Displaying 2 results from an estimated 2 matches for "20x1".
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0x1
2004 Sep 25
2
making custom function compute/return multiple items
...vely new to R. I've read the intro guide, but I
can't quite figure out how to:
I have a function:
Jcost <- function (theta, in, out) {
a <- output - input %*% theta
1/2 * t(a) %*% a
}
where
"theta" is a 2x1 matrix
"in" is a 20x2 matrix
"out" is a 20x1 matrix
return value is a scaler
This works well when I only want to compute given 1 theta matrix. How
do I compute several (say N) 2x1 theta matrices and get back N scaler
values?
Thanks!
--
-david
David Chu
2023 Aug 06
2
Stacking matrix columns
I wish to stack columns of a matrix into one column. The following
matrix command does it. Any other ways? Thanks.
> x<-matrix(1:20,5,4)
> x
???? [,1] [,2] [,3] [,4]
[1,]??? 1??? 6?? 11?? 16
[2,]??? 2??? 7?? 12?? 17
[3,]??? 3??? 8?? 13?? 18
[4,]??? 4??? 9?? 14?? 19
[5,]??? 5?? 10?? 15?? 20
> matrix(x,ncol=1)
????? [,1]
?[1,]??? 1
?[2,]??? 2
?[3,]??? 3
?[4,]??? 4
?[5,]??? 5