plot.stepmented: Plot method for stepmented objects
In segmented: Regression Models with Break-Points / Change-Points Estimation (with Possibly Random Effects)

plot.stepmented

R Documentation

Plot method for stepmented objects

Description

Takes a fitted stepmented object returned by stepmented() and plots (or adds) the fitted piecewise constant lines for the selected stepmented term.

Usage

## S3 method for class 'stepmented'
plot(x, term, add = FALSE, res = TRUE, conf.level=0, interc = TRUE, add.fx = FALSE, 
      psi.lines = TRUE, link=TRUE, const=NULL, res.col=grey(.15, alpha = .4), 
      surf=FALSE, zero.cor=TRUE, heurs=TRUE, shade=FALSE, se.type=c("cdf","abs","none"), 
      k=NULL, .vcov=NULL, leg="topleft", ...)

Arguments

`x`	a fitted `stepmented` object.
`term`	the stepmented variable having the piece-wise constant relationship to be plotted. If there is a single stepmented variable in the fitted model `x`, `term` can be omitted.
`add`	when `TRUE` the fitted lines are added to the current device.
`res`	when `TRUE` the fitted lines are plotted along with corresponding partial residuals.
`conf.level`	the confidence level for the pointwise confidence intervals for the expected values.
`interc`	if `TRUE` the computed components include the model intercept (if it exists).
`add.fx`	logical. If TRUE and the object fit also includes an additional term for the same stepmented variable, the plot also portrays such ‘additional’ term.
`psi.lines`	if `TRUE` vertical lines corresponding to the estimated changepoints are also drawn
`link`	if `FALSE` the fitted lines (and possibily the residuals) are reported on the response scale. Ignored if the fit object `x` is not a glm-like fit.
`const`	constant to add to each fitted segmented relationship (on the scale of the linear predictor) before plotting. If `const=NULL` and the fit includes a segmented interaction term (obtained via `seg(..,by)` in the formula), the group-specific intercept is included.
`res.col`	when `res=TRUE` it means the color of the points representing the partial residuals.
`surf`	if the object fit `x` includes 2 stepmented covariates (x1 and x2, say) with relevant estimated breakpoints, `surf=TRUE` will draw on the plane x1-x2 the areas splitted according to the estimated breakpoints with corresponding estimated means superimposed.
`zero.cor`	see `zero.cor` in `vcov.stepmented`; effective only if `conf.level>0`.
`heurs`	logical; if `TRUE`, heuristic (usually somewhat conservative) confidence intervals are computed and plotted; effective only if `conf.level>0`.
`shade`	if `TRUE` the pointwise confidence intervals are portrayed via shaded area; effective only if `conf.level>0`.
`se.type`	which standard errors should be computed? see `type` in `vcov.stepmented`; effective only if `conf.level>0`.
`k`	The value to be passed to `vcov.stepmented` to computed the standard errors.
`.vcov`	The estimate var-covariance matrix; if `NULL`, it is computed internally by `vcov.stepmented`.
`leg`	If the plot refers to stepmented relationships in groups, i.e. `term` has been specified as a vector, a legend is placed at the specified `leg` position. Put `NA` not to draw the legend.
`...`	other graphics parameters to pass to plotting commands: ‘col’, ‘lwd’ and ‘lty’ (that can be vectors and are recycled if necessary, see the example below) for the fitted piecewise constant lines; ‘ylab’, ‘xlab’, ‘main’, ‘sub’, ‘cex.axis’, ‘cex.lab’, ‘xlim’ and ‘ylim’ when a new plot is produced (i.e. when `add=FALSE`); ‘pch’ and ‘cex’ for the partial residuals (when `res=TRUE`, `res.col` is for the color).

Details

Produces (or adds to the current device) the fitted step-function like relationship between the response and the selected term. If the fitted model includes just a single ‘stepmented’ variable, term may be omitted. If surf=TRUE, and res=TRUE the point widths are proportional to the partial residual values.

Value

None.

Note

Implementation of confidence intervals for the conditional means in stepmented regression is under development; conf.level>0 should be used with care, especially with multiple jumpoints.

Author(s)

Vito M. R. Muggeo

Examples


#Following code in stepmented..
## Not run: 

par(mfrow=c(1,3))

plot(os,"x")
plot(os,"z")
plot(os,"z", add.fx=TRUE, psi.lines=FALSE ) 
lines(os, "z")

#display the 'surface'
par(mfrow=c(1,3))
plot(os, surf=TRUE, col=1, res.col=2)
plot(os, surf=TRUE, lty=2)
plot(x,z)
plot(os, surf=TRUE, add=TRUE, col=4, res=FALSE)


## End(Not run)

segmented documentation built on Oct. 25, 2024, 5:07 p.m.