18/09/14 07:47:53.11 IOEu7JkF.net
foo <- function(a,b,c){
gr=expand.grid(1:a,1:b)
c2=(1:c)^2
f = function(x,y) (x<y) & (x^2+y^2) %in% c2
i=which(mapply(f,gr[,1],gr[,2]))
ab=as.matrix(gr[i,])
cbind(ab,sqrt(ab[,1]^2+ab[,2]^2))
}
foo(20,20,20)
a=20;b=20;c=20
gr=expand.grid(1:a,1:b,1:c)
f = function(a,b,c) a<b & a^2+b^2==c^2
i=which(mapply(f,gr[,1],gr[,2],gr[,3]))
gr[i,]