sm.options {sm}R Documentation

Set or return options of sm library

Description

Provides a means to control the behaviour of the sm library such as the colour of the plotted lines, the size of the grid in 2-D estimation, the set of evaluations points, and many others.

Usage

sm.options(...)

Arguments

... a list may be given as the only argument, or a vector of character strings given as the only argument, or any number of arguments may be in the name=value form , or no argument at all may be given. See the Value and Side Effects sections for explanation.
Arguments which are set by a function call will remain in effect until the end of the current S-plus session, unless overwritten by a subsequent call. In addition, they can be added as optional parameters of calls to specific functions of the sm library; in this case, their effect is limited to that function call. See the documentation of specific functions for the list of options which are recognised by that function. Notice that some options are relevant only to some functions.
    add
    a logical value which controls whether the density estimate is added to the current plot. Its default value is FALSE, which creates a new plot. This argument applies only with one-dimensional data or to contours created from two-dimensional data.
    band
    a logical value which controls whether the reference band appears on the plot. This argument applies only with one-dimensional data. Default: band=FALSE.
    col
    the colour used for plotting observed points and estimated curves. Where groups are used, col may be set to a vector of colours associated with the groups. Default: col=1.
    delta
    in sm.density, a value which will be added to the data before they are log transformed in the procedure to handle positive data. The value of delta is used only when positive takes the value TRUE. The default value is the smallest value observed in each dimension. This argument does not apply with three-dimensional data. Default: delta=NA
    describe
    logical flag whiich affects the behaviour of sm.script and provide.data. If describe=TRUE (default), a data documentation file is printed.
    df
    approximate degrees-of-freedom of the smoothing parameter used in sm.regression, when a numerical value of h is not specified. In this case, the equivalent value of h will be computed and included in the list returned on exit from sm.regression. Default value is 6 if x is a vector and 12 if x is a matrix.
    diff.ord
    in sm.regression, an integer defining the degree of differencing to be applied in the estimation process. When this argument is set to 1, the method of Rice, based on the squared differences of pairs of neighbouring observations, is used. When the argument is set to 2 (deafult), the method of Gasser, Sroka and Jennen-Steinmetz, based on differences between each observation and a linear interplotation from its two neighbours, is used.
    display
    This argument applies only with one- or two-dimensional data. The setting "none" will prevent any graphical output from being produced. In one dimensions, the default setting "line" will produce the estimate, while the setting "se" will in addition produce a variability band, showing the variability, but not the bias, of the estimate. In two dimensions, the default setting "persp" will produce a perspective plot of the estimate, while the settings "slice" and "image" will produce slice (contour) or image plots.
    eval.grid
    logical flag which controls how the options eval.points are used fow two-dimensional data. If eval.grid=TRUE (default), evaluation is perfomed at points obtained by the cross-product of the two columns of eval.points. If eval.grid=FALSE then evaluation is performed at points with coordinates specified by the coordinates in eval.points
    eval.points
    the points at which the density or the regression curve or surface estimate should be evaluated, for the values returned in the result of the function. This should be a vector for one-dimensional data and a two-column matrix for two-dimensional data. This argument does not apply with three-dimensional data.
    h.weights
    a vector of weights which multiply the smoothing parameter used in the kernel function at each observation. This argument does not apply with three-dimensional data. Default value: 1.
    hmult
    a factor which can be used to multiply the normal smoothing parameter before construction of the density estimate. Default value: 1.
    hull
    a logical value which controls whether the estimate is evaluated and plotted only on grid points which fall within the convex hull of the data. When this argument is set to FALSE, evaluation and plotting take place at all grid points where the contribution from at least one kernel function is non-negligible. Both of these settings ensure that the estimate is not evaluated at points where there are no observations nearby. This argument applies only to sm.regression for the case of two covariates.
    lty
    the line type used to plot the estimate. This argument applies only when the estimate is displayed as a curve or a countour. Default value: 1.
    method
    the method used to select smoothing parameters. In density estimation the default is "normal" which uses a vlue which is asymptotically optimal for the normal distribution. Other possibilities are "cv" for cross-validation and "sj" for the Sheather-Jones method. In nonparametric regression, the deault is "df" which selects a smoothing parameters associated with the approximate degrees of freedom given in the df option. Other possibilities are "cv" for cross-validation and "aicc" for an AIC-based method proposed by Hurvich, Simonoff and Tsai.
    nbins
    the number of bins used in one-dimensional binning operations; in two-dimensional cases, nbins refers to the number of bins formed along each axis. Bins with 0 observed frequencies are ignored. If nbins=0, binning is not performed; if nbins=NA (default), binning is switched on when the number of observations exceeds a certain threshold, which depends on the function.
    nboot
    number of samples generated in bootstraps. Default value: 100.
    ngrid
    the number of points in the regular grid used to plot the estimate. For two- and three-dimensional data, ngrid refers to the number of points along the axis in each dimension. The same parameter is also used by a few other functions which perform some form of search (e.g. hcv). Default value for sm.regression: 50 and 20 for 1-, 2-dimensional data, respectively. Default value for sm.density: 100, 50 and 20 for 1-, 2- and 3-dimensional data, respectively.
    panel
    a logical value which controls the appearance of a panel display, in the case of one- or two-dimensional data. The panel can be used to alter the value of the smoothing parameter. For one-dimensional data it can also launch an animation, and superimpose a normal reference band. This argument does not apply with three-dimensional data.
    pch
    the standard plotting charater identified for data plotting. Default value: 1.
    phi
    the vertical rotation (in degrees) of perspective plots of estimate in the form of surfaces. Default value: 40.
    poly.index
    an integer defining local constant (0) or local linear (1) smoothing. Default value: 1.
    positive
    a logical value which indicates whether the data should be assumed to take positive values only, in sm.density. When this argument is set to TRUE, a log transformation is applied to the data before construction of a density estimate. The result is transformed back to the original scale. This argument does not apply with three-dimensional data. Default value: FALSE.
    props
    a vector defining the proportions of the data to be included within each contour in a slice plot, from two-dimensional data, or a contour surface plot, from three-dimensional data. In the three-dimensional case only the first element of the vector will be used. This argument does not apply to one-dimensional data. Default value: c(75,50,25).
    rugplot
    logical flag which regulates whetehr a rugplot is superimposed to the density estimate, in the univariate case. Dafault value: TRUE.
    show.script
    logical flag which affects the behaviour of sm.script when this is called with non-empty argument. If show.script=TRUE (default) a window is opened to display the source code of the script.
    structure.2d
    the structure of the smoothing parameter in two-dimensional settings. The default is "scaled", which uses the structure (h*sd(x[,1]), h*sd(x[,2])). Other possibilities are "separate", which uses (h1, h2), and "common" which uses (h, h). The "common" option may be particularly appropriate when the data have a spatial origin, where distances in each variable havae the same meaning. Note that the "separate" option is not available when "method" is set to "df".
    test
    a logical flag controlling the production of a formal test, using the reference model as the null hypothesis. Default value: TRUE.
    theta
    the horizontal rotation (in degrees) of perspective plots of estimates in the form of surfaces. Default value: -30.
    verbose
    regulates the amount of messages and other output printed out. If verbose=0 only errors produce messages; if verbose=1 (default value) warnings and the more relevant numerical output are printed ; if verbose=2 more messages and more numerical output are printed.
    xlab
    the label attached to the x-axis.
    xlim
    the range of the horizontal axis of the plot. This argument does not apply with three-dimensional data.
    yht
    the upper limit of the vertical axis in a plot of a one-dimensional density estimate. The lower limit is always set to 0. This argument does not apply with two- or three-dimensional data.
    ylab
    the label attached to the y-axis.
    ylim
    the range of the vertical axis of the plot. This argument does not apply with three-dimensional data.
    zlab
    the label attached to the z-axis (three-dimensional plots only).
    zlim
    the range of the vertical axis when estimates are displayed as perspective plots.

Details

The parameter values set via a call to this function will remain in effect for the rest of the session, affecting the subsequent behaviour of the other functions of the sm library for which the given parameters are relevant.

This offers the possibility of customizing the functioning of the sm library, for instance by insertions of appropriate calls to sm.options in a load hook for package sm.

Value

a list with the updated values of the parameters. If the argument list is not empty, the returned list is invisible.

Examples

## Not run: 
sm.options(poly.index = 0)
# subsequent regression estimations will be performed using local means
# instead of local regression
#
sm.options(describe = FALSE)  
# turns off typing documentation files of data loaded by `sm.script'
# (works from command-line)
# 
## End(Not run)
[Package sm version 2.1-0 Index]