[R] How to efficiently compare each row in a matrix with each row in another matrix?

[arun]

HI Jonathan,

Thanks for the email.

I crosschecked my output with the output generated from the initial solution ("ind").
perhaps <- function(A,B){
nA <- nrow(A)
nB <- nrow(B)
C <-
kronecker(matrix(1,nrow=nA,ncol=1),B) >=
kronecker(A,matrix(1,nrow=nB,ncol=1))
matrix(rowSums(C) == ncol(A), nA, nB, byrow=TRUE)
}

Marius.5.0.Prev <- function(A,B) outer(rowMaxs(A),rowMins(B),'<') #Jonathan function
Marius.5.0 <- function(A,B) outer(rowMaxs(A),rowMins(B),'<=')  #updated Jonathan function
 Marius.4.0<-function(A,B){apply(B,1,function(x) colSums(x>=t(A)))==ncol(A)}
  A <- rbind(matrix(1:4, ncol=2, byrow=TRUE), c(6, 2)) # (3, 2) matrix
  B <- matrix(1:10, ncol=2) # (5, 2
 ind <- apply(B, 1, function(b) apply(A, 1, function(a) all(a <= b))) #original function
 ind
#      [,1]  [,2]  [,3]  [,4]  [,5]
#[1,]  TRUE  TRUE  TRUE  TRUE  TRUE
#[2,] FALSE FALSE  TRUE  TRUE  TRUE
#[3,] FALSE FALSE FALSE FALSE FALSE
 Marius.4.0(A,B)
#      [,1]  [,2]  [,3]  [,4]  [,5]
#[1,]  TRUE  TRUE  TRUE  TRUE  TRUE
#[2,] FALSE FALSE  TRUE  TRUE  TRUE
#[3,] FALSE FALSE FALSE FALSE FALSE
perhaps(A,B)
#      [,1]  [,2]  [,3]  [,4]  [,5]
#[1,]  TRUE  TRUE  TRUE  TRUE  TRUE
#[2,] FALSE FALSE  TRUE  TRUE  TRUE
#[3,] FALSE FALSE FALSE FALSE FALSE

 Marius.5.0(A,B)
#      [,1]  [,2]  [,3]  [,4]  [,5]
#[1,] FALSE  TRUE  TRUE  TRUE  TRUE
#[2,] FALSE FALSE FALSE  TRUE  TRUE
#[3,] FALSE FALSE FALSE FALSE FALSE

Marius.5.0.Prev(A,B)
#      [,1]  [,2]  [,3]  [,4]  [,5]
#[1,] FALSE FALSE  TRUE  TRUE  TRUE
#[2,] FALSE FALSE FALSE FALSE  TRUE
#[3,] FALSE FALSE FALSE FALSE FALSE
A.K.


----- Original Message -----
From: "j2kennel at gmail.com" <j2kennel at gmail.com>
To: smartpink111 at yahoo.com
Cc: 
Sent: Monday, December 10, 2012 5:39 PM
Subject: Re: How to efficiently compare each row in a matrix with each row in another matrix?

Hello Arun,

I saw your message.  For some reason it doesn't let me post on the help site.  It looks like I forgot an equal sign.  It wasn't a problem with the random numbers because there was little chance a number would be repeated.  It should be: 

Marius.5.0 <- function(A,B) outer(rowMaxs(A),rowMins(B),'<=') #Jonathan's code 

However, if you manually look at the example you provided, Marius.4.0 doesn't provide the correct answer either.  There is one too many TRUE values (location [2,3]).  The updated Marius.5.0 gives the correct result.

-Jonathan