Hi All,
I was looking for a function to find a small matrix inside a larger matrix
in R similar to the one described in the following link:
https://www.mathworks.com/matlabcentral/answers/194708-index-a-small-matrix-in-a-larger-matrix
I couldn't find anything.
The above function can be seen as
On 11/10/2019 6:44 a.m., Morgan Morgan wrote:
Hi All,
I was looking for a function to find a small matrix inside a larger matrix
in R similar to the one described in the following link:
https://www.mathworks.com/matlabcentral/answers/194708-index-a-small-matrix-in-a-larger-matrix
I couldn't fi
On 2019-10-11 04:45, Duncan Murdoch wrote:
On 11/10/2019 6:44 a.m., Morgan Morgan wrote:
Hi All,
I was looking for a function to find a small matrix inside a larger
matrix
in R similar to the one described in the following link:
https://www.mathworks.com/matlabcentral/answers/194708-index
On Fri, 11 Oct 2019 10:45 Duncan Murdoch, wrote:
> On 11/10/2019 6:44 a.m., Morgan Morgan wrote:
> > Hi All,
> >
> > I was looking for a function to find a small matrix inside a larger
> matrix
> > in R similar to the one described in the following link:
> >
> >
> https://www.mathworks.com/matlab
Hi Morgan,
I think there is a discussion on how developers include a function in base
R in another thread:
https://stat.ethz.ch/pipermail/r-devel/2019-October/078551.html
Best,
Jiefei
On Fri, Oct 11, 2019 at 8:19 AM Morgan Morgan
wrote:
> On Fri, 11 Oct 2019 10:45 Duncan Murdoch,
> wrote:
>
Thanks for this interesting suggestion, Morgan. While there is no strict
criteria for base R inclusion, one criterion relevant in this case is that
the usefulness of a feature be proven in the package space first.
Michael
On Fri, Oct 11, 2019 at 5:19 AM Morgan Morgan
wrote:
> On Fri, 11 Oct 20
How do you prove usefulness of a feature?
Do you have an example of a feature that has been added after proving to be
useful in the package space first?
Thank you,
Morgan
On Fri, 11 Oct 2019 13:53 Michael Lawrence,
wrote:
> Thanks for this interesting suggestion, Morgan. While there is no stric
On Fri, Oct 11, 2019 at 3:55 PM Morgan Morgan
wrote:
> How do you prove usefulness of a feature?
> Do you have an example of a feature that has been added after proving to be
> useful in the package space first?
>
> Thank you,
> Morgan
>
The parallel package (a base package like utils, stats, ..
It’s rather difficult. For example, the base R Kendall tau is written with
the naive O(n^2). The much faster O(n log n) implementation was programmed
and is in the pcaPP package. When I say much faster, I mean that my
implementation in Excel VBA was faster than R for 10,000 or so pairs.
R-Core deci
I think you are confusing package and function here. Plus some of the R
Core packages, that you mention, contain functions that should probably be
replaced by functions with better implementation from packages on CRAN.
Best regards
Morgan
On Fri, 11 Oct 2019 15:22 Joris Meys, wrote:
>
>
> On Fr
Perhaps. But aren’t you looking to implementation a function which finds a
submatrix? If I’m confused, please accept my apologies.
Avi
On Fri, Oct 11, 2019 at 10:43 AM Morgan Morgan
wrote:
> I think you are confusing package and function here. Plus some of the R
> Core packages, that you mentio
Using the example in the link here are two one-liners:
A <- c(2,3,4,1,2,3,4,1,1,2)
x <- c(1,2)
# 1 - zoo
library(zoo)
which( rollapply(A, length(x), identical, x, fill = FALSE, align = "left") )
## [1] 4 9
# 2 - Base R using conversion to character
gregexpr(paste(x, collapse = ""
As a package is a collection of functions, and as "base" is not used to
refer to the base package but to all packages that form "base R" (so utils,
graphics, stats, methods, parallel, ...), the functions in the parallel
package are one example of functions incorporated in "base R" from a
package. A
Your answer makes much more sense to me.
I will probably end up adding the function to a package.
Some processes and decisions on how R is developed seems to be obscure to
me.
Thank you
Morgan
On Fri, 11 Oct 2019 15:30 Avraham Adler, wrote:
> It’s rather difficult. For example, the base R Kenda
Also note that the functionality discussed could be regarded as a generalization
of matrix multiplication where * and + are general functions and in this case
we have * replaced by == and + replaced by &.
On Fri, Oct 11, 2019 at 10:46 AM Gabor Grothendieck
wrote:
>
> Using the example in the lin
I pressed return too soon.
If we had such a multiply then
which(embed(A, x) %==.&% reverse(x))
On Fri, Oct 11, 2019 at 10:57 AM Gabor Grothendieck
wrote:
>
> Also note that the functionality discussed could be regarded as a
> generalization
> of matrix multiplication where * and + are gene
Has someone looked into the image processing area for this? That sounds
a little bit too high-level for base R to me (and I would be surprised
if any mainstream programming language had this kind of functionality
built-in).
H.
On 10/11/19 03:44, Morgan Morgan wrote:
> Hi All,
>
> I was lookin
The link you posted used the same inputs as in my example. If that is
not what you meant maybe
a different example is needed.
Regards.
On Fri, Oct 11, 2019 at 2:39 PM Pages, Herve wrote:
>
> Has someone looked into the image processing area for this? That sounds
> a little bit too high-level for
Basically the problem is to find the position of a submatrix inside a
larger matrix. Here are some links describing the problem:
https://stackoverflow.com/questions/10529278/fastest-way-to-find-a-m-x-n-submatrix-in-m-x-n-matrix
https://stackoverflow.com/questions/16750739/find-a-matrix-in-a-big-m
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