Q <- fm_matern_precision(mesh, alpha = 2, rho = 3, sigma = 1) x <- fm_sample(n = 1, Q = Q) A <- fm_basis(mesh, loc = obs.loc) Y <- as.vector(A %*% x + rnorm(n.obs) * sqrt(sigma2.e)) ## Calculate posterior Q.post <- (Q + (t(A) %*% A) / sigma2.e) mu.post <- as.vector(solve(Q.post, (t(A) %*% Y) / sigma2.e)) vars.post <- excursions.variances(chol(Q.post), max.threads = 1) ## Calculate contour map with two levels map <- contourmap( n.levels = 2, mu = mu.post, Q = Q.post, alpha = 0.1, F.limit = 0.1, max.threads = 1 ) ## Calculate the continuous representation sets <- continuous(map, mesh, alpha = 0.1) ## Plot the results reo <- mesh$idx$lattice cols <- contourmap.colors(map, col = heat.colors(100, 1, rev = TRUE), credible.col = grey(0.5, 1) ) names(cols) <- as.character(-1:2) par(mfrow = c(2, 2)) image(matrix(mu.post[reo], n.lattice, n.lattice), main = "mean", axes = FALSE, asp = 1 ) image(matrix(sqrt(vars.post[reo]), n.lattice, n.lattice), main = "sd", axes = FALSE, asp = 1 ) image(matrix(map$M[reo], n.lattice, n.lattice), col = cols, axes = FALSE, asp = 1 ) idx.M <- setdiff(names(sets$M), "-1") plot(sets$M[idx.M], col = cols[idx.M]) } ## End(Not run)## Not run: if (require("fmesher") && require("sp")) { # Generate mesh and SPDE model n.lattice <- 10 # Increase for more interesting, but slower, examples x <- seq(from = 0, to = 10, length.out = n.lattice) lattice <- fm_lattice_2d(x = x, y = x) mesh <- fm_rcdt_2d_inla(lattice = lattice, extend = FALSE, refine = FALSE) # Generate an artificial sample sigma2.e <- 0.1 n.obs <- 100 obs.loc <- cbind( runif(n.obs) * diff(range(x)) + min(x), runif(n.obs) * diff(range(x)) + min(x) ) Q <- fm_matern_precision(mesh, alpha = 2, rho = 3, sigma = 1) x <- fm_sample(n = 1, Q = Q) A <- fm_basis(mesh, loc = obs.loc) Y <- as.vector(A %*% x + rnorm(n.obs) * sqrt(sigma2.e)) ## Calculate posterior Q.post <- (Q + (t(A) %*% A) / sigma2.e) mu.post <- as.vector(solve(Q.post, (t(A) %*% Y) / sigma2.e)) vars.post <- excursions.variances(chol(Q.post), max.threads = 1) ## Calculate contour map with two levels map <- contourmap( n.levels = 2, mu = mu.post, Q = Q.post, alpha = 0.1, F.limit = 0.1, max.threads = 1 ) ## Calculate the continuous representation sets <- continuous(map, mesh, alpha = 0.1) ## Plot the results reo <- mesh$idx$lattice cols <- contourmap.colors(map, col = heat.colors(100, 1, rev = TRUE), credible.col = grey(0.5, 1) ) names(cols) <- as.character(-1:2) par(mfrow = c(2, 2)) image(matrix(mu.post[reo], n.lattice, n.lattice), main = "mean", axes = FALSE, asp = 1 ) image(matrix(sqrt(vars.post[reo]), n.lattice, n.lattice), main = "sd", axes = FALSE, asp = 1 ) image(matrix(map$M[reo], n.lattice, n.lattice), col = cols, axes = FALSE, asp = 1 ) idx.M <- setdiff(names(sets$M), "-1") plot(sets$M[idx.M], col = cols[idx.M]) } ## End(Not run)
contourmap is used for calculating contour maps and quality measures for contour maps for Gaussian models.
contourmap( mu, Q, vars, n.levels, ind, levels, type = c("standard", "pretty", "equalarea", "P0-optimal", "P1-optimal", "P2-optimal"), compute = list(F = TRUE, measures = NULL), use.marginals = TRUE, alpha, F.limit, n.iter = 10000, verbose = FALSE, max.threads = 0, seed = NULL )contourmap( mu, Q, vars, n.levels, ind, levels, type = c("standard", "pretty", "equalarea", "P0-optimal", "P1-optimal", "P2-optimal"), compute = list(F = TRUE, measures = NULL), use.marginals = TRUE, alpha, F.limit, n.iter = 10000, verbose = FALSE, max.threads = 0, seed = NULL )
mu |
Expectation vector. |
Q |
Precision matrix. |
vars |
Precomputed marginal variances (optional). |
n.levels |
Number of levels in contour map. |
ind |
Indices of the nodes that should be analyzed (optional). |
levels |
Levels to use in contour map. |
type |
Type of contour map. One of:
|
compute |
A list with quality indices to compute
|
use.marginals |
Only marginal distributions are used when finding P-optimal maps (default TRUE). |
alpha |
Maximal error probability in contour map function (default=1). |
F.limit |
The limit value for the computation of the F function. F is set to NA for all nodes where F<1-F.limit. Default is F.limit = |
n.iter |
Number or iterations in the MC sampler that is used for calculating the quantities in |
verbose |
Set to TRUE for verbose mode (optional). |
max.threads |
Decides the number of threads the program can use. Set to 0 for using the maximum number of threads allowed by the system (default). |
seed |
Random seed (optional). |
The Gaussian model is specified using the mean mu and the precision matrix
Q. The contour map is then computed for the mean, using either the contour
levels specified in levels, or n.levels contours that are placed according
to the argument type.
A number of quality measures can be computed based based on the specified contour map
and the Gaussian distribution. What should be computed is specified using the
compute argument. For details on these quanties, see the reference below.
contourmap returns an object of class "excurobj" with the following elements
u |
Contour levels used in the contour map. |
n.levels |
The number of contours used. |
u.e |
The values associated with the level sets G_k. |
G |
A vector which shows which of the level sets G_k each node belongs to. |
map |
Representation of the contour map with |
F |
The contour map function (if computed). |
M |
Contour avoiding sets (if |
P0/P1/P2 |
Calculated quality measures (if computed). |
P0bound/P1bound/P2bound |
Calculated upper bounds quality measures (if computed). |
meta |
A list containing various information about the calculation. |
David Bolin [email protected]
Bolin, D. and Lindgren, F. (2017) Quantifying the uncertainty of contour maps, Journal of Computational and Graphical Statistics, vol 26, no 3, pp 513-524.
Bolin, D. and Lindgren, F. (2018), Calculating Probabilistic Excursion Sets and Related Quantities Using excursions, Journal of Statistical Software, vol 86, no 1, pp 1-20.
contourmap.inla(), contourmap.mc(), contourmap.colors()
n <- 10 Q <- Matrix(toeplitz(c(1, -0.5, rep(0, n - 2)))) mu <- seq(-5, 5, length = n) lp <- contourmap(mu, Q, n.levels = 2, compute = list(F = FALSE, measures = c("P1", "P2")), max.threads = 1 ) # Plot the contourmap plot(lp$map) # Display the quality measures cat(c(lp$P1, lp$P2))n <- 10 Q <- Matrix(toeplitz(c(1, -0.5, rep(0, n - 2)))) mu <- seq(-5, 5, length = n) lp <- contourmap(mu, Q, n.levels = 2, compute = list(F = FALSE, measures = c("P1", "P2")), max.threads = 1 ) # Plot the contourmap plot(lp$map) # Display the quality measures cat(c(lp$P1, lp$P2))
contourmap.colors calculates suitable colours for displaying contour maps.
contourmap.colors(lp, zlim, col, credible.col)contourmap.colors(lp, zlim, col, credible.col)
lp |
A contourmap calculated by |
zlim |
The range that should be used (optional). The default is the range of the mean value function used when creating the contourmap. |
col |
The colormap that the colours should be taken from. |
credible.col |
The color that should be used for displaying the credible regions for the contour curves (optional). |
A color map.
David Bolin [email protected]
n <- 10 Q <- Matrix(toeplitz(c(1, -0.5, rep(0, n - 2)))) map <- contourmap( mu = seq(-5, 5, length = n), Q, n.levels = 2, compute = list(F = FALSE), max.threads = 1 ) cols <- contourmap.colors(map, col = heat.colors(100, 1), credible.col = grey(0.5, 1) )n <- 10 Q <- Matrix(toeplitz(c(1, -0.5, rep(0, n - 2)))) map <- contourmap( mu = seq(-5, 5, length = n), Q, n.levels = 2, compute = list(F = FALSE), max.threads = 1 ) cols <- contourmap.colors(map, col = heat.colors(100, 1), credible.col = grey(0.5, 1) )
An interface to the contourmap function for latent Gaussian models
calculated using the INLA method.
contourmap.inla( result.inla, stack, name = NULL, tag = NULL, method = "QC", n.levels, type = c("standard", "pretty", "equalarea"), compute = list(F = TRUE, measures = NULL), alpha, F.limit, n.iter = 10000, verbose = FALSE, max.threads = 0, compressed = TRUE, seed = NULL, ind, ... )contourmap.inla( result.inla, stack, name = NULL, tag = NULL, method = "QC", n.levels, type = c("standard", "pretty", "equalarea"), compute = list(F = TRUE, measures = NULL), alpha, F.limit, n.iter = 10000, verbose = FALSE, max.threads = 0, compressed = TRUE, seed = NULL, ind, ... )
result.inla |
Result object from INLA call. |
stack |
The stack object used in the INLA call. |
name |
The name of the component for which to do the calculation. This argument should only be used if a stack object is not provided, use the tag argument otherwise. |
tag |
The tag of the component in the stack for which to do the calculation. This argument should only be used if a stack object is provided, use the name argument otherwise. |
method |
Method for handeling the latent Gaussian structure. Currently only Empirical Bayes (EB) and Quantile corrections (QC) are supported. |
n.levels |
Number of levels in contour map. |
type |
Type of contour map. One of:
|
compute |
A list with quality indices to compute
|
alpha |
Maximal error probability in contour map function (default=1) |
F.limit |
The limit value for the computation of the F function. F is
set to NA for all nodes where F<1-F.limit. Default is F.limit = |
n.iter |
Number or iterations in the MC sampler that is used for
calculating the quantities in |
verbose |
Set to TRUE for verbose mode (optional) |
max.threads |
Decides the number of threads the program can use. Set to 0 for using the maximum number of threads allowed by the system (default). |
compressed |
If INLA is run in compressed mode and a part of the linear predictor is to be used, then only add the relevant part. Otherwise the entire linear predictor is added internally (default TRUE). |
seed |
Random seed (optional). |
ind |
If only a part of a component should be used in the calculations, this argument specifies the indices for that part (optional). |
... |
Additional arguments to the contour map function. See the
documentation for |
The INLA approximation of the quantity of interest is in general a weighted
sum of Gaussian distributions with different parameters. If
method = 'EB' is used, then the contour map is computed for the mean
of the component in the weighted sum that has parameters with the highest
likelihood. If on the other hand method='QC', then the contour map is
computed for the posterior mean reported by INLA. If the EB method also is
used in INLA, then this reported posterior mean is equal to the mean of the
component with the highest likelihood. Therefore, method='EB' is
appropriate if the EB method also is used in INLA, but method='QC'
should be used in general.
The n.levels contours in the contour map are are placed according
to the argument type. A number of quality measures can be computed
based based on the specified contour map and the distribution of the
component of interest. What should be computed is specified using the
compute argument. For details on these quanties, see the reference
below.
contourmap.inla returns an object of class "excurobj" with the
same elements as returned by contourmap.
This function requires the INLA package, which is not a CRAN
package. See https://www.r-inla.org/download-install for easy
installation instructions.
David Bolin [email protected]
Bolin, D. and Lindgren, F. (2017) Quantifying the uncertainty of contour maps, Journal of Computational and Graphical Statistics, 26:3, 513-524.
Bolin, D. and Lindgren, F. (2018), Calculating Probabilistic Excursion Sets and Related Quantities Using excursions, Journal of Statistical Software, vol 86, no 1, pp 1-20.
contourmap(), contourmap.mc(),
contourmap.colors()
## Not run: if (require.nowarnings("INLA")) { # Generate mesh and SPDE model n.lattice <- 10 # increase for more interesting, but slower, examples x <- seq(from = 0, to = 10, length.out = n.lattice) lattice <- fmesher::fm_lattice_2d(x = x, y = x) mesh <- fmesher::fm_rcdt_2d_inla(lattice = lattice, extend = FALSE, refine = FALSE) spde <- inla.spde2.matern(mesh, alpha = 2) # Generate an artificial sample sigma2.e <- 0.01 n.obs <- 100 obs.loc <- cbind( runif(n.obs) * diff(range(x)) + min(x), runif(n.obs) * diff(range(x)) + min(x) ) Q <- inla.spde2.precision(spde, theta = c(log(sqrt(0.5)), log(sqrt(1)))) x <- inla.qsample(Q = Q, num.threads = 1) A <- fmesher::fm_basis(mesh = mesh, loc = obs.loc) Y <- as.vector(A %*% x + rnorm(n.obs) * sqrt(sigma2.e)) ## Estimate the parameters using INLA mesh.index <- inla.spde.make.index(name = "field", n.spde = spde$n.spde) ef <- list(c(mesh.index, list(Intercept = 1))) s.obs <- inla.stack(data = list(y = Y), A = list(A), effects = ef, tag = "obs") s.pre <- inla.stack(data = list(y = NA), A = list(1), effects = ef, tag = "pred") stack <- inla.stack(s.obs, s.pre) formula <- y ~ -1 + Intercept + f(field, model = spde) result <- inla( formula = formula, family = "normal", data = inla.stack.data(stack), control.predictor = list( A = inla.stack.A(stack), compute = TRUE ), control.compute = list( config = TRUE, return.marginals.predictor = TRUE ), num.threads = 1 ) ## Calculate contour map with two levels map <- contourmap.inla(result, stack = stack, tag = "pred", n.levels = 2, alpha = 0.1, F.limit = 0.1, max.threads = 1 ) ## Plot the results cols <- contourmap.colors(map, col = heat.colors(100, 1), credible.col = grey(0.5, 1) ) image(matrix(map$M[mesh$idx$lattice], n.lattice, n.lattice), col = cols) } ## End(Not run)## Not run: if (require.nowarnings("INLA")) { # Generate mesh and SPDE model n.lattice <- 10 # increase for more interesting, but slower, examples x <- seq(from = 0, to = 10, length.out = n.lattice) lattice <- fmesher::fm_lattice_2d(x = x, y = x) mesh <- fmesher::fm_rcdt_2d_inla(lattice = lattice, extend = FALSE, refine = FALSE) spde <- inla.spde2.matern(mesh, alpha = 2) # Generate an artificial sample sigma2.e <- 0.01 n.obs <- 100 obs.loc <- cbind( runif(n.obs) * diff(range(x)) + min(x), runif(n.obs) * diff(range(x)) + min(x) ) Q <- inla.spde2.precision(spde, theta = c(log(sqrt(0.5)), log(sqrt(1)))) x <- inla.qsample(Q = Q, num.threads = 1) A <- fmesher::fm_basis(mesh = mesh, loc = obs.loc) Y <- as.vector(A %*% x + rnorm(n.obs) * sqrt(sigma2.e)) ## Estimate the parameters using INLA mesh.index <- inla.spde.make.index(name = "field", n.spde = spde$n.spde) ef <- list(c(mesh.index, list(Intercept = 1))) s.obs <- inla.stack(data = list(y = Y), A = list(A), effects = ef, tag = "obs") s.pre <- inla.stack(data = list(y = NA), A = list(1), effects = ef, tag = "pred") stack <- inla.stack(s.obs, s.pre) formula <- y ~ -1 + Intercept + f(field, model = spde) result <- inla( formula = formula, family = "normal", data = inla.stack.data(stack), control.predictor = list( A = inla.stack.A(stack), compute = TRUE ), control.compute = list( config = TRUE, return.marginals.predictor = TRUE ), num.threads = 1 ) ## Calculate contour map with two levels map <- contourmap.inla(result, stack = stack, tag = "pred", n.levels = 2, alpha = 0.1, F.limit = 0.1, max.threads = 1 ) ## Plot the results cols <- contourmap.colors(map, col = heat.colors(100, 1), credible.col = grey(0.5, 1) ) image(matrix(map$M[mesh$idx$lattice], n.lattice, n.lattice), col = cols) } ## End(Not run)
contourmap.mc is used for calculating contour maps and quality measures for contour maps based on Monte Carlo samples of a model.
contourmap.mc( samples, n.levels, ind, levels, type = c("standard", "equalarea", "P0-optimal", "P1-optimal", "P2-optimal"), compute = list(F = TRUE, measures = NULL), alpha, verbose = FALSE )contourmap.mc( samples, n.levels, ind, levels, type = c("standard", "equalarea", "P0-optimal", "P1-optimal", "P2-optimal"), compute = list(F = TRUE, measures = NULL), alpha, verbose = FALSE )
samples |
Matrix with model Monte Carlo samples. Each column contains a sample of the model. |
n.levels |
Number of levels in contour map. |
ind |
Indices of the nodes that should be analyzed (optional). |
levels |
Levels to use in contour map. |
type |
Type of contour map. One of:
|
compute |
A list with quality indices to compute
|
alpha |
Maximal error probability in contour map function (default=0.1). |
verbose |
Set to TRUE for verbose mode (optional). |
The contour map is computed for the empirical mean of the samples.
See contourmap() and contourmap.inla() for further details.
contourmap returns an object of class "excurobj" with the following elements
u |
Contour levels used in the contour map. |
n.levels |
The number of contours used. |
u.e |
The values associated with the level sets |
G |
A vector which shows which of the level sets |
map |
Representation of the contour map with |
F |
The contour map function (if computed). |
M |
Contour avoiding sets (if |
P0/P1/P2 |
Calculated quality measures (if computed). |
P0bound/P1bound/P2bound |
Calculated upper bounds quality measures (if computed). |
meta |
A list containing various information about the calculation. |
David Bolin [email protected]
Bolin, D. and Lindgren, F. (2017) Quantifying the uncertainty of contour maps, Journal of Computational and Graphical Statistics, 26:3, 513-524.
Bolin, D. and Lindgren, F. (2018), Calculating Probabilistic Excursion Sets and Related Quantities Using excursions, Journal of Statistical Software, 86(5), 1–20.
contourmap(), contourmap.inla(), contourmap.colors()
n <- 100 Q <- Matrix(toeplitz(c(1, -0.5, rep(0, n - 2)))) mu <- seq(-5, 5, length = n) ## Sample the model 100 times (increase for better estimate) X <- mu + solve(chol(Q), matrix(rnorm(n = n * 100), nrow = n, ncol = 100)) lp <- contourmap.mc(X, n.levels = 2, compute = list(F = FALSE, measures = c("P1", "P2"))) # plot contourmap plot(lp$map) # display quality measures c(lp$P1, lp$P2)n <- 100 Q <- Matrix(toeplitz(c(1, -0.5, rep(0, n - 2)))) mu <- seq(-5, 5, length = n) ## Sample the model 100 times (increase for better estimate) X <- mu + solve(chol(Q), matrix(rnorm(n = n * 100), nrow = n, ncol = 100)) lp <- contourmap.mc(X, n.levels = 2, compute = list(F = FALSE, measures = c("P1", "P2"))) # plot contourmap plot(lp$map) # display quality measures c(lp$P1, lp$P2)
Loads the INLA package with requireNamespace("INLA", quietly = TRUE), and
optionally checks and sets the multicore num.threads INLA option.
exc_safe_inla(multicore = NULL, quietly = FALSE)exc_safe_inla(multicore = NULL, quietly = FALSE)
multicore |
logical; if |
quietly |
logical; if |
logical; TRUE if INLA was loaded safely, otherwise FALSE
## Not run: if (exc_safe_inla()) { # Run inla dependent calculations } ## End(Not run)## Not run: if (exc_safe_inla()) { # Run inla dependent calculations } ## End(Not run)
excursions is one of the main functions in the package with the same name.
For an introduction to the package, see excursions-package().
The function is used for calculating excursion sets, contour credible regions,
and contour avoiding sets for latent Gaussian models. Details on the function and the
package are given in the sections below.
excursions( alpha, u, mu, Q, type, n.iter = 10000, Q.chol, F.limit, vars, rho, reo, method = "EB", ind, max.size, verbose = 0, max.threads = 0, seed, prune.ind = FALSE )excursions( alpha, u, mu, Q, type, n.iter = 10000, Q.chol, F.limit, vars, rho, reo, method = "EB", ind, max.size, verbose = 0, max.threads = 0, seed, prune.ind = FALSE )
alpha |
Error probability for the excursion set. |
u |
Excursion or contour level. |
mu |
Expectation vector. |
Q |
Precision matrix. |
type |
Type of region:
|
n.iter |
Number or iterations in the MC sampler that is used for approximating probabilities. The default value is 10000. |
Q.chol |
The Cholesky factor of the precision matrix (optional). |
F.limit |
The limit value for the computation of the F function. F is set to NA for all nodes where F<1-F.limit. Default is F.limit = |
vars |
Precomputed marginal variances (optional). |
rho |
Marginal excursion probabilities (optional). For contour regions, provide |
reo |
Reordering (optional). |
method |
Method for handeling the latent Gaussian structure:
|
ind |
Indices of the nodes that should be analysed (optional). |
max.size |
Maximum number of nodes to include in the set of interest (optional). |
verbose |
Set to TRUE for verbose mode (optional). |
max.threads |
Decides the number of threads the program can use. Set to 0 for using the maximum number of threads allowed by the system (default). |
seed |
Random seed (optional). |
prune.ind |
If |
The estimation of the region is done using sequential importance sampling with
n.iter samples. The procedure requires computing the marginal variances of
the field, which should be supplied if available. If not, they are computed using
the Cholesky factor of the precision matrix. The cost of this step can therefore be
reduced by supplying the Cholesky factor if it is available.
The latent structure in the latent Gaussian model can be handled in several different
ways. The default strategy is the EB method, which is
exact for problems with Gaussian posterior distributions. For problems with
non-Gaussian posteriors, the QC method can be used for improved results. In order to use
the QC method, the true marginal excursion probabilities must be supplied using the
argument rho.
Other more
complicated methods for handling non-Gaussian posteriors must be implemented manually
unless INLA is used to fit the model. If the model is fitted using INLA,
the method excursions.inla can be used. See the Package section for further details
about the different options.
excursions returns an object of class "excurobj" with the following elements
E |
Excursion set, contour credible region, or contour avoiding set |
G |
Contour map set. |
M |
Contour avoiding set. |
F |
The excursion function corresponding to the set |
rho |
Marginal excursion probabilities |
mean |
The mean |
vars |
Marginal variances. |
meta |
A list containing various information about the calculation. |
David Bolin [email protected] and Finn Lindgren [email protected]
Bolin, D. and Lindgren, F. (2015) Excursion and contour uncertainty regions for latent Gaussian models, JRSS-series B, vol 77, no 1, pp 85-106.
Bolin, D. and Lindgren, F. (2018), Calculating Probabilistic Excursion Sets and Related Quantities Using excursions, Journal of Statistical Software, vol 86, no 1, pp 1-20.
excursions-package(), excursions.inla(), excursions.mc()
## Create a tridiagonal precision matrix n <- 21 Q.x <- sparseMatrix( i = c(1:n, 2:n), j = c(1:n, 1:(n - 1)), x = c(rep(1, n), rep(-0.1, n - 1)), dims = c(n, n), symmetric = TRUE ) ## Set the mean value function mu.x <- seq(-5, 5, length = n) ## calculate the level 0 positive excursion function res.x <- excursions( alpha = 1, u = 0, mu = mu.x, Q = Q.x, type = ">", verbose = 1, max.threads = 2 ) ## Plot the excursion function and the marginal excursion probabilities plot(res.x$F, type = "l", main = "Excursion function (black) and marginal probabilites (red)" ) lines(res.x$rho, col = 2)## Create a tridiagonal precision matrix n <- 21 Q.x <- sparseMatrix( i = c(1:n, 2:n), j = c(1:n, 1:(n - 1)), x = c(rep(1, n), rep(-0.1, n - 1)), dims = c(n, n), symmetric = TRUE ) ## Set the mean value function mu.x <- seq(-5, 5, length = n) ## calculate the level 0 positive excursion function res.x <- excursions( alpha = 1, u = 0, mu = mu.x, Q = Q.x, type = ">", verbose = 1, max.threads = 2 ) ## Plot the excursion function and the marginal excursion probabilities plot(res.x$F, type = "l", main = "Excursion function (black) and marginal probabilites (red)" ) lines(res.x$rho, col = 2)
Excursion sets and contour credible regions for latent Gaussian models calculated using the INLA method.
excursions.inla( result.inla, stack, name = NULL, tag = NULL, ind = NULL, method, alpha = 1, F.limit, u, u.link = FALSE, type, n.iter = 10000, verbose = 0, max.threads = 0, compressed = TRUE, seed = NULL, prune.ind = FALSE )excursions.inla( result.inla, stack, name = NULL, tag = NULL, ind = NULL, method, alpha = 1, F.limit, u, u.link = FALSE, type, n.iter = 10000, verbose = 0, max.threads = 0, compressed = TRUE, seed = NULL, prune.ind = FALSE )
result.inla |
Result object from INLA call. |
stack |
The stack object used in the INLA call. |
name |
The name of the component for which to do the calculation. This argument should only be used if a stack object is not provided, use the tag argument otherwise. |
tag |
The tag of the component in the stack for which to do the calculation. This argument should only be used if a stack object is provided, use the name argument otherwise. |
ind |
If only a part of a component should be used in the calculations, this argument specifies the indices for that part. |
method |
Method for handeling the latent Gaussian structure:
|
alpha |
Error probability for the excursion set of interest. The default value is 1. |
F.limit |
Error probability for when to stop the calculation of the
excursion function. The default value is |
u |
Excursion or contour level. |
u.link |
If u.link is TRUE, |
type |
Type of region:
|
n.iter |
Number or iterations in the MC sampler that is used for approximating probabilities. The default value is 10000. |
verbose |
Set to TRUE for verbose mode (optional). |
max.threads |
Decides the number of threads the program can use. Set to 0 for using the maximum number of threads allowed by the system (default). |
compressed |
If INLA is run in compressed mode and a part of the linear predictor is to be used, then only add the relevant part. Otherwise the entire linear predictor is added internally (default TRUE). |
seed |
Random seed (optional). |
prune.ind |
If |
The different methods for handling the latent Gaussian structure are
listed in order of accuracy and computational cost. The EB method is
the simplest and is based on a Gaussian approximation of the posterior of the
quantity of interest. The QC method uses the same Gaussian approximation
but improves the accuracy by modifying the limits in the integrals that are
computed in order to find the region. The other three methods are intended for
Bayesian models where the posterior distribution for the quantity of interest
is obtained by integrating over the parameters in the model. The NI
method approximates this integration in the same way as is done in INLA, and
the NIQC and iNIQC methods combine this apprximation with the
QC method for improved accuracy.
If the main purpose of the analysis is to construct excursion or contour sets
for low values of alpha, we recommend using QC for problems with
Gaussian likelihoods and NIQC for problems with non-Gaussian likelihoods.
The reason for this is that the more accurate methods also have higher
computational costs.
excursions.inla returns an object of class "excurobj" with the
following elements
E |
Excursion set, contour credible region, or contour avoiding set |
F |
The excursion function corresponding to the set |
G |
Contour map set. |
M |
Contour avoiding set. |
rho |
Marginal excursion probabilities |
mean |
Posterior mean |
vars |
Marginal variances |
meta |
A list containing various information about the calculation. |
This function requires the INLA package, which is not a CRAN
package. See https://www.r-inla.org/download-install for easy
installation instructions.
David Bolin [email protected] and Finn Lindgren [email protected]
Bolin, D. and Lindgren, F. (2015) Excursion and contour uncertainty regions for latent Gaussian models, JRSS-series B, vol 77, no 1, pp 85-106.
Bolin, D. and Lindgren, F. (2018), Calculating Probabilistic Excursion Sets and Related Quantities Using excursions, Journal of Statistical Software, vol 86, no 1, pp 1-20.
## In this example, we calculate the excursion function ## for a partially observed AR process. ## Not run: if (require.nowarnings("INLA")) { ## Sample the process: rho <- 0.9 tau <- 15 tau.e <- 1 n <- 100 x <- 1:n mu <- 10 * ((x < n / 2) * (x - n / 2) + (x >= n / 2) * (n / 2 - x) + n / 4) / n Q <- tau * sparseMatrix( i = c(1:n, 2:n), j = c(1:n, 1:(n - 1)), x = c(1, rep(1 + rho^2, n - 2), 1, rep(-rho, n - 1)), dims = c(n, n), symmetric = TRUE ) X <- mu + solve(chol(Q), rnorm(n)) ## measure the sampled process at n.obs random locations ## under Gaussian measurement noise. n.obs <- 50 obs.loc <- sample(1:n, n.obs) A <- sparseMatrix( i = 1:n.obs, j = obs.loc, x = rep(1, n.obs), dims = c(n.obs, n) ) Y <- as.vector(A %*% X + rnorm(n.obs) / sqrt(tau.e)) ## Estimate the parameters using INLA ef <- list(c(list(ar = x), list(cov = mu))) s.obs <- inla.stack(data = list(y = Y), A = list(A), effects = ef, tag = "obs") s.pre <- inla.stack(data = list(y = NA), A = list(1), effects = ef, tag = "pred") stack <- inla.stack(s.obs, s.pre) formula <- y ~ -1 + cov + f(ar, model = "ar1") result <- inla( formula = formula, family = "normal", data = inla.stack.data(stack), control.predictor = list(A = inla.stack.A(stack), compute = TRUE), control.compute = list( config = TRUE, return.marginals.predictor = TRUE ) ) ## calculate the level 0 positive excursion function res.qc <- excursions.inla(result, stack = stack, tag = "pred", alpha = 0.99, u = 0, method = "QC", type = ">", max.threads = 2 ) ## plot the excursion function and marginal probabilities plot(res.qc$rho, type = "l", main = "marginal probabilities (black) and excursion function (red)" ) lines(res.qc$F, col = 2) } ## End(Not run)## In this example, we calculate the excursion function ## for a partially observed AR process. ## Not run: if (require.nowarnings("INLA")) { ## Sample the process: rho <- 0.9 tau <- 15 tau.e <- 1 n <- 100 x <- 1:n mu <- 10 * ((x < n / 2) * (x - n / 2) + (x >= n / 2) * (n / 2 - x) + n / 4) / n Q <- tau * sparseMatrix( i = c(1:n, 2:n), j = c(1:n, 1:(n - 1)), x = c(1, rep(1 + rho^2, n - 2), 1, rep(-rho, n - 1)), dims = c(n, n), symmetric = TRUE ) X <- mu + solve(chol(Q), rnorm(n)) ## measure the sampled process at n.obs random locations ## under Gaussian measurement noise. n.obs <- 50 obs.loc <- sample(1:n, n.obs) A <- sparseMatrix( i = 1:n.obs, j = obs.loc, x = rep(1, n.obs), dims = c(n.obs, n) ) Y <- as.vector(A %*% X + rnorm(n.obs) / sqrt(tau.e)) ## Estimate the parameters using INLA ef <- list(c(list(ar = x), list(cov = mu))) s.obs <- inla.stack(data = list(y = Y), A = list(A), effects = ef, tag = "obs") s.pre <- inla.stack(data = list(y = NA), A = list(1), effects = ef, tag = "pred") stack <- inla.stack(s.obs, s.pre) formula <- y ~ -1 + cov + f(ar, model = "ar1") result <- inla( formula = formula, family = "normal", data = inla.stack.data(stack), control.predictor = list(A = inla.stack.A(stack), compute = TRUE), control.compute = list( config = TRUE, return.marginals.predictor = TRUE ) ) ## calculate the level 0 positive excursion function res.qc <- excursions.inla(result, stack = stack, tag = "pred", alpha = 0.99, u = 0, method = "QC", type = ">", max.threads = 2 ) ## plot the excursion function and marginal probabilities plot(res.qc$rho, type = "l", main = "marginal probabilities (black) and excursion function (red)" ) lines(res.qc$F, col = 2) } ## End(Not run)
excursions.mc is used for calculating excursion sets, contour credible
regions, and contour avoiding sets based on Monte Carlo samples of models.
excursions.mc( samples, alpha, u, type, rho, reo, ind, max.size, verbose = FALSE, prune.ind = FALSE )excursions.mc( samples, alpha, u, type, rho, reo, ind, max.size, verbose = FALSE, prune.ind = FALSE )
samples |
Matrix with model Monte Carlo samples. Each column contains a sample of the model. |
alpha |
Error probability for the excursion set. |
u |
Excursion or contour level. |
type |
Type of region:
|
rho |
Marginal excursion probabilities (optional). For contour regions,
provide |
reo |
Reordering (optional). |
ind |
Indices of the nodes that should be analysed (optional). |
max.size |
Maximum number of nodes to include in the set of interest (optional). |
verbose |
Set to TRUE for verbose mode (optional). |
prune.ind |
If |
excursions.mc returns an object of class "excurobj" with the
following elements
E |
Excursion set, contour credible region, or contour avoiding set. |
G |
Contour map set. |
M |
Contour avoiding set. |
F |
The excursion function corresponding to the set |
rho |
Marginal excursion probabilities |
mean |
The mean |
vars |
Marginal variances. |
meta |
A list containing various information about the calculation. |
David Bolin [email protected] and Finn Lindgren [email protected]
Bolin, D. and Lindgren, F. (2015) Excursion and contour uncertainty regions for latent Gaussian models, JRSS-series B, vol 77, no 1, pp 85-106.
Bolin, D. and Lindgren, F. (2018), Calculating Probabilistic Excursion Sets and Related Quantities Using excursions, Journal of Statistical Software, vol 86, no 1, pp 1-20.
excursions(), excursions.inla()
## Create mean and a tridiagonal precision matrix n <- 101 mu.x <- seq(-5, 5, length = n) Q.x <- Matrix(toeplitz(c(1, -0.1, rep(0, n - 2)))) ## Sample the model 100 times (increase for better estimate) X <- mu.x + solve(chol(Q.x), matrix(rnorm(n = n * 1000), nrow = n, ncol = 1000)) ## calculate the positive excursion function res.x <- excursions.mc(X, alpha = 0.05, type = ">", u = 0) ## Plot the excursion function and the marginal excursion probabilities plot(res.x$F, type = "l", main = "Excursion function (black) and marginal probabilites (red)" ) lines(res.x$rho, col = 2)## Create mean and a tridiagonal precision matrix n <- 101 mu.x <- seq(-5, 5, length = n) Q.x <- Matrix(toeplitz(c(1, -0.1, rep(0, n - 2)))) ## Sample the model 100 times (increase for better estimate) X <- mu.x + solve(chol(Q.x), matrix(rnorm(n = n * 1000), nrow = n, ncol = 1000)) ## calculate the positive excursion function res.x <- excursions.mc(X, alpha = 0.05, type = ">", u = 0) ## Plot the excursion function and the marginal excursion probabilities plot(res.x$F, type = "l", main = "Excursion function (black) and marginal probabilites (red)" ) lines(res.x$rho, col = 2)
excursions.variances calculates the diagonal of the inverse of a sparse
symmetric positive definite matrix Q.
excursions.variances(L, Q, max.threads = 0)excursions.variances(L, Q, max.threads = 0)
L |
Cholesky factor of precision matrix. |
Q |
Precision matrix. |
max.threads |
Decides the number of threads the program can use. Set to 0 for using the maximum number of threads allowed by the system (default). |
The method for calculating the
diagonal requires the Cholesky factor, L, of Q, which should be supplied if
available. If Q is provided, the cholesky factor is
calculated and the variances are then returned in the same ordering as Q.
If L is provided, the variances are returned in the same ordering as L,
even if L@invpivot exists.
A vector with the variances.
David Bolin [email protected]
## Create a tridiagonal precision matrix n <- 21 Q <- Matrix(toeplitz(c(1, -0.1, rep(0, n - 2)))) v2 <- excursions.variances(Q = Q, max.threads = 2) ## var2 should be the same as: v1 <- diag(solve(Q))## Create a tridiagonal precision matrix n <- 21 Q <- Matrix(toeplitz(c(1, -0.1, rep(0, n - 2)))) v2 <- excursions.variances(Q = Q, max.threads = 2) ## var2 should be the same as: v1 <- diag(solve(Q))
gaussint is used for calculating -dimensional Gaussian integrals
A limit value can be used to stop the integration if the sequential
estimate goes below the limit, which can result in substantial computational
savings in cases when one only is interested in testing if the integral is above
the limit value. The integral is calculated sequentially, and estimates for
all subintegrals are also returned.
gaussint( mu, Q.chol, Q, a, b, lim = 0, n.iter = 10000, ind, use.reordering = c("natural", "sparsity", "limits"), max.size, max.threads = 0, seed )gaussint( mu, Q.chol, Q, a, b, lim = 0, n.iter = 10000, ind, use.reordering = c("natural", "sparsity", "limits"), max.size, max.threads = 0, seed )
mu |
Expectation vector for the Gaussian distribution. |
Q.chol |
The Cholesky factor of the precision matrix (optional). |
Q |
Precision matrix for the Gaussian distribution. If Q is supplied but not Q.chol, the cholesky factor is computed before integrating. |
a |
Lower limit in integral. |
b |
Upper limit in integral. |
lim |
If this argument is used, the integration is stopped and 0 is returned
if the estimated value goes below |
n.iter |
Number or iterations in the MC sampler that is used for approximating probabilities. The default value is 10000. |
ind |
Indices of the nodes that should be analyzed (optional). |
use.reordering |
Determines what reordering to use:
|
max.size |
The largest number of sub-integrals to compute. Default is the total dimension of the distribution. |
max.threads |
Decides the number of threads the program can use. Set to 0 for using the maximum number of threads allowed by the system (default). |
seed |
The random seed to use (optional). |
The function uses sequential importance sampling to estimate the
Gaussian integral, and returns all computed sub-integrals. This means that if, for
example, the function is used to compute for an n-dimensional Gaussian
variable , then all integrals for are
computed.
If one is only interested in whether or not, then one can
stop the integration as soon as . This can save a lot of
computation time if for much smaller than
. This limit value is specified by the lim argument.
Which reordering to use depends on what the purpose of the calculation is and what
the integration limits are. However, in general the limits reordering is typically
most appropriate since this combines sparisty (which improves accuracy and reduces
computational cost) with automatic handling of dimensions with limits a=-Inf and
b=Inf, which do not affect the probability but affect the computation time
if they are not handled separately.
A list with elements
P |
Value of the integral. |
E |
Estimated error of the P estimate. |
Pv |
A vector with the estimates of all sub-integrals. |
Ev |
A vector with the estimated errors of the Pv estimates. |
David Bolin [email protected]
Bolin, D. and Lindgren, F. (2015) Excursion and contour uncertainty regions for latent Gaussian models, JRSS-series B, vol 77, no 1, pp 85-106.
Bolin, D. and Lindgren, F. (2018), Calculating Probabilistic Excursion Sets and Related Quantities Using excursions, Journal of Statistical Software, vol 86, no 1, pp 1-20.
## Create mean and a tridiagonal precision matrix n <- 11 mu.x <- seq(-5, 5, length = n) Q.x <- Matrix(toeplitz(c(1, -0.1, rep(0, n - 2)))) ## Calculate the probability that the variable is between mu-3 and mu+3 prob <- gaussint(mu = mu.x, Q = Q.x, a = mu.x - 3, b = mu.x + 3, max.threads = 2) prob$P## Create mean and a tridiagonal precision matrix n <- 11 mu.x <- seq(-5, 5, length = n) Q.x <- Matrix(toeplitz(c(1, -0.1, rep(0, n - 2)))) ## Calculate the probability that the variable is between mu-3 and mu+3 prob <- gaussint(mu = mu.x, Q = Q.x, a = mu.x - 3, b = mu.x + 3, max.threads = 2) prob$P
Turn off all warnings for require(), to allow clean completion of examples that require unavailable Suggested packages.
require.nowarnings(package, lib.loc = NULL, character.only = FALSE)require.nowarnings(package, lib.loc = NULL, character.only = FALSE)
package |
The name of a package, given as a character string. |
lib.loc |
a character vector describing the location of R library trees
to search through, or |
character.only |
a logical indicating whether |
require(package) acts the same as
require(package, quietly = TRUE) but with warnings turned off.
In particular, no warning or error is given if the package is unavailable.
Most cases should use requireNamespace(package, quietly = TRUE) instead,
which doesn't produce warnings.
require.nowarnings returns (invisibly) TRUE if it succeeds, otherwise FALSE
## This should produce no output: if (require.nowarnings(nonexistent)) { message("Package loaded successfully") }## This should produce no output: if (require.nowarnings(nonexistent)) { message("Package loaded successfully") }
simconf is used for calculating simultaneous confidence regions for
Gaussian models . The function returns upper and lower bounds
and such that .
simconf( alpha, mu, Q, n.iter = 10000, Q.chol, vars, ind = NULL, verbose = 0, max.threads = 0, seed = NULL )simconf( alpha, mu, Q, n.iter = 10000, Q.chol, vars, ind = NULL, verbose = 0, max.threads = 0, seed = NULL )
alpha |
Error probability for the region. |
mu |
Expectation vector for the Gaussian distribution. |
Q |
Precision matrix for the Gaussian distribution. |
n.iter |
Number or iterations in the MC sampler that is used for approximating probabilities. The default value is 10000. |
Q.chol |
The Cholesky factor of the precision matrix (optional). |
vars |
Precomputed marginal variances (optional). |
ind |
Indices of the nodes that should be analyzed (optional). |
verbose |
Set to TRUE for verbose mode (optional). |
max.threads |
Decides the number of threads the program can use. Set to 0 for using the maximum number of threads allowed by the system (default). |
seed |
Random seed (optional). |
The pointwise confidence bands are based on the marginal quantiles,
meaning that a.marignal is a vector where the ith element equals
and b.marginal is a vector where the ith element
equals , where is the expected value
of the and is the -quantile of .
The simultaneous confidence band is defined by the lower limit vector a and
the upper limit vector b, where and
, where is a constant computed such
that .
An object of class "excurobj" with elements
a |
The lower bound. |
b |
The upper bound. |
a.marginal |
The lower bound for pointwise confidence bands. |
b.marginal |
The upper bound for pointwise confidence bands. |
David Bolin [email protected] and Finn Lindgren [email protected]
Bolin et al. (2015) Statistical prediction of global sea level from global temperature, Statistica Sinica, vol 25, pp 351-367.
Bolin, D. and Lindgren, F. (2018), Calculating Probabilistic Excursion Sets and Related Quantities Using excursions, Journal of Statistical Software, vol 86, no 1, pp 1-20.
simconf.inla(), simconf.mc(), simconf.mixture()
## Create mean and a tridiagonal precision matrix n <- 11 mu.x <- seq(-5, 5, length = n) Q.x <- Matrix(toeplitz(c(1, -0.1, rep(0, n - 2)))) ## calculate the confidence region conf <- simconf(0.05, mu.x, Q.x, max.threads = 2) ## Plot the region plot(mu.x, type = "l", ylim = c(-10, 10), main = "Mean (black) and confidence region (red)" ) lines(conf$a, col = 2) lines(conf$b, col = 2)## Create mean and a tridiagonal precision matrix n <- 11 mu.x <- seq(-5, 5, length = n) Q.x <- Matrix(toeplitz(c(1, -0.1, rep(0, n - 2)))) ## calculate the confidence region conf <- simconf(0.05, mu.x, Q.x, max.threads = 2) ## Plot the region plot(mu.x, type = "l", ylim = c(-10, 10), main = "Mean (black) and confidence region (red)" ) lines(conf$a, col = 2) lines(conf$b, col = 2)
simconf.inla is used for calculating simultaneous confidence regions
for latent Gaussian models estimated using INLA.
simconf.inla( result.inla, stack, name = NULL, tag = NULL, ind = NULL, alpha, method = "NI", n.iter = 10000, verbose = FALSE, link = FALSE, max.threads = 0, compressed = TRUE, seed = NULL, inla.sample = TRUE )simconf.inla( result.inla, stack, name = NULL, tag = NULL, ind = NULL, alpha, method = "NI", n.iter = 10000, verbose = FALSE, link = FALSE, max.threads = 0, compressed = TRUE, seed = NULL, inla.sample = TRUE )
result.inla |
Result object from INLA call. |
stack |
The stack object used in the INLA call. |
name |
The name of the component for which to do the calculation. This argument should only be used if a stack object is not provided, use the tag argument otherwise. |
tag |
The tag of the component in the stack for which to do the calculation. This argument should only be used if a stack object is provided, use the name argument otherwise. |
ind |
If only a part of a component should be used in the calculations, this argument specifies the indices for that part. |
alpha |
Error probability for the region. |
method |
Method for handling the latent Gaussian structure:
|
n.iter |
Number or iterations in the MC sampler that is used for approximating probabilities. The default value is 10000. |
verbose |
Set to TRUE for verbose mode (optional). |
link |
Transform output to the scale of the data using the link function as defined in the model estimated with INLA (default FALSE). |
max.threads |
Decides the number of threads the program can use. Set to 0 for using the maximum number of threads allowed by the system (default). |
compressed |
If INLA is run in compressed mode and a part of the linear predictor is to be used, then only add the relevant part. Otherwise the entire linear predictor is added internally (default TRUE). |
seed |
Random seed (optional). |
inla.sample |
Set to TRUE if inla.posterior.sample should be used for the MC integration. |
See simconf() for details.
An object of class "excurobj" with elements
a |
The lower bound. |
b |
The upper bound. |
a.marginal |
The lower bound for pointwise confidence bands. |
b.marginal |
The upper bound for pointwise confidence bands. |
This function requires the INLA package, which is not a CRAN package.
See https://www.r-inla.org/download-install for easy installation instructions.
David Bolin [email protected]
Bolin et al. (2015) Statistical prediction of global sea level from global temperature, Statistica Sinica, vol 25, pp 351-367.
Bolin, D. and Lindgren, F. (2018), Calculating Probabilistic Excursion Sets and Related Quantities Using excursions, Journal of Statistical Software, vol 86, no 1, pp 1-20.
simconf(), simconf.mc(), simconf.mixture()
## Not run: if (require.nowarnings("INLA")) { n <- 10 x <- seq(0, 6, length.out = n) y <- sin(x) + rnorm(n) mu <- 1:n result <- inla(y ~ 1 + f(mu, model = "rw2"), data = list(y = y, mu = mu), verbose = FALSE, control.compute = list( config = TRUE, return.marginals.predictor = TRUE ), num.threads = "1:1" ) res <- simconf.inla( result, name = "mu", alpha = 0.05, max.threads = 1, num.threads = "1:1") plot(result$summary.random$mu$mean, ylim = c(-2, 2)) lines(res$a) lines(res$b) lines(res$a.marginal, col = "2") lines(res$b.marginal, col = "2") } ## End(Not run)## Not run: if (require.nowarnings("INLA")) { n <- 10 x <- seq(0, 6, length.out = n) y <- sin(x) + rnorm(n) mu <- 1:n result <- inla(y ~ 1 + f(mu, model = "rw2"), data = list(y = y, mu = mu), verbose = FALSE, control.compute = list( config = TRUE, return.marginals.predictor = TRUE ), num.threads = "1:1" ) res <- simconf.inla( result, name = "mu", alpha = 0.05, max.threads = 1, num.threads = "1:1") plot(result$summary.random$mu$mean, ylim = c(-2, 2)) lines(res$a) lines(res$b) lines(res$a.marginal, col = "2") lines(res$b.marginal, col = "2") } ## End(Not run)
simconf.mc is used for calculating simultaneous confidence regions based
on Monte Carlo samples. The function returns upper and lower bounds and
such that .
simconf.mc(samples, alpha, ind, verbose = FALSE)simconf.mc(samples, alpha, ind, verbose = FALSE)
samples |
Matrix with model Monte Carlo samples. Each column contains a sample of the model. |
alpha |
Error probability for the region. |
ind |
Indices of the nodes that should be analyzed (optional). |
verbose |
Set to TRUE for verbose mode (optional). |
See simconf() for details.
An object of class "excurobj" with elements
a |
The lower bound. |
b |
The upper bound. |
a.marginal |
The lower bound for pointwise confidence bands. |
b.marginal |
The upper bound for pointwise confidence bands. |
David Bolin [email protected]
## Create mean and a tridiagonal precision matrix n <- 11 mu.x <- seq(-5, 5, length = n) Q.x <- Matrix(toeplitz(c(1, -0.1, rep(0, n - 2)))) ## Sample the model 100 times (increase for better estimate) X <- mu.x + solve(chol(Q.x), matrix(rnorm(n = n * 100), nrow = n, ncol = 100)) ## calculate the confidence region conf <- simconf.mc(X, 0.2) ## Plot the region plot(mu.x, type = "l", ylim = c(-10, 10), main = "Mean (black) and confidence region (red)" ) lines(conf$a, col = 2) lines(conf$b, col = 2)## Create mean and a tridiagonal precision matrix n <- 11 mu.x <- seq(-5, 5, length = n) Q.x <- Matrix(toeplitz(c(1, -0.1, rep(0, n - 2)))) ## Sample the model 100 times (increase for better estimate) X <- mu.x + solve(chol(Q.x), matrix(rnorm(n = n * 100), nrow = n, ncol = 100)) ## calculate the confidence region conf <- simconf.mc(X, 0.2) ## Plot the region plot(mu.x, type = "l", ylim = c(-10, 10), main = "Mean (black) and confidence region (red)" ) lines(conf$a, col = 2) lines(conf$b, col = 2)
simconf.mixture is used for calculating simultaneous confidence regions
for Gaussian mixture models. The distribution for the process is assumed to be
The function returns upper and lower bounds and such that
.
simconf.mixture( alpha, mu, Q, w, ind, n.iter = 10000, vars, verbose = FALSE, max.threads = 0, seed = NULL, mix.samp = TRUE )simconf.mixture( alpha, mu, Q, w, ind, n.iter = 10000, vars, verbose = FALSE, max.threads = 0, seed = NULL, mix.samp = TRUE )
alpha |
Error probability for the region. |
mu |
A list with the |
Q |
A list with the |
w |
A vector with the weights for each class in the mixture. |
ind |
Indices of the nodes that should be analyzed (optional). |
n.iter |
Number or iterations in the MC sampler that is used for approximating probabilities. The default value is 10000. |
vars |
A list with precomputed marginal variances for each class (optional). |
verbose |
Set to TRUE for verbose mode (optional). |
max.threads |
Decides the number of threads the program can use. Set to 0 for using the maximum number of threads allowed by the system (default). |
seed |
Random seed (optional). |
mix.samp |
If TRUE, the MC integration is done by directly sampling the mixture, otherwise sequential integration is used. |
See simconf() for details.
An object of class "excurobj" with elements
a |
The lower bound. |
b |
The upper bound. |
a.marginal |
The lower bound for pointwise confidence bands. |
b.marginal |
The upper bound for pointwise confidence bands. |
David Bolin [email protected]
Bolin et al. (2015) Statistical prediction of global sea level from global temperature, Statistica Sinica, vol 25, pp 351-367.
Bolin, D. and Lindgren, F. (2018), Calculating Probabilistic Excursion Sets and Related Quantities Using excursions, Journal of Statistical Software, vol 86, no 1, pp 1-20.
simconf(), simconf.inla(), simconf.mc()
n <- 11 K <- 3 mu <- Q <- list() for (k in 1:K) { mu[[k]] <- k * 0.1 + seq(-5, 5, length = n) Q[[k]] <- Matrix(toeplitz(c(1, -0.1, rep(0, n - 2)))) } ## calculate the confidence region conf <- simconf.mixture(0.05, mu, Q, w = rep(1 / 3, 3), max.threads = 2) ## Plot the region plot(mu[[1]], type = "l") lines(mu[[2]]) lines(mu[[3]]) lines(conf$a, col = 2) lines(conf$b, col = 2)n <- 11 K <- 3 mu <- Q <- list() for (k in 1:K) { mu[[k]] <- k * 0.1 + seq(-5, 5, length = n) Q[[k]] <- Matrix(toeplitz(c(1, -0.1, rep(0, n - 2)))) } ## calculate the confidence region conf <- simconf.mixture(0.05, mu, Q, w = rep(1 / 3, 3), max.threads = 2) ## Plot the region plot(mu[[1]], type = "l") lines(mu[[2]]) lines(mu[[3]]) lines(conf$a, col = 2) lines(conf$b, col = 2)
Extracts a part of a grid.
submesh.grid(z, grid = NULL)submesh.grid(z, grid = NULL)
z |
A matrix with values indicating which nodes that should be present in the submesh. |
grid |
A list with locations and dimensions of the grid. |
An fm_mesh_2d object.
Finn Lindgren [email protected]
## Not run: if (require("fmesher")) { nxy <- 40 x <- seq(from = 0, to = 4, length.out = nxy) lattice <- fm_lattice_2d(x = x, y = x) mesh <- fm_rcdt_2d_inla(lattice = lattice, extend = FALSE, refine = FALSE) # extract a part of the mesh inside a circle xy.in <- rowSums((mesh$loc[, 1:2] - 2)^2) < 1 submesh <- submesh.grid( matrix(xy.in, nxy, nxy), list(loc = mesh$loc, dim = c(nxy, nxy)) ) plot(mesh$loc[, 1:2]) lines(2 + cos(seq(0, 2 * pi, length.out = 100)), 2 + sin(seq(0, 2 * pi, length.out = 100))) plot(submesh, add = TRUE) points(mesh$loc[xy.in, 1:2], col = "2") } ## End(Not run)## Not run: if (require("fmesher")) { nxy <- 40 x <- seq(from = 0, to = 4, length.out = nxy) lattice <- fm_lattice_2d(x = x, y = x) mesh <- fm_rcdt_2d_inla(lattice = lattice, extend = FALSE, refine = FALSE) # extract a part of the mesh inside a circle xy.in <- rowSums((mesh$loc[, 1:2] - 2)^2) < 1 submesh <- submesh.grid( matrix(xy.in, nxy, nxy), list(loc = mesh$loc, dim = c(nxy, nxy)) ) plot(mesh$loc[, 1:2]) lines(2 + cos(seq(0, 2 * pi, length.out = 100)), 2 + sin(seq(0, 2 * pi, length.out = 100))) plot(submesh, add = TRUE) points(mesh$loc[xy.in, 1:2], col = "2") } ## End(Not run)
Extracts a part of a mesh
submesh.mesh(z, mesh)submesh.mesh(z, mesh)
z |
A matrix with values indicating which nodes that should be present in the submesh. |
mesh |
An |
An fm_mesh_2d object.
Finn Lindgren [email protected]
## Not run: if (require(fmesher)) { nxy <- 30 x <- seq(from = 0, to = 4, length.out = nxy) lattice <- fm_lattice_2d(x = x, y = x) mesh <- fm_mesh_2d_inla(lattice = lattice, extend = FALSE, refine = FALSE) # extract a part of the mesh inside a circle xy.in <- rowSums((mesh$loc[, 1:2] - 2)^2) < 1 submesh <- excursions:::submesh.mesh(matrix(xy.in, nxy, nxy), mesh) plot(mesh$loc[, 1:2]) lines(2 + cos(seq(0, 2 * pi, length.out = 100)), 2 + sin(seq(0, 2 * pi, length.out = 100))) plot(submesh, add = TRUE) points(mesh$loc[xy.in, 1:2], col = "2") } ## End(Not run)## Not run: if (require(fmesher)) { nxy <- 30 x <- seq(from = 0, to = 4, length.out = nxy) lattice <- fm_lattice_2d(x = x, y = x) mesh <- fm_mesh_2d_inla(lattice = lattice, extend = FALSE, refine = FALSE) # extract a part of the mesh inside a circle xy.in <- rowSums((mesh$loc[, 1:2] - 2)^2) < 1 submesh <- excursions:::submesh.mesh(matrix(xy.in, nxy, nxy), mesh) plot(mesh$loc[, 1:2]) lines(2 + cos(seq(0, 2 * pi, length.out = 100)), 2 + sin(seq(0, 2 * pi, length.out = 100))) plot(submesh, add = TRUE) points(mesh$loc[xy.in, 1:2], col = "2") } ## End(Not run)
Summary method for class "excurobj"
## S3 method for class 'excurobj' summary(object, ...) ## S3 method for class 'summary.excurobj' print(x, ...) ## S3 method for class 'excurobj' print(x, ...)## S3 method for class 'excurobj' summary(object, ...) ## S3 method for class 'summary.excurobj' print(x, ...) ## S3 method for class 'excurobj' print(x, ...)
object |
an object of class "excurobj", usually, a result of a call
to |
... |
further arguments passed to or from other methods. |
x |
an object of class "summary.excurobj", usually, a result of a call
to |
Calculates contour curves and/or regions between them, for functions defined on a triangulation
tricontour( x, z, nlevels = 10, levels = pretty(range(z, na.rm = TRUE), nlevels), ... ) ## S3 method for class 'fm_mesh_2d' tricontour( x, z, nlevels = 10, levels = pretty(range(z, na.rm = TRUE), nlevels), ... ) ## S3 method for class 'matrix' tricontour( x, z, nlevels = 10, levels = pretty(range(z, na.rm = TRUE), nlevels), loc, ... ) ## S3 method for class 'list' tricontour( x, z, nlevels = 10, levels = pretty(range(z, na.rm = TRUE), nlevels), loc, type = c("+", "-"), tol = 1e-07, ... ) tricontourmap( x, z, nlevels = 10, levels = pretty(range(z, na.rm = TRUE), nlevels), ... ) ## S3 method for class 'fm_mesh_2d' tricontourmap( x, z, nlevels = 10, levels = pretty(range(z, na.rm = TRUE), nlevels), ... ) ## S3 method for class 'matrix' tricontourmap( x, z, nlevels = 10, levels = pretty(range(z, na.rm = TRUE), nlevels), loc, ... ) ## S3 method for class 'list' tricontourmap( x, z, nlevels = 10, levels = pretty(range(z, na.rm = TRUE), nlevels), loc, type = c("+", "-"), tol = 1e-07, output = c("sp", "fm", "inla.mesh.segment"), ... )tricontour( x, z, nlevels = 10, levels = pretty(range(z, na.rm = TRUE), nlevels), ... ) ## S3 method for class 'fm_mesh_2d' tricontour( x, z, nlevels = 10, levels = pretty(range(z, na.rm = TRUE), nlevels), ... ) ## S3 method for class 'matrix' tricontour( x, z, nlevels = 10, levels = pretty(range(z, na.rm = TRUE), nlevels), loc, ... ) ## S3 method for class 'list' tricontour( x, z, nlevels = 10, levels = pretty(range(z, na.rm = TRUE), nlevels), loc, type = c("+", "-"), tol = 1e-07, ... ) tricontourmap( x, z, nlevels = 10, levels = pretty(range(z, na.rm = TRUE), nlevels), ... ) ## S3 method for class 'fm_mesh_2d' tricontourmap( x, z, nlevels = 10, levels = pretty(range(z, na.rm = TRUE), nlevels), ... ) ## S3 method for class 'matrix' tricontourmap( x, z, nlevels = 10, levels = pretty(range(z, na.rm = TRUE), nlevels), loc, ... ) ## S3 method for class 'list' tricontourmap( x, z, nlevels = 10, levels = pretty(range(z, na.rm = TRUE), nlevels), loc, type = c("+", "-"), tol = 1e-07, output = c("sp", "fm", "inla.mesh.segment"), ... )
x |
An object generated by a call to |
z |
A vector containing the values to be contoured
( |
nlevels |
Number of contour levels desired, if and only if
|
levels |
Numeric vector of levels at which to calculate contour lines. |
... |
Additional arguments passed to the other methods. |
loc |
coordinate matrix, to be supplied when |
type |
|
tol |
tolerance for determining if the value at a vertex lies on a level. |
output |
The format of the generated output. Implemented options
are |
For tricontour, a list with some of the fields that
fm_segm objects have:
loc |
A coordinate matrix |
idx |
Contour segment indices, as a 2-column matrix, each row indexing a single segment |
grp |
A vector of group labels. Each segment has a label, in
|
For tricontourmap, a list:
contour |
A list of |
map |
A list of |
Finn Lindgren [email protected]
## Not run: if (require("fmesher") && require("sp")) { ## Generate mesh and SPDE model n.lattice <- 20 # increase for more interesting, but slower, examples x <- seq(from = 0, to = 10, length.out = n.lattice) lattice <- fm_lattice_2d(x = x, y = x) mesh <- fm_rcdt_2d_inla(lattice = lattice, extend = FALSE, refine = FALSE) ## Generate an artificial sample sigma2.e <- 0.1 n.obs <- 1000 obs.loc <- cbind( runif(n.obs) * diff(range(x)) + min(x), runif(n.obs) * diff(range(x)) + min(x) ) Q <- fm_matern_precision(mesh, alpha = 2, rho = 3, sigma = 1) x <- fm_sample(n = 1, Q = Q) A <- fm_basis(mesh, loc = obs.loc) Y <- as.vector(A %*% x + rnorm(n.obs) * sqrt(sigma2.e)) ## Calculate posterior Q.post <- (Q + (t(A) %*% A) / sigma2.e) mu.post <- as.vector(solve(Q.post, (t(A) %*% Y) / sigma2.e)) ## Calculate continuous contours tric <- tricontour(mesh, z = mu.post, levels = as.vector(quantile(x, c(0.25, 0.75))) ) ## Discrete domain contours map <- contourmap( n.levels = 2, mu = mu.post, Q = Q.post, alpha = 0.1, compute = list(F = FALSE), max.threads = 1 ) ## Calculate continuous contour map setsc <- tricontourmap(mesh, z = mu.post, levels = as.vector(quantile(x, c(0.25, 0.75))) ) ## Plot the results reo <- mesh$idx$lattice idx.setsc <- setdiff(names(setsc$map), "-1") cols2 <- contourmap.colors(map, col = heat.colors(100, 0.5, rev = TRUE), credible.col = grey(0.5, 0) ) names(cols2) <- as.character(-1:2) par(mfrow = c(1, 2)) image(matrix(mu.post[reo], n.lattice, n.lattice), main = "mean", axes = FALSE, asp = 1 ) plot(setsc$map[idx.setsc], col = cols2[idx.setsc]) par(mfrow = c(1, 1)) } ## End(Not run)## Not run: if (require("fmesher") && require("sp")) { ## Generate mesh and SPDE model n.lattice <- 20 # increase for more interesting, but slower, examples x <- seq(from = 0, to = 10, length.out = n.lattice) lattice <- fm_lattice_2d(x = x, y = x) mesh <- fm_rcdt_2d_inla(lattice = lattice, extend = FALSE, refine = FALSE) ## Generate an artificial sample sigma2.e <- 0.1 n.obs <- 1000 obs.loc <- cbind( runif(n.obs) * diff(range(x)) + min(x), runif(n.obs) * diff(range(x)) + min(x) ) Q <- fm_matern_precision(mesh, alpha = 2, rho = 3, sigma = 1) x <- fm_sample(n = 1, Q = Q) A <- fm_basis(mesh, loc = obs.loc) Y <- as.vector(A %*% x + rnorm(n.obs) * sqrt(sigma2.e)) ## Calculate posterior Q.post <- (Q + (t(A) %*% A) / sigma2.e) mu.post <- as.vector(solve(Q.post, (t(A) %*% Y) / sigma2.e)) ## Calculate continuous contours tric <- tricontour(mesh, z = mu.post, levels = as.vector(quantile(x, c(0.25, 0.75))) ) ## Discrete domain contours map <- contourmap( n.levels = 2, mu = mu.post, Q = Q.post, alpha = 0.1, compute = list(F = FALSE), max.threads = 1 ) ## Calculate continuous contour map setsc <- tricontourmap(mesh, z = mu.post, levels = as.vector(quantile(x, c(0.25, 0.75))) ) ## Plot the results reo <- mesh$idx$lattice idx.setsc <- setdiff(names(setsc$map), "-1") cols2 <- contourmap.colors(map, col = heat.colors(100, 0.5, rev = TRUE), credible.col = grey(0.5, 0) ) names(cols2) <- as.character(-1:2) par(mfrow = c(1, 2)) image(matrix(mu.post[reo], n.lattice, n.lattice), main = "mean", axes = FALSE, asp = 1 ) plot(setsc$map[idx.setsc], col = cols2[idx.setsc]) par(mfrow = c(1, 1)) } ## End(Not run)