Displaying 4 results from an estimated 4 matches for "paleologo".
2008 Aug 06
4
Union of columns of two matrices
...t; (=fast & short) function that
returns a matrix with all and only the non-duplicated columns of both
matrices; the column order does not matter. In essence, a matrix equivalent
of union(x,y), where x and y are vectors. I could not come with anything
nice. Any ideas?
Giuseppe
--
Giuseppe A. Paleologo :: Email: paleologo@gmail.com :: AOL: gappy3000 ::
Skype :: gappy3000 :: Gtalk: paleologo :: Mobile: 917.331.3497
fact: 2^32,582,657-1 is a prime
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2008 May 08
2
speeding up a special product of three arrays
I am struggling with R code optimization, a recurrent topic on this list.
I have three arrays, say A, B and C, all having the same number of columns.
I need to compute an array D whose generic element is
D[i, j, k] <- sum_n A[i, n]*B[j, n]*C[k, n]
Cycling over the three indices and subsetting the columns won't do. Is there
any way to implement this efficiently in R or should I resign to
2006 Jun 23
3
problem installing gsl package under Ubuntu Breezy Badger
I am trying to install the gls package (a wrapper for GNU scientific library
special functions) package under Ubuntu 5.10. I have gls-bin (the debian GNU
Scientific Library binary package). When I try to install the R package, I
receive the following.
> install.packages("gsl",dependencies=T)
Warning in install.packages("gsl", dependencies = T) :
argument
2008 Aug 27
1
A manipulation problem for a large data set in R
I have two questions for the group. One is very concrete, and is dangerously
close to a "please do my homework" posting. The second follows from the
first one but is more general. I would welcome the advice of experienced R
users.
As for the first one: I have a data frame with two variables
X Y
A, chris
D, chris
B, chris
B, chris
C, andrew
E, andrew
C, andrew
B, beth