[R] Fast Matrix Computation

[David Neu]

Thanks to everyone who responded!

On Sun, May 23, 2010 at 1:32 AM, Jorge Ivan Velez
<jorgeivanvelez at gmail.com> wrote:
> Yes, it should be. Thank you for pointing that out. Apologies for the noise.
>
> Regards,
> Jorge
>
>
> On Sun, May 23, 2010 at 1:07 AM, Berend Hasselman <> wrote:
>
>>
>>
>> Jorge Ivan Velez wrote:
>> >
>> > # The same using a function foo
>> > foo <- function(A, B){
>> >   rA <- 1:nrow(A)
>> >   rB <- 1:nrow(B)
>> >   grid <- as.matrix(expand.grid(rA, rB))
>> >   t(apply(grid, 1, function(x) abs(A[x[1], ] - B1[x[2], ])))
>> >  }
>> >
>> > foo(A, B)
>> > foo(A, B1)
>> >
>> > As usual, there might be better and faster ways to do this.
>> >
>> > HTH,
>> > Jorge
>> >
>>
>> Shouldn't the B1 in the last line of the function 'foo' be B (the second
>> argument of the function)?
>>
>> Berend
>> --
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>>
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>
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