# plot.ppr: Plot Ridge Functions for Projection Pursuit Regression Fit

## Description

Plot the ridge functions for a projection pursuit regression (`ppr`) fit.

## Usage

 ```1 2 3 4 5 6``` ```## S3 method for class 'ppr' plot(x, ask, type = "o", cex = 1/2, main = quote(bquote( "term"[.(i)]*":" ~~ hat(beta[.(i)]) == .(bet.i))), xlab = quote(bquote(bold(alpha)[.(i)]^T * bold(x))), ylab = "", ...) ```

## Arguments

 `x` an R object of class `"ppr"` as produced by a call to `ppr`. `ask` the graphics parameter `ask`: see `par` for details. If set to `TRUE` will ask between the plot of each cross-section. `type` the type of line (see `plot.default`) to draw. `cex` plot symbol expansion factor (relative to `par("cex")`). `main, xlab, ylab` axis annotations, see also `title`. Can be an expression (depending on `i` and `bet.i`), as by default which will be `eval()`uated. `...` further graphical parameters, passed to `plot()`.

None

## Side Effects

A series of plots are drawn on the current graphical device, one for each term in the fit.

`ppr`, `par`
 ``` 1 2 3 4 5 6 7 8 9 10``` ```require(graphics) rock1 <- within(rock, { area1 <- area/10000; peri1 <- peri/10000 }) par(mfrow = c(3,2)) # maybe: , pty = "s" rock.ppr <- ppr(log(perm) ~ area1 + peri1 + shape, data = rock1, nterms = 2, max.terms = 5) plot(rock.ppr, main = "ppr(log(perm)~ ., nterms=2, max.terms=5)") plot(update(rock.ppr, bass = 5), main = "update(..., bass = 5)") plot(update(rock.ppr, sm.method = "gcv", gcvpen = 2), main = "update(..., sm.method=\"gcv\", gcvpen=2)") ```