auto <- read.table("../data/auto.dat", header=TRUE)

#-----
library(gam)
#library(mgcv)

fit.gam<- gam(city.distance ~ s(engine.size) + s(curb.weight),  data=auto)
par(mfrow=c(1,2))
plot(fit.gam,se=T)

summary(fit.gam)
fit.gam.lm<- gam(city.distance ~ engine.size + s(engine.size) + curb.weight + s(curb.weight),  data=auto)

fit.glm<- glm(city.distance ~ engine.size + curb.weight,  data=auto)

fit.gam0 = gam(city.distance ~ s(engine.size) + curb.weight,  data=auto)


anova(fit.glm,fit.gam0,fit.gam,test="F")

anova(fit.gam0,fit.gam,test="F")

fit.gam2 =  gam(city.distance ~ s(engine.size,spar=0.1) + s(curb.weight,spar=0.1),  data=auto)
plot(fit.gam2,se=T)

fit.gam2 =  gam(city.distance ~ s(engine.size,spar=1) + s(curb.weight,spar=1),  data=auto)
plot(fit.gam2,se=T)