Very interesting - thanks! Most of my problems are not limited by
compute speed, but its clear that for some sorts of compute-intensive
problems, sweep might be a limiting approach.
On 2/29/2024 6:12 PM, Richard M. Heiberger wrote:
> I decided to do a direct comparison of transpose and sweep.
>
I added two more rows
library(microbenchmark)
NN <- matrix(c(1, 2, 3, 4, 5, 6), nrow = 2, byrow = TRUE) # Example matrix
lambda <- c(2, 3, 4) # Example vector
colNN <- t(NN)
matlam <- matrix(lambda, byrow=TRUE, nrow=2, ncol=3)
microbenchmark(
sweep = sweep(NN, 2, lambda, "/"),
transpos
Dear Ivan,
Thank you very much for this interesting information.
Regarding:
"For well-behaved packages that declare their dependencies correctly,
parsing the NAMESPACE for importFrom() and import() calls should give
you the explicit imports."
I did learn something new (I am not very experienced
I decided to do a direct comparison of transpose and sweep.
library(microbenchmark)
NN <- matrix(c(1, 2, 3, 4, 5, 6), nrow = 2, byrow = TRUE) # Example matrix
lambda <- c(2, 3, 4) # Example vector
colNN <- t(NN)
microbenchmark(
sweep = sweep(NN, 2, lambda, "/"),
transpose = t(t(NN)/la
The build system rolled up R-4.3.3.tar.gz and .xz (codename "Angel Food Cake")
this morning.
This is a minor update, intended as the wrap-up release for the 4.3.x series.
This also marks the 6th anniversary of R-1.0.0. (2000-02-29)
The list below details the changes in this release.
You can
Thanks to all. Great ideas. I found Eik Vettorazzi's suggesstion easy to
implrment:
ebarm<-vbarm<-NULL
...
if (is.null(ebarm)) ebarm<-ame.00$ei/k else ebarm<-ebarm+ame.00$ei/k
if (is.null(vbarm)) vbarm<-ame.00$vi/k else vbarm<-vbarm+ame.00$vi/k
...
Steven Yen
On 2/29/2024 10:31 PM, Ebert,Timo
You could declare a matrix much larger than you intend to use. This works with
a few megabytes of data. It is not very efficient, so scaling up may become a
problem.
m22 <- matrix(NA, 1:60, ncol=6)
It does not work to add a new column to the matrix, as in you get an error if
you try m22[ ,
x <- numeric(0)
for (...) {
x[length(x)+1] <- ...
}
works.
You can build a matrix by building a vector one element at a time this way,
and then reshaping it at the end. That only works if you don't need it to be
a matrix at all times.
Another approach is to build a list of rows. It's not a ma
Dear Steven,
I used "sample" just to generate a non-trivial example, you could insert
your code of generating the real xi at this point :-)
If you want to stick to for-loops for some reasons, something like this
could work
x<-NULL
for (i in 1:5){
xi<-1:5
if (is.null(x)) x<-xi else x<-x+
Hello Eik:
Thanks. I do not need to sample. Essentially, I have a do loop which
produces 24 vectors of length of some length (say k=300) and 24 matrices
of 300x300. Then, I simply need to take the averages of these 24
vectors and matrices:
x=(x1+x2+...+x24)/k
y=(y1+y2+...+y24)/k
I am just
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