Difference between revisions of "Bsplines.R"
From Organic Design wiki
(Seems to be a bug in variable naming from 'fit') |
(fixed bs bug) |
||
| Line 19: | Line 19: | ||
# p41 | # p41 | ||
| − | par(mfrow=c( | + | par(mfrow=c(3,1)) |
knots <- c(1:3,5,7,8,10) | knots <- c(1:3,5,7,8,10) | ||
| − | atx <- seq(0 | + | atx <- seq(0, 11, by=0.1) |
| − | for(ord in | + | for(ord in 2:4) { # ord cannot be 1 |
| − | B <- bs(x=atx, degree=ord, knots=knots, intercept=TRUE, Boundary.knots=c(0,11)) | + | B <- bs(x=atx, degree=ord-1, knots=knots, intercept=TRUE, Boundary.knots=c(0,11)) |
| + | # B <- predict(B, seq(0,11, length=101) # works | ||
matplot(atx, B[,1], type="l", ylim=0:1, lty=2) | matplot(atx, B[,1], type="l", ylim=0:1, lty=2) | ||
matlines(atx, B[,-1], col=1, lty=1) | matlines(atx, B[,-1], col=1, lty=1) | ||
Latest revision as of 03:10, 17 October 2007
Code snipits and programs written in R, S or S-PLUS library(splines)
- p38
pos <- function(x) ifelse(x>0, x, 0) x <- 1:7 y <- c(8,3,8,5,9,14,11) knot <- 4 plot(x,y)
- X <- cbind("int"=1,"x"=x,"x2"=x^2,"x3"=x^3, "xknot"=pos(x-knot)^3)
- fit <- lm(y~X-1)
fit <- lm(y~1+x+x^2+x^3+pos(x-knot)^3) xx <- seq(1,7, length=200) XX <- cbind("x"=xx) lines(xx, predict(fit, as.data.frame(XX))) # Bug here abline(v=knot, lty=2) X
- p41
par(mfrow=c(3,1)) knots <- c(1:3,5,7,8,10) atx <- seq(0, 11, by=0.1) for(ord in 2:4) { # ord cannot be 1 B <- bs(x=atx, degree=ord-1, knots=knots, intercept=TRUE, Boundary.knots=c(0,11))
# B <- predict(B, seq(0,11, length=101) # works
matplot(atx, B[,1], type="l", ylim=0:1, lty=2) matlines(atx, B[,-1], col=1, lty=1) title(paste("B splines of order", ord)) abline(v=knots, lty=2) }
