17/10/20 14:30:53.07 hxLmqOB4.net
## 位数２ｎの二面体群の演算表を作る
# D2n( e,d1,d2,d3,..,dn-1, t,td,td2,td3,...,tdn-1)
n=7
tikan <- function(X,Y=.Y){ # e.g. c(1,2,3) -> .Y=c(2,1,3)
n=length(X)
Z=rep(NA,n)
I=1:n
for(i in 1:n){
j <- which(I==X[i])
Z[i] <- Y[j]
}
return(Z)
}
tikan2 <- function(X,Y){ # replace Y first then X
n=length(X)
Z=rep(NA,n)
I=1:n
for(i in 1:n){
j <- which(I==X[i])
Z[i] <- Y[j]
}
return(Z)
}
equal <- function(x,y) sum((x-y)^2)==0