dumpMethods('diag', file='diag.R')
readLines('diag.R')
character(0)
I appreciate the alternative suggested by Ceci Tam, but is this
result a feature or a bug?
More generally, what do you recommend I read to learn about S4
generics? I've read fair portions of Chambers (1998, 2008).
Unfortunately, these produced more frustration than enlightenment for
me. Initially, I did not have access to a version of R with any S4
capabilities. After R acquired those features, there were differences
between the R implementation and Chambers (1998) that I never overcame.
After Chambers (2008) appeared, I found many cases in that book as
well where I could not reproduce the results claimed. I finally gave up
after substantial effort.
I mention this, because it may be related to issues with profound
implications for the future of R. Recently, Jim Ramsay and I added
support for Matrix-class matrices to the "fda" package. In Matlab, that
addition was fairly trivial, Ramsay told me. In R it was surprisingly
difficult, because the Matrix-class objects returned by many of our
revised "fda" generated many errors with existing code that worked fine
with standard dense matrices. To avoid breaking existing code, we added
an argument returnMatrix to many functions with the default being FALSE.
Now if you want to use Matrix-class matrices with "fda", you must
explicitly say "returnMatrix = TRUE" for all the functions with that
argument.
I mention these two together, if many others had experiences with S4
similar to mine, it could help explain why using the Matrix package is
still not transparent to the users, unlike similar features of Matlab.
Thanks,
Spencer
On 6/11/2012 2:45 AM, Ceci Tam wrote:
diag(n) is alright when n = 5e3, it took 0.7 sec on my machine for
diag(5e3). However, it's slow when n = 23000, diag(23000) took 15 sec
On 11 June 2012 17:43, Ceci Tam<yeeching...@gmail.com> wrote:
diag(n) is alright when n = 5e3, it took 0.7 sec on my machine for
diag(5e3). However, it's slow when n = 23000, diag(23000) took 15 sec
On 9 June 2012 06:32, R. Michael Weylandt<michael.weyla...@gmail.com>wrote:
On Fri, Jun 8, 2012 at 5:31 PM, R. Michael Weylandt
<michael.weyla...@gmail.com> wrote:
For the matter and hand, you can probably get to it by simply trying
base:::diag. In this case, it's not too hard because what you're
seeing is the S4 generic that the Matrix package is defining _over_
the regular base function generic.
Sorry -- the regular base function is not a generic in this case.
Everything else still holds though. (Same tricks to find things work
with print which becomes both an S3 and S4 generic on loading Matrix)
More generally, going down the rabbit hole of S4:
As it suggests, first try
showMethods("diag")
and you'll see a long list of types. The parallel to the *.default
method is the one with signature "ANY" so you can try that:
getMethod("diag", "ANY")
which gets you where you need to be.
Hope this helps,
Michael
On Fri, Jun 8, 2012 at 5:11 PM, Spencer Graves
<spencer.gra...@structuremonitoring.com> wrote:
How can one get the source code for diag? I tried the following:
diag
standardGeneric for "diag" defined from package "base"
function (x = 1, nrow, ncol)
standardGeneric("diag")
<environment: 0x0000000009dc1ab0>
Methods may be defined for arguments: x, nrow, ncol
Use showMethods("diag") for currently available ones.
How can I look at the code past the methods dispatch?
methods('diag')
[1] diag.panel.splom
Warning message:
In methods("diag") : function 'diag' appears not to be generic
So "diag" is an S4 generic. I tried the following:
dumpMethods('diag', file='diag.R')
readLines('diag.R')
character(0)
More generally, what do you recommend I read to learn about S4
generics? I've read fair portions of Chambers (1998, 2008), which
produced
more frustration than enlightenment for me.
Thanks,
Spencer
On 6/8/2012 12:07 PM, Uwe Ligges wrote:
I quickly looked at it, and the difference comes from:
n<- 5e3
system.time(x<- array(0, c(n, n))) # from diag()
system.time(x<- matrix(0, n, n)) # from Rdiag()
Replaced in R-devel.
Best,
Uwe Ligges
On 07.06.2012 12:11, Spencer Graves wrote:
On 6/7/2012 2:27 AM, Rui Barradas wrote:
Hello,
To my great surprise, on my system, Windows 7, R 15.0, 32 bits, an R
version is faster!
I was also surprised, Windows 7, R 2.15.0, 64-bit
rbind(diag=t1, Rdiag=t2, ratio=t1/t2)
user.self sys.self elapsed user.child sys.child
diag 0.72 0.080000 0.81 NA NA
Rdiag 0.09 0.030000 0.12 NA NA
ratio 8.00 2.666667 6.75 NA NA
sessionInfo()
R version 2.15.0 (2012-03-30)
Platform: x86_64-pc-mingw32/x64 (64-bit)
locale:
[1] LC_COLLATE=English_United States.1252
[2] LC_CTYPE=English_United States.1252
[3] LC_MONETARY=English_United States.1252
[4] LC_NUMERIC=C
[5] LC_TIME=English_United States.1252
attached base packages:
[1] splines stats graphics grDevices utils datasets methods
[8] base
other attached packages:
[1] fda_2.2.9 Matrix_1.0-6 lattice_0.20-6 zoo_1.7-7
loaded via a namespace (and not attached):
[1] grid_2.15.0 tools_2.15.0
Spencer
Rdiag<- function(n){
m<- matrix(0, nrow=n, ncol=n)
m[matrix(rep(seq_len(n), 2), ncol=2)]<- 1
m
}
Rdiag(4)
n<- 5e3
t1<- system.time(d1<- diag(n))
t2<- system.time(d2<- Rdiag(n))
all.equal(d1, d2)
rbind(diag=t1, Rdiag=t2, ratio=t1/t2)
Anyway, why don't you create it once, save a copy and use it many
times?
Hope this helps,
Rui Barradas
Em 07-06-2012 08:55, Ceci Tam escreveu:
Hello, I am trying to build a large size identity matrix using
diag(). The
size is around 23000 and I've tried diag(23000), that took a long
time.
Since I have to use this operation several times in my program, the
running
time is too long to be tolerable. Are there any alternative for
diag(N)?
Thanks
Cheers,
yct
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______________________________________________
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PLEASE do read the posting guide
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and provide commented, minimal, self-contained, reproducible code.
______________________________________________
R-help@r-project.org mailing list
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and provide commented, minimal, self-contained, reproducible code.
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______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
--
Spencer Graves, PE, PhD
President and Chief Technology Officer
Structure Inspection and Monitoring, Inc.
751 Emerson Ct.
San José, CA 95126
ph: 408-655-4567
web: www.structuremonitoring.com
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