### Name: plot.lm
### Title: Plot Diagnostics for an lm Object
### Aliases: plot.lm plot.mlm
### Keywords: hplot regression

### ** Examples

require(graphics)

## Analysis of the life-cycle savings data
## given in Belsley, Kuh and Welsch.
plot(lm.SR <- lm(sr ~ pop15 + pop75 + dpi + ddpi, data = LifeCycleSavings))

## 4 plots on 1 page;
## allow room for printing model formula in outer margin:
par(mfrow = c(2, 2), oma = c(0, 0, 2, 0))
plot(lm.SR)
plot(lm.SR, id.n = NULL)               # no id's
plot(lm.SR, id.n = 5, labels.id = NULL)# 5 id numbers

## Was default in R <= 2.1.x:
## Cook's distances instead of Residual-Leverage plot
plot(lm.SR, which = 1:4)

## Fit a smooth curve, where applicable:
plot(lm.SR, panel = panel.smooth)
## Gives a smoother curve
plot(lm.SR, panel = function(x,y) panel.smooth(x, y, span = 1))

par(mfrow=c(2,1))# same oma as above
plot(lm.SR, which = 1:2, sub.caption = "Saving Rates, n=50, p=5")

## Don't show: 
## An example with *long* formula that needs abbreviation:
for(i in 1:5) assign(paste("long.var.name",i,sep="."), runif(10))
plot(lm(long.var.name.1 ~
        long.var.name.2 + long.var.name.3 + long.var.name.4 + long.var.name.5))
## End Don't show