I want to calculate the projection u⟶v
Definition: proj(u⟶v)=u⋅v|v|2v
# my 2 vectors
u<-c(1.5,sqrt(3)/2)
v<-c(2,0)
The answer should look as the following :
[1] 1.5 0.0
2 Answers
Not entirely sure what you are looking for.
u <- c(1.5,sqrt(3)/2)
v <- c(2,0)
as.vector( (u %*% v) / (v %*% v) ) * v
yields
[1] 1.5 0.0
You can wrap it into a function
proj <- function(u, v) {
return(as.vector( (u %*% v) / (v %*% v) ) * v)
}
An alternative approach:
library(mosaic)
u <- c(1.5,sqrt(3)/2)
v <- c(2,0)
project(u, v)
# 1.5 0.0
vlength(u)
# 1.732051
vlength(v)
# 2
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