| Title: | Robust Statistics: Theory and Methods |
|---|---|
| Description: | Companion package for the book: "Robust Statistics: Theory and Methods, second edition", <http://www.wiley.com/go/maronna/robust>. This package contains code that implements the robust estimators discussed in the recent second edition of the book above, as well as the scripts reproducing all the examples in the book. |
| Authors: | Matias Salibian-Barrera [cre], Victor Yohai [aut], Ricardo Maronna [aut], Doug Martin [aut], Gregory Brownson [aut] (ShinyUI), Kjell Konis [aut], Kjell Konis [cph] (erfi), Christophe Croux [ctb] (WBYlogreg, BYlogreg), Gentiane Haesbroeck [ctb] (WBYlogreg, BYlogreg), Martin Maechler [cph] (lmrob.fit, lmrob..M..fit, lmrob.S), Manuel Koller [cph] (lmrob.fit, .vcov.avar1, lmrob.S, lmrob.lar), Matias Salibian-Barrera [aut] |
| Maintainer: | Matias Salibian-Barrera <[email protected]> |
| License: | GPL (>= 3) |
| Version: | 1.0.11 |
| Built: | 2024-11-15 06:22:50 UTC |
| Source: | https://github.com/msalibian/robstattm |
This data set contains physicochemical characteristics of 44 aliphatic alcohols. The aim of the experiment was the prediction of the solubility on the basis of molecular descriptors.
data(alcohol)data(alcohol)
An object of class "data.frame".
Format: 44 cases and 7 continuous variables. The columns are: 1. SAG=solvent accessible surface-bounded molecular volume 2. V=volume 3. log PC (PC=octanol–water partitions coefficient) 4. P=polarizability 5. RM=molar refractivity 6. Mass 7. log(Solubility) (response)
Romanelli, G.P., Martino, C.M. and Castro, E.A. (2001), Modeling the solubility of aliphatic alcohols via molecular descriptors, Journal of the Chemical Society of Pakistan, 23, 195-199.
data(alcohol)data(alcohol)
Each row of the data set is a set of 90 measurements at a river in some place in Europe. There are 11 predictors. The response is the logarithm of the abundance of a certain class of algae. Description: The columns are: 1. season, categorical (1,2,3,4 for winter, spring, summer and autumn) 2. river size (categorical) (1,2,3 for small, medium and large) 3. fluid velocity (categorical) (1,2,3 for low, medium and high) 4-11 (numerci): content of nitrogen in the form of nitrates, nitrites and ammonia, and other chemical compounds. Col. 12 ia the response: abundance of a type of algae (type 6 in the complete file). For simplicity we deleted the rows with missing values and took the logarithm of the response.
data(algae)data(algae)
An object of class "data.frame".
Format 90 rows, 12 columns (3 categorical, 9 numeric)
Hettich, S. and Bay, S.D. (1999), The UCI KDD Archive http://kdd.ics.uci.edu. Irvine, CA: University of California, Department of Information and Computer Science.
References go here.
data(algae)data(algae)
Two biochemical measurements on 12 men with similar weights.
data(biochem)data(biochem)
An object of class "data.frame".
Format: Numeric, 12 rows, two columns
Seber, G.A.F. (1984), Multivariate Observations. New York: John Wiley.
data(biochem)data(biochem)
This function computes the tuning constant that yields an MM-regression estimator with a desired asymptotic efficiency when computed with a rho function in the corresponding family. The output of this function can be passed to the functions lmrobdet.control, scaleM and rho.
bisquare(e)bisquare(e)
e |
the desired efficiency of the corresponding regression estimator for Gaussian errors |
A length-1 vector with the corresponding tuning constant.
Kjell Konis
# Tuning parameters for an 85%-efficient M-estimator at a Gaussian model bisquare(.85)# Tuning parameters for an 85%-efficient M-estimator at a Gaussian model bisquare(.85)
Patients suffering from simple or complex partial seizures were randomized to receive either the antiepileptic drug progabide or a placebo. At each of four successive post randomization clinic visits, the number of seizures occuring over the previous two weeks was reported.
data(breslow.dat)data(breslow.dat)
An object of class "data.frame".
Description: A data frame with 59 observations on the
following 12 variables: ID: an integer value
specifying the patient identification number; Y1:
an integer value, the number of seizures during the first
two week period; Y2: an integer value, the number of
seizures during the second two week period; Y3: an integer
value, the number of seizures during the third two week period.
Y4: an integer value, the number of seizures during the
fourth two week period; Base: an integer value giving
the eight-week baseline seizure count; Age: an integer
value giving the age of the parient in years; Trt:
the treatment: a factor with levels placebo and progabide;
Ysum: an integer value, the sum of Y1, Y2, Y3 and Y4;
sumY: an integer value, the sum of Y1, Y2, Y3 and Y4;
Age10: a numeric value, Age divided by 10; Base4:
a numeric value, Base divided by 4.
Format: Numeric, 59 rows and 12 columns.
Breslow, N. E., and Clayton, D. G. (1993), "Approximate Inference in Generalized Linear Mixed Models," Journal of the American Statistical Association, Vol. 88, No. 421, pp. 9-25.
Thrall, P. F., and Vail, S. C. (1990), "Some Covariance Models for Longitudinal Count Data With Overdispersion," Biometrics, Vol. 46, pp. 657-671.
data(breslow.dat)data(breslow.dat)
This data set corresponds to a study in automatic vehicle recognition. Each of the 218 rows corresponds to a view of a bus silhouette, and contains 18 attributes of the image. It was decided to exclude variable 9 and divide the remaining variables by their MADN’s.
data(bus)data(bus)
An object of class "data.frame".
Description: The following features were extracted from the silhouettes. 1. compactness 2. circularity 3. distance circularity 4. radius ratio 5. principal axis aspect ratio 6. maximum length aspect ratio 7. scatter ratio 8. elongatedness 9. principal axis rectangularity 10. maximum length rectangularity 11. scaled variance along major axis 12. scaled variance along minor axis 13. scaled radius of gyration 14. skewness about major axis 15. skewness about minor axis 16. kurtosis about minor axis 17. kurtosis about major axis 18. hollows ratio
Format: Numeric, 218 rows and 18 columns.
Hettich, S. and Bay, S.D. (1999), The UCI KDD Archive http://kdd.ics.uci.edu. Irvine, CA: University of California, Department of Information and Computer Science.
data(bus)data(bus)
The estimated covariance matrix of the DCML regression estimator. This function is used internally and not meant to be used directly.
cov.dcml(res.LS, res.R, CC, sig.R, t0, p, n, control)cov.dcml(res.LS, res.R, CC, sig.R, t0, p, n, control)
res.LS |
vector of residuals from the least squares fit |
res.R |
vector of residuals from the robust regression fit |
CC |
estimated covariance matrix of the robust regression estimator |
sig.R |
robust estimate of the scale of the residuals |
t0 |
mixing parameter |
p, n
|
the dimensions of the problem, needed for the finite sample correction of the tuning constant of the M-scale |
control |
a list of control parameters as returned by |
The covariance matrix estimate.
Victor Yohai, [email protected]
Compute an estimate of the covariance/correlation matrix and location vector using classical methods.
covClassic( data, corr = FALSE, center = TRUE, distance = TRUE, na.action = na.fail, unbiased = TRUE )covClassic( data, corr = FALSE, center = TRUE, distance = TRUE, na.action = na.fail, unbiased = TRUE )
data |
a numeric matrix or data frame containing the data. |
corr |
a logical flag. If |
center |
a logical flag or a numeric vector of length |
distance |
a logical flag. If |
na.action |
a function to filter missing data. The default |
unbiased |
a logical flag. If |
Its main intention is to return an object compatible to that
produced by covRob, but fit using classical methods.
a list with class “covClassic” containing the following elements:
center |
a numeric vector containing the estimate of the location vector. |
cov |
a numeric matrix containing the estimate of the covariance matrix. |
cor |
a numeric matrix containing the estimate of the correlation matrix if the argument |
dist |
a numeric vector containing the squared Mahalanobis distances. Only present if |
call |
an image of the call that produced the object with all the arguments named. The matched call. |
Originally, and in S-PLUS, this function was called cov; it has
been renamed, as that did mask the function in the standard package stats.
data(wine) round( covClassic(wine)$cov, 2)data(wine) round( covClassic(wine)$cov, 2)
This function computes robust estimators for multivariate location and scatter.
covRob(X, type = "auto", maxit = 50, tol = 1e-04, corr = FALSE)covRob(X, type = "auto", maxit = 50, tol = 1e-04, corr = FALSE)
X |
a data matrix with observations in rows. |
type |
a string indicating which estimator to compute. Valid options are "Rocke" for Rocke's S-estimator, "MM" for an MM-estimator with a SHR rho function, or "auto" (default) which selects "Rocke" if the number of variables is greater than or equal to 10, and "MM" otherwise. |
maxit |
Maximum number of iterations, defaults to 50. |
tol |
Tolerance for convergence, defaults to 1e-4. |
corr |
A logical value. If |
This function computes robust estimators for multivariate location and scatter.
The default behaviour (type = "auto") computes a "Rocke" estimator
(as implemented in covRobRocke) if the number
of variables is greater than or equal to 10, and an MM-estimator with a
SHR rho function (as implemented in covRobMM) otherwise.
A list with class “covClassic” with the following components:
center |
The location estimate. |
cov |
The scatter matrix estimate, scaled for consistency at the normal distribution. |
cor |
The correlation matrix estimate, if the argument |
dist |
Robust Mahalanobis distances |
wts |
weights |
call |
an image of the call that produced the object with all the arguments named. The matched call. |
mu |
The location estimate. Same as |
V |
The scatter matrix estimate, scaled for consistency at the normal distribution. Same as |
Ricardo Maronna, [email protected]
http://www.wiley.com/go/maronna/robust
data(bus) X0 <- as.matrix(bus) X1 <- X0[,-9] tmp <- covRob(X1) round(tmp$cov[1:10, 1:10], 3) tmp$mudata(bus) X0 <- as.matrix(bus) X1 <- X0[,-9] tmp <- covRob(X1) round(tmp$cov[1:10, 1:10], 3) tmp$mu
This function computes an MM robust estimator for multivariate location and scatter with the "SHR" loss function.
covRobMM(X, maxit = 50, tolpar = 1e-04, corr = FALSE)covRobMM(X, maxit = 50, tolpar = 1e-04, corr = FALSE)
X |
a data matrix with observations in rows. |
maxit |
Maximum number of iterations. |
tolpar |
Tolerance to decide converngence. |
corr |
A logical value. If |
This function computes an MM robust estimator for multivariate location and scatter with the "SHR" loss function.
A list with class “covRob” containing the following elements
center |
The location estimate. |
cov |
The scatter matrix estimate, scaled for consistency at the normal distribution. Same as |
cor |
The correlation matrix estimate, if the argument |
dist |
Robust Mahalanobis distances |
wts |
weights |
call |
an image of the call that produced the object with all the arguments named. The matched call. |
mu |
The location estimate. Same as |
V |
The scatter or correlation matrix estimate, scaled for consistency at the normal distribution |
Ricardo Maronna, [email protected]
http://www.wiley.com/go/maronna/robust
data(bus) X0 <- as.matrix(bus) X1 <- X0[,-9] tmp <- covRobMM(X1) round(tmp$cov[1:10, 1:10], 3) tmp$mudata(bus) X0 <- as.matrix(bus) X1 <- X0[,-9] tmp <- covRobMM(X1) round(tmp$cov[1:10, 1:10], 3) tmp$mu
This function computes Rocke's robust estimator for multivariate location and scatter.
covRobRocke( X, initial = "K", maxsteps = 5, propmin = 2, qs = 2, maxit = 50, tol = 1e-04, corr = FALSE )covRobRocke( X, initial = "K", maxsteps = 5, propmin = 2, qs = 2, maxit = 50, tol = 1e-04, corr = FALSE )
X |
a data matrix with observations in rows. |
initial |
A character indicating the initial estimator. Valid options are 'K' (default) for the Pena-Prieto 'KSD' estimate, and 'mve' for the Minimum Volume Ellipsoid. |
maxsteps |
Maximum number of steps for the line search section of the algorithm. |
propmin |
Regulates the proportion of weights computed from the initial estimator that will be different from zero. The number of observations with initial non-zero weights will be at least p (the number of columns of X) times propmin. |
qs |
Tuning paramater for Rocke's loss functions. |
maxit |
Maximum number of iterations. |
tol |
Tolerance to decide converngence. |
corr |
A logical value. If |
This function computes Rocke's robust estimator for multivariate location and scatter.
A list with class “covRob” containing the following elements:
center |
The location estimate. |
cov |
The scatter matrix estimate, scaled for consistency at the normal distribution. |
cor |
The correlation matrix estimate, if the argument |
dist |
Robust Mahalanobis distances. |
wts |
weights |
call |
an image of the call that produced the object with all the arguments named. The matched call. |
mu |
The location estimate. Same as |
V |
The scatter (or correlation) matrix estimate, scaled for consistency at the normal distribution. Same as |
sig |
sig |
gamma |
Final value of the constant gamma that regulates the efficiency. |
Ricardo Maronna, [email protected]
http://www.wiley.com/go/maronna/robust
data(bus) X0 <- as.matrix(bus) X1 <- X0[,-9] tmp <- covRobRocke(X1) round(tmp$cov[1:10, 1:10], 3) tmp$mudata(bus) X0 <- as.matrix(bus) X1 <- X0[,-9] tmp <- covRobRocke(X1) round(tmp$cov[1:10, 1:10], 3) tmp$mu
This function computes the DCML regression estimator. This function is used
internally by lmrobdetDCML, and not meant to be used
directly.
DCML(x, y, z, z0, control)DCML(x, y, z, z0, control)
x |
design matrix |
y |
response vector |
z |
|
z0 |
least squares fit as returned by |
control |
a list of control parameters as returned by |
a list with the following components
coefficients |
the vector of regression coefficients |
cov |
the estimated covariance matrix of the DCML regression estimator |
residuals |
the vector of regression residuals from the DCML fit |
scale |
a robust residual (M-)scale estimate |
t0 |
the mixing proportion between the least squares and robust regression estimators |
Victor Yohai, [email protected], Matias Salibian-Barrera, [email protected]
http://www.wiley.com/go/maronna/robust
lmrobdetMM fitThis function computes the RFPE for the MM-estimators obtained with lmrobdetMM by
recomputing it, successively removing each of a number of specified terms.
It is used internally by step.lmrobdetMM and not meant to be used
directly.
## S3 method for class 'lmrobdetMM' drop1(object, scope, scale, keep, ...)## S3 method for class 'lmrobdetMM' drop1(object, scope, scale, keep, ...)
object |
the |
scope |
an optional |
scale |
an optional residual scale estimate. If missing the residual
scale estimate in |
keep |
a character vector of names of components that should be saved for each subset model.
Only names from the set |
... |
additional parameters to match generic method |
An anova object consisting of the term labels, the degrees of freedom, and Robust Final
Prediction Errors (RFPE) for each subset model. If keep is missing, the anova object is
returned. If keep is present, a list with components "anova" and "keep" is returned.
In this case, the "keep" component is a matrix of mode "list", with a column for each
subset model, and a row for each component kept.
Victor Yohai, [email protected], Matias Salibian-Barrera, [email protected]
http://www.wiley.com/go/maronna/robust
This function uses a fast algorithm to compute the Minimum Volume Ellipsoid (MVE) for multivariate location and scatter.
fastmve(x, nsamp = 500)fastmve(x, nsamp = 500)
x |
data matrix (n x p) with cases stored in rows. |
nsamp |
number of random starts for the iterative algorithm, these are constructed using subsamples of the data. |
This function computes the Minimum Volume
Ellipsoid (MVE) for multivariate location and scatter, using a
fast algorithm related to the fast algorithm for S-regression
estimators (see lmrob).
A list with the following components:
center |
a vector with the robust multivariate location estimate |
cov |
a matrix with the robust covariance / scatter matrix estimate |
scale |
A scalar that equals the median of the mahalanobis distances of the
data to the |
best |
Indices of the observations that correspond to the MVE estimator |
nsamp |
Number of random starts used for the iterative algorithm |
nsing |
Number of random subsamples (among the |
Matias Salibian-Barrera, [email protected]
http://www.wiley.com/go/maronna/robust
data(bus) X0 <- as.matrix(bus) X1 <- X0[,-9] tmp <- fastmve(X1) round(tmp$cov[1:10, 1:10], 3) tmp$centerdata(bus) X0 <- as.matrix(bus) X1 <- X0[,-9] tmp <- fastmve(X1) round(tmp$cov[1:10, 1:10], 3) tmp$center
Determinations of the copper content in wholemeal flour (in parts per million), sorted in ascending order. Format: numeric vector of size 24.
data(flour)data(flour)
An object of class "data.frame".
Analytical Methods Committee (1989), Robust statistics-How not to reject outliers, Analyst, 114, 1693-1702.
References go here.
data(flour)data(flour)
Measurements of the presence of seven chemical constituents in 76 pieces of glass from nonfloat car windows.
data(glass)data(glass)
An object of class "data.frame".
Format: 76 cases and 7 continuous variables. Description: The columns are: 1. RI refractive index 2. Na2O sodium oxide (unit measurement: weight percent in corresponding oxide, as are the rest of attributes) 3. MgO magnesium oxide 4. Al2O3 aluminum oxide 5. SiO2 silcon oxide 6. K2O potassium oxide 7. CaO calcium oxide
Hettich, S. and Bay, S.D. (1999), The UCI KDD Archive http://kdd.ics.uci.edu, Irvine, CA: University of California, Department of Information and Computer Science.
data(glass)data(glass)
Prevalence rates in percent for men aged 55–64 with hearing levels 16 decibels or more above the audiometric zero.
data(hearing)data(hearing)
An object of class "data.frame".
Format: Two-way ANOVA. Description: The rows correspond to different frequencies and to normal speech. 1. 500 hertz 2. 1000 hertz 3. 2000 hertz 4. 3000 hertz 5. 4000 hertz 6. 6000 hertz 7. Normal speech The columns classify the data in seven occupational groups: 1. professional–managerial 2. farm 3. clerical sales 4. craftsmen 5. operatives 6. service 7. laborers
Roberts, J. and Cohrssen, J. (1968), Hearing levels of adults, US National Center for Health Statistics Publications, Series 11, No. 31
data(hearing)data(hearing)
This function computes the tuning constant that yields an MM-regression estimator with a desired asymptotic efficiency when computed with a rho function in the corresponding family. The output of this function can be passed to the functions lmrobdet.control, scaleM and rho.
huber(e)huber(e)
e |
the desired efficiency of the corresponding regression estimator for Gaussian errors |
A length-1 vector with the corresponding tuning constant.
Kjell Konis
# Tuning parameters for an 85%-efficient M-estimator at a Gaussian model huber(.95)# Tuning parameters for an 85%-efficient M-estimator at a Gaussian model huber(.95)
These data are part of a synthetic aperture satellite radar image corresponding to a suburb of Munich, and contain the values corresponding to three frequency bands for each of 1573 pixels of a radar image.
data(image)data(image)
An object of class "data.frame".
Format: 1573 cases and 3 variables.
Source: Frery, A. (2005), Personal communication.
data(image)data(image)
This function computes robust multivariate location and scatter estimators using both random and deterministic starting points.
initPP(X, muldirand = 20, muldifix = 10, dirmin = 1000)initPP(X, muldirand = 20, muldifix = 10, dirmin = 1000)
X |
a data matrix with observations in rows. |
muldirand |
used to determine the number of random directions (candidates), which
is |
muldifix |
used to determine the number of random directions (candidates), which
is |
dirmin |
minimum number of random directions |
This function computes robust multivariate location and scatter using both Pen~a-Prieto and random candidates.
A list with the following components:
idx |
A zero/one vector with ones in the positions of the suspected outliers |
disma |
Robust squared Mahalanobis distances |
center |
Robust mean estimate |
cova |
Robust covariance matrix estimate |
t |
Outlyingness of data points |
Ricardo Maronna, [email protected], based on original code by D. Pen~a and J. Prieto
http://www.wiley.com/go/maronna/robust
data(bus) X0 <- as.matrix(bus) X1 <- X0[,-9] tmp <- initPP(X1) round(tmp$cov[1:10, 1:10], 3) tmp$centerdata(bus) X0 <- as.matrix(bus) X1 <- X0[,-9] tmp <- initPP(X1) round(tmp$cov[1:10, 1:10], 3) tmp$center
This function computes a robust version of the R^2 coefficient of determination.
It is used internally by lmrobdetMM,
and not meant to be used directly.
INVTR2(RR2, family, cc)INVTR2(RR2, family, cc)
RR2 |
the proportional difference in loss functions (a naive robust R^2 coefficient). |
family |
family string specifying the name of the family of loss function to be used (current valid options are "bisquare", "opt" and "mopt"). |
cc |
tuning parameters to be computed according to efficiency and / or breakdown considerations. See lmrobdet.control, bisquare, mopt and opt. |
This function computes a robust version of the R^2 coefficient.
It is used internally by lmrobdetMM,
and not meant to be used directly.
An unbiased version of the robust R^2 coefficient of determination.
Victor Yohai, [email protected]
http://www.wiley.com/go/maronna/robust
Records for 33 leukemia patients.
data(leuk.dat)data(leuk.dat)
An object of class "data.frame".
Description: The following features are present:
wbc: white blood cell count;
ag: presence or absence of a certain
morphological characteristic in the white cells; and
y: binary response
variable, equals 1 if the patient survives more than 52 weeks, 0 otherwise.
Format: Numeric, 33 rows and 3 columns.
Cook, R.D. and Weisberg, S. (1982). Residuals and Influence in Regression, Chapman and Hall; Johnson, W. (1985), Influence measures for logistic regression: another point of view, Biometrika, 72, 59-65.
data(leuk.dat)data(leuk.dat)
This function sets tuning parameters for the MM estimator implemented in lmrobdetMM and
the Distance Constrained Maximum Likelihood regression estimators
computed by lmrobdetDCML.
lmrobdet.control( bb = 0.5, efficiency = 0.95, family = "mopt", tuning.psi, tuning.chi, compute.rd = FALSE, corr.b = TRUE, split.type = "f", initial = "S", max.it = 100, refine.tol = 1e-07, rel.tol = 1e-07, refine.S.py = 1e-07, refine.PY = 10, solve.tol = 1e-07, trace.lev = 0, psc_keep = 0.5, resid_keep_method = "threshold", resid_keep_thresh = 2, resid_keep_prop = 0.2, py_maxit = 20, py_eps = 1e-05, mscale_maxit = 50, mscale_tol = 1e-06, mscale_rho_fun = "bisquare" )lmrobdet.control( bb = 0.5, efficiency = 0.95, family = "mopt", tuning.psi, tuning.chi, compute.rd = FALSE, corr.b = TRUE, split.type = "f", initial = "S", max.it = 100, refine.tol = 1e-07, rel.tol = 1e-07, refine.S.py = 1e-07, refine.PY = 10, solve.tol = 1e-07, trace.lev = 0, psc_keep = 0.5, resid_keep_method = "threshold", resid_keep_thresh = 2, resid_keep_prop = 0.2, py_maxit = 20, py_eps = 1e-05, mscale_maxit = 50, mscale_tol = 1e-06, mscale_rho_fun = "bisquare" )
bb |
tuning constant (between 0 and 1/2) for the M-scale used to compute the initial S-estimator. It
determines the robusness (breakdown point) of the resulting MM-estimator, which is
|
efficiency |
desired asymptotic efficiency of the final regression M-estimator. Defaults to 0.95. |
family |
string specifying the name of the family of loss function to be used (current valid options are "bisquare", "opt" and "mopt"). Incomplete entries will be matched to the current valid options. Defaults to "mopt". |
tuning.psi |
tuning parameters for the regression M-estimator computed with a rho function
as specified with argument |
tuning.chi |
tuning constant for the function used to compute the M-scale
used for the initial S-estimator. If missing, it is computed inside |
compute.rd |
logical value indicating whether robust leverage distances need to be computed. |
corr.b |
logical value indicating whether a finite-sample correction should be applied
to the M-scale parameter |
split.type |
determines how categorical and continuous variables are split. See
|
initial |
string specifying the initial value for the M-step of the MM-estimator. Valid
options are |
max.it |
maximum number of IRWLS iterations for the MM-estimator |
refine.tol |
relative convergence tolerance for the S-estimator |
rel.tol |
relative convergence tolerance for the IRWLS iterations for the MM-estimator |
refine.S.py |
relative convergence tolerance for the local improvements of the Pena-Yohai candidates for the S-estimator |
refine.PY |
number of refinement steps for the Pen~a-Yohai candidates |
solve.tol |
(for the S algorithm): relative tolerance for matrix inversion. Hence, this corresponds to |
trace.lev |
positive values (increasingly) provide details on the progress of the MM-algorithm |
psc_keep |
For |
resid_keep_method |
For |
resid_keep_thresh |
See parameter |
resid_keep_prop |
See parameter |
py_maxit |
Maximum number of iterations. See |
py_eps |
Relative tolerance for convergence. See |
mscale_maxit |
Maximum number of iterations for the M-scale algorithm. See |
mscale_tol |
Convergence tolerance for the M-scale algorithm. See |
mscale_rho_fun |
String indicating the loss function used for the M-scale. See |
The argument family specifies the name of the family of loss
function to be used. Current valid options are "bisquare", "opt", "mopt",
"optV0" and "moptV0". "mopt" is a modified version of the optimal psi
function to make it strictly increasing close to 0, and to make the
corresponding weight function non-increasing.
A list with the necessary tuning parameters.
As of RobStatTM Versopm 1.0.7, the opt and mopt rhos functions are calculated using polynomials, rather than using the standard normal error function (erf) as in versions of RobStatTM prior to 1.0.7. The numerical results one now gets with the opt or mopt choices will differ by small amounts from those in earlier RobStatTM versions. Users who wish to replicate results from releases prior to 1.0.7 may do so using the family arguments family = "optV0" or family = "moptV0". Note that the derivative of the rho loss function, known as the "psi" function, is not the derivative of the rho polynomial,instead it is still the analytic optimal psi function whose formula is given in the second of the Vignettes referenced just below.
For further details, see the Vignettes "Polynomial Opt and mOpt Rho Functions", and "Optimal Bias Robust Regression Psi and Rho".
Matias Salibian-Barrera, [email protected]
data(coleman, package='robustbase') m2 <- lmrobdetMM(Y ~ ., data=coleman, control=lmrobdet.control(refine.PY=50)) m2 summary(m2)data(coleman, package='robustbase') m2 <- lmrobdetMM(Y ~ ., data=coleman, control=lmrobdet.control(refine.PY=50)) m2 summary(m2)
This function computes robust Distance Constrained Maximum Likelihood estimators for linear models.
lmrobdetDCML( formula, data, subset, weights, na.action, model = TRUE, x = !control$compute.rd, y = FALSE, singular.ok = TRUE, contrasts = NULL, offset = NULL, control = lmrobdet.control() )lmrobdetDCML( formula, data, subset, weights, na.action, model = TRUE, x = !control$compute.rd, y = FALSE, singular.ok = TRUE, contrasts = NULL, offset = NULL, control = lmrobdet.control() )
formula |
a symbolic description of the model to be fit. |
data |
an optional data frame, list or environment containing
the variables in the model. If not found in |
subset |
an optional vector specifying a subset of observations to be used. |
weights |
an optional vector of weights to be used in the fitting process. |
na.action |
a function to indicates what should happen when the data contain NAs.
The default is set by the na.action setting of |
model |
logical value indicating whether to return the model frame |
x |
logical value indicating whether to return the model matrix |
y |
logical value indicating whether to return the vector of responses |
singular.ok |
logical value. If |
contrasts |
an optional list. See the |
offset |
this can be used to specify an a priori known component to be included in the linear predictor during fitting. An offset term can be included in the formula instead or as well, and if both are specified their sum is used. |
control |
a list specifying control parameters as returned by the function lmrobdet.control. |
This function computes Distance Constrained Maximum Likelihood regression estimators
computed using an MM-regression estimator based on Pen~a-Yohai
candidates (instead of subsampling ones).
This function makes use of the functions lmrob.fit,
lmrob..M..fit, .vcov.avar1, lmrob.S and
lmrob.lar, from robustbase,
along with utility functions used by these functions,
modified so as to include use of the analytic form of the
optimal psi and rho functions (for the optimal psi function , see
Section 5.8.1 of Maronna, Martin, Yohai and Salibian Barrera, 2019)
A list with the following components:
coefficients |
The estimated vector of regression coefficients |
scale |
The estimated scale of the residuals |
residuals |
The vector of residuals associated with the robust fit |
converged |
Logical value indicating whether IRWLS iterations for the MM-estimator have converged |
iter |
Number of IRWLS iterations for the MM-estimator |
rweightsMM |
Robustness weights for the MM-estimator |
fitted.values |
Fitted values associated with the robust fit |
rank |
Numeric rank of the fitted linear model |
cov |
The estimated covariance matrix of the regression estimates |
df.residual |
The residual degrees of freedom |
contrasts |
(only where relevant) the contrasts used |
xlevels |
(only where relevant) a record of the levels of the factors used in fitting |
call |
the matched call |
model |
if requested, the model frame used |
x |
if requested, the model matrix used |
y |
if requested, the response vector used |
na.action |
(where relevant) information returned by model.frame on the special handling of NAs |
Matias Salibian-Barrera, [email protected], based on lmrob
http://www.wiley.com/go/maronna/robust
data(coleman, package='robustbase') m1 <- lmrobdetDCML(Y ~ ., data=coleman) m1 summary(m1)data(coleman, package='robustbase') m1 <- lmrobdetDCML(Y ~ ., data=coleman) m1 summary(m1)
This function computes a robust likelihood ratio test for linear hypotheses.
lmrobdetLinTest(object1, object2)lmrobdetLinTest(object1, object2)
object1 |
an |
object2 |
an |
A list with the following components: c("test","chisq.pvalue","f.pvalue","df")
test |
The value of the F-statistic |
f.pvalue |
p-value based on the F distribution |
chisq.pvalue |
p-value based on the chi-squared distribution |
df |
degrees of freedom |
Victor Yohai, [email protected]
http://www.wiley.com/go/maronna/robust
data(oats) cont <- lmrobdet.control(bb = 0.5, efficiency = 0.85, family = "bisquare") oats1M <- lmrobM(response1 ~ variety+block, control=cont, data=oats) oats1M_var <- lmrobM(response1 ~ block, control=cont, data=oats) ( anov1M_var <- rob.linear.test(oats1M, oats1M_var) )data(oats) cont <- lmrobdet.control(bb = 0.5, efficiency = 0.85, family = "bisquare") oats1M <- lmrobM(response1 ~ variety+block, control=cont, data=oats) oats1M_var <- lmrobM(response1 ~ block, control=cont, data=oats) ( anov1M_var <- rob.linear.test(oats1M, oats1M_var) )
This function computes an MM-regression estimators for linear models using deterministic starting points.
lmrobdetMM( formula, data, subset, weights, na.action, model = TRUE, x = !control$compute.rd, y = FALSE, singular.ok = TRUE, contrasts = NULL, offset = NULL, control = lmrobdet.control() )lmrobdetMM( formula, data, subset, weights, na.action, model = TRUE, x = !control$compute.rd, y = FALSE, singular.ok = TRUE, contrasts = NULL, offset = NULL, control = lmrobdet.control() )
formula |
a symbolic description of the model to be fit. |
data |
an optional data frame, list or environment containing
the variables in the model. If not found in |
subset |
an optional vector specifying a subset of observations to be used. |
weights |
an optional vector of weights to be used in the fitting process. |
na.action |
a function to indicates what should happen when the data contain NAs.
The default is set by the na.action setting of |
model |
logical value indicating whether to return the model frame |
x |
logical value indicating whether to return the model matrix |
y |
logical value indicating whether to return the vector of responses |
singular.ok |
logical value. If |
contrasts |
an optional list. See the |
offset |
this can be used to specify an a priori known component to be included in the linear predictor during fitting. An offset term can be included in the formula instead or as well, and if both are specified their sum is used. |
control |
a list specifying control parameters as returned by the function lmrobdet.control. |
This function computes MM-regression estimators
computed using Pen~a-Yohai candidates (instead of subsampling ones).
This function makes use of the functions lmrob.fit,
lmrob..M..fit, .vcov.avar1, lmrob.S and
lmrob.lar, from robustbase,
along with utility functions used by these functions,
modified so as to include use of the analytic form of the
optimal psi and rho functions (for the optimal psi function , see
Section 5.8.1 of Maronna, Martin, Yohai and Salibian Barrera, 2019).
A list with the following components:
coefficients |
The estimated vector of regression coefficients |
scale |
The robust residual M-scale estimate using the final residuals from the converged iterated weighted least square (IRWLS) algorithm final estimate |
residuals |
The vector of residuals associated with the robust fit |
loss |
Value of the objective function at the final MM-estimator |
converged |
Logical value indicating whether IRWLS iterations for the MM-estimator have converged |
iter |
Number of IRWLS iterations for the MM-estimator |
rweights |
Robustness weights for the MM-estimator |
fitted.values |
Fitted values associated with the robust fit |
rank |
Numeric rank of the fitted linear model |
cov |
The estimated covariance matrix of the regression estimates |
df.residual |
The residual degrees of freedom |
degree.freedom |
The residual degrees of freedom |
scale.S |
Minimum robust scale associated with the preliminary highly robust but inefficient S-estimator. |
r.squared |
The robust multiple correlation coefficient |
adj.r.squared |
The adjusted robust multiple correlation coefficient taking into account the degrees of freedom of each term |
contrasts |
(only where relevant) the contrasts used |
xlevels |
(only where relevant) a record of the levels of the factors used in fitting |
call |
the matched call |
model |
if requested, the model frame used |
x |
if requested, the model matrix used |
y |
if requested, the response vector used |
terms |
The terms object used. |
iters.py |
The number of refinement iterations for each Pena-Yohai candidate for the S-estimator. |
iters.const |
The number of refinement iterations used to compute the estimator without covariates (to calculate the robust R^2). |
assign |
Used to separate continuous from categorical columns in the design matrix |
na.action |
(where relevant) information returned by model.frame on the special handling of NAs |
This is done by the user choice of family = "opt" or family = "mopt" in the function lmrobdet.control. As of RobStatTM Versopm 1.0.7, the opt and mopt rhos functions are calculated using polynomials, rather than using the standard normal error function (erf) as in versions of RobStatTM prior to 1.0.7. The numerical results one now gets with the opt or mopt choices will differ by small amounts from those in earlier RobStatTM versions. Users who wish to replicate results from releases prior to 1.0.7 may do so using the family arguments family = "optV0" or family = "moptV0". Note that the derivative of the rho loss function, known as the "psi" function, is not the derivative of the rho polynomial, instead it is still the optimal psi function referred to above.
For further details, see the Vignettes "Polynomial Opt and mOpt Rho Functions", and "Optimal Bias Robust Regression Psi and Rho".
Matias Salibian-Barrera, [email protected], based on lmrob from package robustbase
http://www.wiley.com/go/maronna/robust
data(coleman, package='robustbase') m2 <- lmrobdetMM(Y ~ ., data=coleman) m2 summary(m2)data(coleman, package='robustbase') m2 <- lmrobdetMM(Y ~ ., data=coleman) m2 summary(m2)
This function computes the robust Final Prediction Errors (RFPE) for a robust regression fit using M-estimates.
lmrobdetMM.RFPE(object, scale = NULL, bothVals = FALSE)lmrobdetMM.RFPE(object, scale = NULL, bothVals = FALSE)
object |
an object of class |
scale |
a numeric value specifying the scale estimate used to compute the RFPE. Usually this
should be the scale estimate from an encompassing model. If |
bothVals |
a logical value: if |
If the argument bothVals is FALSE, the robust final prediction error (numeric). Otherwise,
the two terms of the RFPE expression in equation (5.39), Section 5.6.2 of Maronna
et al. (2019), http://www.wiley.com/go/maronna/robust, are returned separately
in a list with components named minRhoMM.C and penaltyRFPE
Victor Yohai, [email protected], Matias Salibian-Barrera, [email protected]
http://www.wiley.com/go/maronna/robust
data(coleman, package='robustbase') m2 <- lmrobdetMM(Y ~ ., data=coleman) lmrobdetMM.RFPE(m2)data(coleman, package='robustbase') m2 <- lmrobdetMM(Y ~ ., data=coleman) lmrobdetMM.RFPE(m2)
This function computes a robust regression estimator for a linear models with fixed designs.
lmrobM( formula, data, subset, weights, na.action, model = TRUE, x = FALSE, y = FALSE, singular.ok = TRUE, contrasts = NULL, offset = NULL, control = lmrobM.control() )lmrobM( formula, data, subset, weights, na.action, model = TRUE, x = FALSE, y = FALSE, singular.ok = TRUE, contrasts = NULL, offset = NULL, control = lmrobM.control() )
formula |
a symbolic description of the model to be fit. |
data |
an optional data frame, list or environment containing
the variables in the model. If not found in |
subset |
an optional vector specifying a subset of observations to be used. |
weights |
an optional vector of weights to be used in the fitting process. |
na.action |
a function to indicates what should happen when the data contain NAs.
The default is set by the na.action setting of |
model |
logical value indicating whether to return the model frame |
x |
logical value indicating whether to return the model matrix |
y |
logical value indicating whether to return the vector of responses |
singular.ok |
logical value. If |
contrasts |
an optional list. See the |
offset |
this can be used to specify an a priori known component to be included in the linear predictor during fitting. An offset term can be included in the formula instead or as well, and if both are specified their sum is used. |
control |
a list specifying control parameters as returned by the function lmrobM.control. |
This function computes robust regression estimators for linear
models with fixed designs. It computes an L1 estimator,
and uses it as a starting point to find a minimum of a
re-descending M estimator. The scale is set to a quantile of the
absolute residuals from the L1 estimator.
This function makes use of the functions lmrob.fit,
lmrob..M..fit, .vcov.avar1, lmrob.S and
lmrob.lar, from robustbase,
along with utility functions used by these functions,
modified so as to include use of the analytic form of the
optimal psi and rho functions (for the optimal psi function , see
Section 5.8.1 of Maronna, Martin, Yohai and Salibian Barrera, 2019)
A list with the following components:
coefficients |
The estimated vector of regression coefficients |
scale |
The estimated scale of the residuals |
residuals |
The vector of residuals associated with the robust fit |
converged |
Logical value indicating whether IRWLS iterations for the MM-estimator have converged |
iter |
Number of IRWLS iterations for the MM-estimator |
rweights |
Robustness weights for the MM-estimator |
fitted.values |
Fitted values associated with the robust fit |
rank |
Numeric rank of the fitted linear model |
cov |
The estimated covariance matrix of the regression estimates |
df.residual |
The residual degrees of freedom |
contrasts |
(only where relevant) the contrasts used |
xlevels |
(only where relevant) a record of the levels of the factors used in fitting |
call |
the matched call |
model |
if requested, the model frame used |
x |
if requested, the model matrix used |
y |
if requested, the response vector used |
na.action |
(where relevant) information returned by model.frame on the special handling of NAs |
Victor Yohai, [email protected], based on lmrob
http://www.wiley.com/go/maronna/robust
data(shock) cont <- lmrobM.control(bb = 0.5, efficiency = 0.85, family = "bisquare") shockrob <- lmrobM(time ~ n.shocks, data = shock, control=cont) shockrob summary(shockrob)data(shock) cont <- lmrobM.control(bb = 0.5, efficiency = 0.85, family = "bisquare") shockrob <- lmrobM(time ~ n.shocks, data = shock, control=cont) shockrob summary(shockrob)
This function sets tuning parameters for the M estimators of regression implemented
in lmrobM.
lmrobM.control( bb = 0.5, efficiency = 0.99, family = "opt", tuning.chi, tuning.psi, max.it = 100, rel.tol = 1e-07, mscale_tol = 1e-06, mscale_maxit = 50, trace.lev = 0 )lmrobM.control( bb = 0.5, efficiency = 0.99, family = "opt", tuning.chi, tuning.psi, max.it = 100, rel.tol = 1e-07, mscale_tol = 1e-06, mscale_maxit = 50, trace.lev = 0 )
bb |
tuning constant (between 0 and 1/2) for the M-scale used to compute the residual scale estimator. Defaults to 0.5. |
efficiency |
desired asymptotic efficiency of the final regression M-estimator. Defaults to 0.85. |
family |
string specifying the name of the family of loss function to be used (current valid options are "bisquare", "opt" and "mopt"). Incomplete entries will be matched to the current valid options. |
tuning.chi |
tuning constant for the function used to compute the M-scale
used for the residual scale estimator. If missing, it is computed inside |
tuning.psi |
tuning parameters for the regression M-estimator computed with a rho function
as specified with argument |
max.it |
maximum number of IRWLS iterations for the M-estimator |
rel.tol |
relative covergence tolerance for the IRWLS iterations for the M-estimator |
mscale_tol |
Convergence tolerance for the M-scale algorithm. See |
mscale_maxit |
Maximum number of iterations for the M-scale algorithm. See |
trace.lev |
positive values (increasingly) provide details on the progress of the M-algorithm |
A list with the necessary tuning parameters.
Matias Salibian-Barrera, [email protected]
data(coleman, package='robustbase') m2 <- lmrobM(Y ~ ., data=coleman, control=lmrobM.control()) m2 summary(m2)data(coleman, package='robustbase') m2 <- lmrobM(Y ~ ., data=coleman, control=lmrobM.control()) m2 summary(m2)
This function computes M-estimators for location and scale.
locScaleM(x, psi = "mopt", eff = 0.95, maxit = 50, tol = 1e-04, na.rm = FALSE)locScaleM(x, psi = "mopt", eff = 0.95, maxit = 50, tol = 1e-04, na.rm = FALSE)
x |
a vector of univariate observations |
psi |
a string indicating which score function to use. Valid options are "bisquare", "huber", "opt" and "mopt". |
eff |
desired asymptotic efficiency. Valid options are 0.85, 0.9 and 0.95 (default) when
|
maxit |
maximum number of iterations allowed. |
tol |
tolerance to decide convergence of the iterative algorithm. |
na.rm |
a logical value indicating whether |
This function computes M-estimators for location and scale.
A list with the following components:
mu |
The location estimate |
std.mu |
Estimated standard deviation of the location estimator |
disper |
M-scale/dispersion estimate |
Ricardo Maronna, [email protected]
http://www.wiley.com/go/maronna/robust
set.seed(123) r <- rnorm(150, sd=1.5) locScaleM(r) # 10% of outliers, sd of good points is 1.5 set.seed(123) r2 <- c(rnorm(135, sd=1.5), rnorm(15, mean=-10, sd=.5)) locScaleM(r2)set.seed(123) r <- rnorm(150, sd=1.5) locScaleM(r) # 10% of outliers, sd of good points is 1.5 set.seed(123) r2 <- c(rnorm(135, sd=1.5), rnorm(15, mean=-10, sd=.5)) locScaleM(r2)
This function computes the M-estimator proposed by Bianco and Yohai for logistic regression. By default, an intercept term is included and p parameters are estimated. Modified by Yohai (2018) to take as initial estimator a weighted ML estimator with weights derived from the MCD estimator. For more details we refer to Croux, C., and Haesbroeck, G. (2002), "Implementing the Bianco and Yohai estimator for Logistic Regression"
logregBY(x0, y, intercept = 1, const = 0.5, kmax = 1000, maxhalf = 10)logregBY(x0, y, intercept = 1, const = 0.5, kmax = 1000, maxhalf = 10)
x0 |
matrix of explanatory variables; |
y |
vector of binomial responses (0 or 1); |
intercept |
1 or 0 indicating if an intercept is included or or not |
const |
tuning constant used in the computation of the estimator (default=0.5); |
kmax |
maximum number of iterations before convergence (default=1000); |
maxhalf |
max number of step-halving (default=10). |
A list with the following components:
coefficients |
estimates for the regression coefficients |
standard.deviation |
standard deviations of the coefficients |
fitted.values |
fitted values |
residual.deviances |
residual deviances |
components |
logical value indicating whether convergence was achieved |
objective |
value of the objective function at the minimum |
Christophe Croux, Gentiane Haesbroeck, Victor Yohai
http://www.wiley.com/go/maronna/robust
data(skin) Xskin <- as.matrix( skin[, 1:2] ) yskin <- skin$vasoconst skinBY <- logregBY(Xskin, yskin, intercept=1) skinBY$coeff skinBY$standard.deviationdata(skin) Xskin <- as.matrix( skin[, 1:2] ) yskin <- skin$vasoconst skinBY <- logregBY(Xskin, yskin, intercept=1) skinBY$coeff skinBY$standard.deviation
This function computes the weighted M-estimator of Bianco and Yohai in logistic regression. By default, an intercept term is included and p parameters are estimated. Modified by Yohai (2018) to take as initial estimator a weighted ML estimator computed with weights derived from the MCD estimator of the continuous explanatory variables. The same weights are used to compute the final weighted M-estimator. For more details we refer to Croux, C., and Haesbroeck, G. (2002), "Implementing the Bianco and Yohai estimator for Logistic Regression"
logregWBY(x0, y, intercept = 1, const = 0.5, kmax = 1000, maxhalf = 10)logregWBY(x0, y, intercept = 1, const = 0.5, kmax = 1000, maxhalf = 10)
x0 |
matrix of explanatory variables; |
y |
vector of binomial responses (0 or 1); |
intercept |
1 or 0 indicating if an intercept is included or or not |
const |
tuning constant used in the computation of the estimator (default=0.5); |
kmax |
maximum number of iterations before convergence (default=1000); |
maxhalf |
max number of step-halving (default=10). |
A list with the following components:
coefficients |
estimates for the regression coefficients |
standard.deviation |
standard deviations of the coefficients |
fitted.values |
fitted values |
residual.deviances |
residual deviances |
components |
logical value indicating whether convergence was achieved |
objective |
value of the objective function at the minimum |
Christophe Croux, Gentiane Haesbroeck, Victor Yohai
http://www.wiley.com/go/maronna/robust
data(skin) Xskin <- as.matrix( skin[, 1:2] ) yskin <- skin$vasoconst skinWBY <- logregWBY(Xskin, yskin, intercept=1) skinWBY$coeff skinWBY$standard.deviationdata(skin) Xskin <- as.matrix( skin[, 1:2] ) yskin <- skin$vasoconst skinWBY <- logregWBY(Xskin, yskin, intercept=1) skinWBY$coeff skinWBY$standard.deviation
This function computes a weighted likelihood estimator for the logistic model, where the weights penalize high leverage observations. In this version the weights are zero or one.
logregWML(x0, y, intercept = 1)logregWML(x0, y, intercept = 1)
x0 |
p x n matrix of explanatory variables, p is the number of explanatory variables, n is the number of observations |
y |
response vector |
intercept |
1 or 0 indicating if an intercept is included or or not |
A list with the following components:
coefficients |
vector of regression coefficients |
standard.deviation |
standard deviations of the regression coefficient estimators |
fitted.values |
vector with the probabilities of success |
residual.deviances |
residual deviances |
cov |
covariance matrix of the regression estimates |
objective |
value of the objective function at the minimum |
xweights |
vector of zeros and ones used to compute the weighted maimum likelihood estimator |
Victor Yohai
http://www.wiley.com/go/maronna/robust
data(skin) Xskin <- as.matrix( skin[, 1:2] ) yskin <- skin$vasoconst skinWML <- logregWML(Xskin, yskin, intercept=1) skinWML$coeff skinWML$standard.deviationdata(skin) Xskin <- as.matrix( skin[, 1:2] ) yskin <- skin$vasoconst skinWML <- logregWML(Xskin, yskin, intercept=1) skinWML$coeff skinWML$standard.deviation
Contents (in parts per million) of 22 chemical elements in 53 samples of rocks in Western Australia. Two columns (8 and 9) were selected for use in this book.
data(mineral)data(mineral)
An object of class "data.frame".
Format: Numeric with 53 rows and 2 columns:
Smith, R.E., Campbell, N.A. and Lichfield, A. (1984), Multivariate statistical techniques applied to pisolitic laterite geochemistry at Golden Grove, Western Australia, Journal of Geochemical Exploration, 22, 193-216.
data(mineral)data(mineral)
This function computes MM-regression estimator using Pen~a-Yohai
candidates for the initial S-estimator. This function is used
internally by lmrobdetMM, and not meant to be used
directly.
MMPY(X, y, control, mf)MMPY(X, y, control, mf)
X |
design matrix |
y |
response vector |
control |
a list of control parameters as returned by |
mf |
model frame |
an lmrob object witht the M-estimator
obtained starting from the S-estimator computed with the
Pen~a-Yohai initial candidates. The properties of the final
estimator (efficiency, etc.) are determined by the tuning constants in
the argument control.
Victor Yohai, [email protected], Matias Salibian-Barrera, [email protected]
http://www.wiley.com/go/maronna/robust
This function computes the tuning constant that yields an MM-regression estimator with a desired asymptotic efficiency when computed with a rho function in the corresponding family. The output of this function can be passed to the functions lmrobdet.control, scaleM and rho.
mopt(e)mopt(e)
e |
the desired efficiency of the corresponding regression estimator for Gaussian errors |
A vector with named elements containing the corresponding tuning parameters.
Kjell Konis
# Tuning parameters for an 85%-efficient M-estimator at a Gaussian model mopt(.85)# Tuning parameters for an 85%-efficient M-estimator at a Gaussian model mopt(.85)
This function computes the tuning constant that yields an MM-regression estimator with a desired asymptotic efficiency when computed with a rho function in the corresponding family. The output of this function can be passed to the functions lmrobdet.control, scaleM and rho.
moptv0(e)moptv0(e)
e |
the desired efficiency of the corresponding regression estimator for Gaussian errors |
A vector with named elements containing the corresponding tuning parameters.
Kjell Konis
# Tuning parameters for an 85%-efficient M-estimator at a Gaussian model moptv0(.85)# Tuning parameters for an 85%-efficient M-estimator at a Gaussian model moptv0(.85)
Neuralgia data. More details here.
data(neuralgia)data(neuralgia)
An object of class "data.frame".
Source goes here.
References go here.
data(neuralgia)data(neuralgia)
Yield of grain for eight varieties of oats in five replications of a randomized-block experiment
data(oats)data(oats)
An object of class "data.frame".
Format: Two-way ANOVA table with 8 rows and 5 columns.
Scheffe, H. (1959), Analysis of Variance. New York: John Wiley.
References go here.
data(oats)data(oats)
This function computes the tuning constant that yields an MM-regression estimator with a desired asymptotic efficiency when computed with a rho function in the corresponding family. The output of this function can be passed to the functions lmrobdet.control, scaleM and rho.
opt(e)opt(e)
e |
the desired efficiency of the corresponding regression estimator for Gaussian errors |
A vector with named elements containing the corresponding tuning parameters.
Kjell Konis
# Tuning parameters for an 85%-efficient M-estimator at a Gaussian model opt(.85)# Tuning parameters for an 85%-efficient M-estimator at a Gaussian model opt(.85)
This function computes the tuning constant that yields an MM-regression estimator with a desired asymptotic efficiency when computed with a rho function in the corresponding family. The output of this function can be passed to the functions lmrobdet.control, scaleM and rho.
optv0(e)optv0(e)
e |
the desired efficiency of the corresponding regression estimator for Gaussian errors |
A vector with named elements containing the corresponding tuning parameters.
Kjell Konis
# Tuning parameters for an 85%-efficient M-estimator at a Gaussian model optv0(.85)# Tuning parameters for an 85%-efficient M-estimator at a Gaussian model optv0(.85)
This function computes robust principal components based on the minimization of the "residual" M-scale.
pcaRobS(X, ncomp, desprop = 0.9, deltasca = 0.5, maxit = 100)pcaRobS(X, ncomp, desprop = 0.9, deltasca = 0.5, maxit = 100)
X |
a data matrix with observations in rows. |
ncomp |
desired (maximum) number of components |
desprop |
desired (minimum) proportion of explained variability (default = 0.9) |
deltasca |
"delta" parameter of the scale M-estimator (default=0.5) |
maxit |
maximum number of iterations (default= 100) |
A list with the following components:
q |
The actual number of principal components |
propex |
The actual proportion of unexplained variability |
eigvec |
Eigenvectors, in a |
fit |
an |
repre |
An |
propSPC |
A vector of length |
Ricardo Maronna, [email protected], based on original code by D. Pen~a and J. Prieto
http://www.wiley.com/go/maronna/robust
data(bus) X0 <- as.matrix(bus) X1 <- X0[,-9] ss <- apply(X1, 2, mad) mu <- apply(X1, 2, median) X <- scale(X1, center=mu, scale=ss) q <- 3 #compute three components rr <- pcaRobS(X, q, 0.99) round(rr$eigvec, 3)data(bus) X0 <- as.matrix(bus) X1 <- X0[,-9] ss <- apply(X1, 2, mad) mu <- apply(X1, 2, median) X <- scale(X1, center=mu, scale=ss) q <- 3 #compute three components rr <- pcaRobS(X, q, 0.99) round(rr$eigvec, 3)
This function uses the pcaRobS function to compute all principal components while behaving similarly to the prcomp function
prcompRob(x, rank. = NULL, delta.scale = 0.5, max.iter = 100L)prcompRob(x, rank. = NULL, delta.scale = 0.5, max.iter = 100L)
x |
data matrix with observations in rows |
rank. |
Maximal number of principal components to be used (optional) |
delta.scale |
"delta" parametor of the scale M-estimator (default = 0.5) |
max.iter |
maximum number of iterations (default = 100) |
sdev |
the standard deviation of the principal components |
rotation |
matrix containing the factor loadings |
x |
matrix containing the rotated data |
center |
the centering used |
Gregory Brownson, [email protected]
data(wine) p.wine <- prcompRob(wine) summary(p.wine) ## Choose only 5 p5.wine <- prcompRob(wine, rank. = 5) summary(p5.wine)data(wine) p.wine <- prcompRob(wine) summary(p.wine) ## Choose only 5 p5.wine <- prcompRob(wine, rank. = 5) summary(p5.wine)
This function performs iterative improvements for S- or M-estimators.
refine.sm( x, y, initial.beta, initial.scale, k = 50, conv = 1, b, cc, family, step = "M", tol )refine.sm( x, y, initial.beta, initial.scale, k = 50, conv = 1, b, cc, family, step = "M", tol )
x |
design matrix |
y |
vector of responses |
initial.beta |
vector of initial regression estimates |
initial.scale |
initial residual scale estimate. If missing the (scaled) median of the absolute residuals is used. |
k |
maximum number of refining steps to be performed |
conv |
an integer indicating whether to check for convergence (1) at each step, or to force running k steps (0) |
b |
tuning constant for the M-scale estimator, used if iterations are for an S-estimator. |
cc |
tuning constant for the rho function. |
family |
string specifying the name of the family of loss function to be used (current valid options are "bisquare", "opt" and "mopt") |
step |
a string indicating whether the iterations are to compute an S-estimator ('S') or an M-estimator ('M') |
tol |
tolerance to detect convergence (relative difference of consecutive vectors of parameters) |
This function performs iterative improvements for S- or M-estimators. Both iterations are formally the same, the only difference is that for M-iterations the residual scale estimate remains fixed, while for S-iterations it is updated at each step. In this case, we follow the Fast-S algorithm of Salibian-Barrera and Yohai an use one step updates for the M-scale, as opposed to a full computation. This as internal function.
A list with the following components:
beta.rw |
The updated vector of regression coefficients |
scale.rw |
The corresponding estimated residual scale |
converged |
A logical value indicating whether the algorithm converged |
Matias Salibian-Barrera, [email protected].
A monthly series of inward movement of residential telephone extensions in a fixed geographic area from January 1966 to May 1973.
data(resex)data(resex)
An object of class "data.frame".
Format: numeric vector of size 89.
Source Engineering, 2nd. Edition, New York, John Wiley.
Brubacher. S.R. (1974), Time series outlier detection and modeling with interpolation, Bell Laboratories Technical Memo.
data(resex)data(resex)
This function returns the value of the "rho" loss function used to compute either an M-scale estimator or a robust regression estimator. It currently can be used to compute the bisquare, optimal and modified optimal loss functions.
rho(u, family = " bisquare", cc, standardize = TRUE)rho(u, family = " bisquare", cc, standardize = TRUE)
u |
point or vector at which rho is to be evaluated |
family |
family string specifying the name of the family of loss function to be used (current valid options are "bisquare", "opt" and "mopt"). |
cc |
tuning parameters to be computed according to efficiency and / or breakdown considerations. See lmrobdet.control, bisquare, mopt and opt. |
standardize |
logical value determining whether the rho function is to be
standardized so that its maximum value is 1. See |
The value(s) of rho at u
Matias Salibian-Barrera, [email protected]
# Evaluate rho tuned for 85% efficiency rho(u=1.1, family='bisquare', cc=bisquare(.85)) # Evaluate rho tuned for 50% breakdown rho(u=1.1, family='opt', cc=lmrobdet.control(bb=.5, family='opt')$tuning.chi)# Evaluate rho tuned for 85% efficiency rho(u=1.1, family='bisquare', cc=bisquare(.85)) # Evaluate rho tuned for 50% breakdown rho(u=1.1, family='opt', cc=lmrobdet.control(bb=.5, family='opt')$tuning.chi)
The first derivative of the rho function
rhoprime(u, family, cc, standardize = FALSE)rhoprime(u, family, cc, standardize = FALSE)
u |
point or vector at which rho is to be evaluated |
family |
family string specifying the name of the family of loss function to be used (current valid options are "bisquare", "opt" and "mopt"). |
cc |
tuning parameters to be computed according to efficiency and / or breakdown considerations. See lmrobdet.control, bisquare, mopt and opt. |
standardize |
logical value determining whether the rho function is to be
standardized so that its maximum value is 1. See |
The value of the first derivative rho evaluated at u
Matias Salibian-Barrera, [email protected]
# Evaluate the derivative of a rho function tuned for 85% efficiency rhoprime(u=1.1, family='bisquare', cc=bisquare(.85)) # Evaluate the derivative of a rho function tuned for 50% breakdown rhoprime(u=1.1, family='opt', cc=lmrobdet.control(bb=.5, family='opt')$tuning.chi)# Evaluate the derivative of a rho function tuned for 85% efficiency rhoprime(u=1.1, family='bisquare', cc=bisquare(.85)) # Evaluate the derivative of a rho function tuned for 50% breakdown rhoprime(u=1.1, family='opt', cc=lmrobdet.control(bb=.5, family='opt')$tuning.chi)
The second derivative of the rho function
rhoprime2(u, family, cc, standardize = FALSE)rhoprime2(u, family, cc, standardize = FALSE)
u |
point or vector at which rho is to be evaluated |
family |
family string specifying the name of the family of loss function to be used (current valid options are "bisquare", "opt" and "mopt"). |
cc |
tuning parameters to be computed according to efficiency and / or breakdown considerations. See lmrobdet.control, bisquare, mopt and opt. |
standardize |
logical value determining whether the rho function is to be
standardized so that its maximum value is 1. See |
The value of the second derivative of rho evaluated at u
Matias Salibian-Barrera, [email protected]
# Evaluate the 2nd derivative of a rho function tuned for 85% efficiency rhoprime2(u=1.1, family='bisquare', cc=bisquare(.85)) # Evaluate the 2nd derivative of a rho function tuned for 50% breakdown rhoprime2(u=1.1, family='opt', cc=lmrobdet.control(bb=.5, family='opt')$tuning.chi)# Evaluate the 2nd derivative of a rho function tuned for 85% efficiency rhoprime2(u=1.1, family='bisquare', cc=bisquare(.85)) # Evaluate the 2nd derivative of a rho function tuned for 50% breakdown rhoprime2(u=1.1, family='opt', cc=lmrobdet.control(bb=.5, family='opt')$tuning.chi)
This function computes an M-scale, which is a robust
scale (spread) estimator.
M-estimators of scale are a robust alternative to
the sample standard deviation. Given a vector of
residuals r, the M-scale estimator s
solves the non-linear equation mean(rho(r/s, cc))=delta,
where delta determines the breakdown point of the
estimator, and cc is a tuning parameter
calculated to obtain consistency under a Gaussian model.
The breakdown point of the estimator is min(delta, 1-delta),
so the optimal choice for delta is 0.5. To obtain a
consistent estimator the constant
cc is chosen such that E(rho(Z, cc)) = delta, where
Z is a standard normal random variable.
scaleM( u, delta = 0.5, family = "bisquare", max.it = 100, tol = 1e-06, tolerancezero = .Machine$double.eps, tuning.chi = lmrobdet.control(family = family, bb = delta)$tuning.chi )scaleM( u, delta = 0.5, family = "bisquare", max.it = 100, tol = 1e-06, tolerancezero = .Machine$double.eps, tuning.chi = lmrobdet.control(family = family, bb = delta)$tuning.chi )
u |
vector of residuals |
delta |
the right hand side of the M-scale equation |
family |
string specifying the name of the family of loss function to be used (current valid options are "bisquare", "opt" and "mopt"). |
max.it |
maximum number of iterations allowed |
tol |
relative tolerance for convergence |
tolerancezero |
smallest (in absolute value) non-zero value accepted as a scale. Defaults to |
tuning.chi |
the tuning object as returned
by |
The iterative algorithm starts from the scaled median of
the absolute values of the input vector, and then
cycles through the equation s^2 = s^2 * mean(rho(r/s, cc)) / delta.
The scale estimate value at the last iteration or at convergence.
Matias Salibian-Barrera, [email protected]
set.seed(123) r <- rnorm(150, sd=1.5) scaleM(r) sd(r) # 10% of outliers, sd of good points is 1.5 set.seed(123) r2 <- c(rnorm(135, sd=1.5), rnorm(15, mean=-5, sd=.5)) scaleM(r2, family='opt') sd(r2)set.seed(123) r <- rnorm(150, sd=1.5) scaleM(r) sd(r) # 10% of outliers, sd of good points is 1.5 set.seed(123) r2 <- c(rnorm(135, sd=1.5), rnorm(15, mean=-5, sd=.5)) scaleM(r2, family='opt') sd(r2)
Times recorded for a rat to go through a shuttlebox in successive attempts. If the time exceeded 5 seconds, the rat received an electric shock for the duration of the next attempt. The data are the number of shocks received and the average time for all attempts between shocks.
data(shock)data(shock)
An object of class "data.frame".
Format: Numeric matrix with 16 rows and 2 columns
Bond, N.W. (1979), Impairment of shuttlebox avoidance-learning following repeated alcohol withdrawal episodes in rats, Pharmacology, Biochemistry and Behavior, 11, 589-591.
References go here.
data(shock)data(shock)
These data correspond to a study of the relationship between air inspiration and blood circulation in the skin.
data(skin)data(skin)
An object of class "data.frame".
Description: The covariates are the logarithms of the volume of air inspired (log VOL) and of the inspiration rate (log RATE). The response (column 3) is the presence or absence of vasoconstriction of the skin of the digits after air inspiration. Format Numeric, 23 rows and 3 columns.
Finney, D.J. (1947), The estimation from individual records of the relationship between dose and quantal response, Biometrika, 34, 320-334.
data(skin)data(skin)
This function computes a robust regression estimator when there
are categorical / dummy explanatory variables. It uses Pen~a-Yohai
candidates for the S-estimator. This function is used
internally by lmrobdetMM, and not meant to be used
directly.
SMPY(mf, y, control, split)SMPY(mf, y, control, split)
mf |
model frame |
y |
response vector |
control |
a list of control parameters as returned by |
split |
a list as returned by |
an lmrob object witht the M-estimator
obtained starting from the MS-estimator computed with the
Pen~a-Yohai initial candidates. The properties of the final
estimator (efficiency, etc.) are determined by the tuning constants in
the argument control.
Victor Yohai, [email protected], Matias Salibian-Barrera, [email protected]
http://www.wiley.com/go/maronna/robust
Observations from 21 days operation of a plant for the oxidation of ammonia as a stage in the production of nitric acid.
data(stackloss)data(stackloss)
An object of class "data.frame".
Format: 21 cases and 4 continuous variables. Description: The columns are: 1. air flow 2. cooling water inlet temperature (C) 3. acid concentration ( 4. Stack loss, defined as the percentage of ingoing ammonia that escapes unabsorbed (response)
Brownlee, K.A. (1965), Statistical Theory and Methodology in Science and Engineering, 2nd Edition, New York: John Wiley & Sons, Inc.
data(stackloss)data(stackloss)
This function performs stepwise model selection on a robustly fitted
linear model using the RFPE
criterion and the robust regression estimators computed with
lmrobdetMM. Only backwards stepwise is currently implemented.
step.lmrobdetMM( object, scope, direction = c("both", "backward", "forward"), trace = TRUE, keep = NULL, steps = 1000, whole.path = FALSE )step.lmrobdetMM( object, scope, direction = c("both", "backward", "forward"), trace = TRUE, keep = NULL, steps = 1000, whole.path = FALSE )
object |
a robust fit as returned by |
scope |
either a formula or a list with elements |
direction |
the direction of stepwise search. Currenly only |
trace |
logical. If |
keep |
a filter function whose input is a fitted model object and the associated AIC statistic, and whose output is arbitrary. Typically keep will select a subset of the components of the object and return them. The default is not to keep anything. |
steps |
maximum number of steps to be performed. Defaults to 1000, which should mean as many as needed. |
whole.path |
if |
Presently only backward stepwise selection is supported. During each step the
Robust Final Prediction Error (as computed by the function lmrobdetMM.RFPE) is
calculated for the current model and for each sub-model achievable by deleting a
single term. If the argument whole.path is FALSE, the function steps
to the sub-model with the lowest
Robust Final Prediction Error or, if the current model has the lowest Robust Final
Prediction Error, terminates. If the argument whole.path is TRUE, the
function steps through all smaller submodels removing, at each step, the variable
that most reduces the Robust Final Prediction Error. The scale estimate from object
is used to compute the Robust Final Prediction Error throughout the procedure.
If whole.path == FALSE the function returns the robust fit as obtained by lmrobdetMM using the final model.
If whole.path == TRUE a list is returned containing the RFPE of each model on the sequence
of submodels. The names of the components of this list are the formulas that correspods to each model.
Victor Yohai, [email protected], Matias Salibian-Barrera, [email protected]
http://www.wiley.com/go/maronna/robust
cont <- lmrobdet.control(bb = 0.5, efficiency = 0.85, family = "bisquare") set.seed(300) X <- matrix(rnorm(50*6), 50, 6) beta <- c(1,1,1,0,0,0) y <- as.vector(X %*% beta) + 1 + rnorm(50) y[1:6] <- seq(30, 55, 5) for (i in 1:6) X[i,] <- c(X[i,1:3],i/2,i/2,i/2) Z <- cbind(y,X) Z <- as.data.frame(Z) obj <- lmrobdetMM(y ~ ., data=Z, control=cont) out <- step.lmrobdetMM(obj)cont <- lmrobdet.control(bb = 0.5, efficiency = 0.85, family = "bisquare") set.seed(300) X <- matrix(rnorm(50*6), 50, 6) beta <- c(1,1,1,0,0,0) y <- as.vector(X %*% beta) + 1 + rnorm(50) y[1:6] <- seq(30, 55, 5) for (i in 1:6) X[i,] <- c(X[i,1:3],i/2,i/2,i/2) Z <- cbind(y,X) Z <- as.data.frame(Z) obj <- lmrobdetMM(y ~ ., data=Z, control=cont) out <- step.lmrobdetMM(obj)
The original data set contains an ensemble of shape feature extractors to the 2D silhouettes of different vehicles. The purpose is to classify a given silhouette as one of four types of vehicle, using a set of 18 features extracted from the silhouette. Here we deal with the "van" type, which has 217 cases. Description; The following features were extracted from the silhouettes. 1. compactness 2. circularity 3. distance circularity 4. radius ratio 5. principal axis aspect ratio 6. maximum length aspect ratio 7. scatter ratio 8. elongatedness 9. principal axis rectangularity 10. maximum length rectangularity 11. scaled variance along major axis 12. scaled variance along minor axis 13. scaled radius of gyration 14. skewness about major axis 15. skewness about minor axis 16. kurtosis about minor axis 17. kurtosis about major axis 18. hollows ratio
data(vehicle)data(vehicle)
An object of class "data.frame".
Format: Numeric, 217 rows and 18 columns.
Turing Institute, Glasgow, and are available at https://archive.ics.uci.edu/ml/datasets/Statlog+(Vehicle+Silhouettes).
data(vehicle)data(vehicle)
Waste data. The original data are the result of a study on production waste and land use by Golueke and McGauhey (1970), and contain nine variables, of which we consider six.
data(waste)data(waste)
An object of class "data.frame".
Format: 40 cases and 6 continuous variables. Description: The columns are 1. industrial land (acres) 2. fabricated metals (acres) 3. trucking and wholesale trade (acres) 4. retail trade (acres) 5. restaurants and hotels (acres) 6. solid waste (millions of tons), response
Golueke, C.G. and McGauhey, P.H. (1970), Comprehensive Studies of Solid Waste Management, US Department of Health, Education and Welfare, Public Health Services Publication No. 2039.
Golueke, C.G. and McGauhey, P.H. (1970), Comprehensive Studies of Solid Waste Management, US Department of Health, Education and Welfare, Public Health Services Publication No. 2039.
data(waste)data(waste)
It contains, for each of 59 wines grown in the same region in Italy, the quantities of 13 constituents. The original purpose of the analysis was to classify wines from different cultivars by means of these measurements. In this example we treat cultivar one.
data(wine)data(wine)
An object of class "data.frame".
Format: Numeric, 59 rows and 13 columns. Description: The attributes are: 1. Alcohol 2. Malic acid 3. Ash 4. Alcalinity of ash 5. Magnesium 6. Total phenols 7. Flavanoids 8. Nonflavanoid phenols 9. Proanthocyanins 10. Color intensity 11. Hue 12. OD280/OD315 of diluted wines 13. Proline
Hettich, S. and Bay, S.D. (1999), The UCI KDD Archive http://kdd.ics.uci.edu. Irvine, CA: University of California, Department of Information and Computer Science.
data(wine)data(wine)