Displaying 20 results from an estimated 4000 matches similar to: "dist function in R is very slow"
2017 Jun 18
2
dist function in R is very slow
Hi Stefan,
Thank you very much for pointing me to the wordspace package. It does the job a bit faster than my C code but is 100 times more convenient.
By the way, since the tcrossprod function in the Matrix package is so fast, the Euclidean distance can be computed very fast:
euc_dist <- function(m) {mtm <- Matrix::tcrossprod(m); sq <- rowSums(m*m);? sqrt(outer(sq,sq,"+") -
2017 Jun 18
0
dist function in R is very slow
> By the way, since the tcrossprod function in the Matrix package is so fast, the Euclidean distance can be computed very fast:
Indeed.
> euc_dist <- function(m) {mtm <- Matrix::tcrossprod(m); sq <- rowSums(m*m);  sqrt(outer(sq,sq,"+") - 2*mtm)}
There are two reasons why I didn't use this optimization in "wordspace":
1) It can be inaccurate for small
2012 Jun 16
1
Efficient distance calculation on big matrix
Hi All,
I'm working on analyzing a large data set, lets asume that
dim(Data)=c(1000,8700). I want to calculate the canberra distance
between the columns of this matrix, and using a toy example ('test' is
a matrix filled with random numbers 0-1):
> system.time(d<-as.matrix(dist(t(test), method = "canberra", diag = FALSE, upper = FALSE, p = 2)))
    user   system 
2011 Apr 02
3
Plotting MDS (multidimensional scaling)
Hi,
I just encountered what I thought was strange behavior in MDS. However, it
turned out that the mistake was mine. The lesson learned from my mistake is
that one should plot on a square pane when plotting results of an MDS. Not
doing so can be very misleading. Follow the example of an equilateral
triangle below to see what I mean. I hope this helps others to avoid this
kind of headache.
2010 Jan 21
2
"stack imbalance in ..." when loading a workspace
Hi all,
I just failed in loading a saved wordspace (13MB of size), and received
these errors:
Warning: stack imbalance in 'missing', 52 then 51
Warning: stack imbalance in 'if', 50 then 53
Warning: stack imbalance in 'as.environment', 57 then 59
Warning: stack imbalance in 'ls', 54 then 53
Warning: stack imbalance in '.Internal', 54 then 53
Warning: stack
2012 Sep 04
10
Generic asset definitions and management
(The following is not a Rails-specific question, but relates to a problem 
that affects Rails, so I wonder whether anyone on the team has an opinion 
about it or knows whether a solution is already in development.)
While gem dependencies can be easily managed in a Gemfile by Bundler, when 
it comes to other assets, you either have to manually copy javascript files 
into the app/assets or vendor
2007 Jun 14
3
Responding to a posting in the digest
Is there a convenient way to respond to a particular
posting which is a part of the digest?  
I mean something that will automatically quote the
original message, subject, etc.
Thank you!
Moshe Olshansky
m_olshansky at yahoo.com
2011 Jan 31
1
rgl: draw multiple ellipsoids
Dear list,
I'm trying to visualise some ellipsoidal shapes in 3D. Their position,
axes, and angular orientation can be arbitrary. I saw an ellipse3d
function in rgl; however it is heavily oriented towards the
statistical concept of ellipse of confidence, whilst I am just
concerned with the geometrical object.
Below is my current implementation. It is quite slow when creating
many shapes, so
2008 Jul 10
5
rounding
Hi,
 
Round(0.55,1)=0.5
 
Round(2.55,1)=2.6
 
Can this be right?
 
Thanks,
 
Ed
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2003 Sep 26
2
polar plotting of complex quantities
Hello to everybody,
... and sorry if the question has already been answered.
I am dealing with complex numbers and need a way of plotting them on 
angular plots (2D and 3D). Is there a package that already manage this, 
or can somebody in this R-world who could help me with his skill ?
Thanks to all. Have a nice week-end !
Olivier Eterradossi
Ph.D., "PsychoSensory Properties of
2007 Jun 09
4
Prototype Question
I''m trying to apply a css class to all LI elements that are children
of an element with the ID "idSelector".
This is what I did and it works. But I was wondering if there was an
easier way without having to use an anonymous function?
$$("#idSelector li").each(function()
{ arguments[0].addClassName("myClass") });
Thanks in advance.
2012 Dec 12
3
Fw: regarding plot
Hello,
i am working in origin pro,
i want to plot a graph as like a pdf attached but with black and white lines.
here radial axis varies from 0 to 1. and angular axis from 0 degree to 60 degree.and third axis which is depend on both radial and axial gives non intersecting lines.
how can i read the data from plot for replot.
vikas 
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2008 Aug 24
3
Igraph library: How to calculate APSP (shortest path matrix) matrix for a subset list of nodes.
Dear R Users,
I have a network of 25000 total nodes and a list of 500 node which is a
subset of all nodes. Now I want to calculate the APSP (all pair shortest
path) matrix only for these 500 nodes.
I would appreciate any help.
Thanks in advance
Dinesh
-- 
Dinesh Kumar Barupal
Research Associate
Metabolomics Fiehn Lab
UCD Genome Center
451 East Health Science Drive
GBSF Builidng
University of
2002 Nov 11
3
Wind roses
Are there any R function or packages that generate wind roses?  These are 
``star''-like plots that summarize the frequency, direction and magnigude 
of windspeeds.
Thanks,
Matt 
-- 
Matt Pocernich
University of Colorado - Denver
Department of Mathematics
-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-help mailing list -- Read
2004 Aug 06
1
Fixed-point cos/acos
Hi,
Before I try to code this myself, I'd like to know if anyone has a
fixed-point routine to compute the cos and acos functions. All I need is
around 3-digit accuracy. 
Thanks.
        Jean-Marc
-- 
Jean-Marc Valin, M.Sc.A., ing. jr.
LABORIUS (http://www.gel.usherb.ca/laborius)
Université de Sherbrooke, Québec, Canada
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2017 May 24
2
System Time Source
On Wed, May 24, 2017 10:45 am, Warren Young wrote:
> On May 24, 2017, at 8:52 AM, Chris Adams <linux at cmadams.net> wrote:
>>
>> Once upon a time, Warren Young <warren at etr-usa.com> said:
>>> a. It???s transmitting from a fixed location in a time zone you
>>> probably aren???t in ??? US Mountain ??? being the least populous of
>>> the lower
2008 Nov 17
2
How to calculate the linear distance between 2 points
Deemed colleagues
I would appreciate your help with a sentence to calculate the linear
distance between 2 geographical points (coordinates in UTM).
In advance thnks for your attention,
-- 
Ricardo Bandin Llanos
rbandin@udec.cl
Estudiante - Magíster Cs. m. Pesquerías
Universidad de Concepción, Región del Bio-Bio, Chile
Celular: (0056-41) 97949957
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2007 Aug 07
5
small sample techniques
If my sample size is small is there a particular switch option that I need to use with t.test so that it calculates the t ratio correctly? 
Here is a dummy example?
á =0.05
Mean pain reduction for A =27; B =31 and SD are SDA=9 SDB=12
drgA.p<-rnorm(5,27,9); 
drgB.p<-rnorm(5,31,12)
t.test(drgA.p,drgB.p) # what do I need to give as additional parameter here?
 
I can do it manually but
2004 Jan 06
2
dist(x,y)
Hi Ryszard!
There is a dist function in R.
It's in the mva package.
You can set the kind of distance that you want.
Thanks,
Erin
mailto:hodgess at gator.uhd.edu
2013 Oct 03
1
Random Projection
Hello:
I was wondering, has anyone has encountered an R package that performs random projection/random mapping?  RP is a procedure that is akin to Principal Components Analysis in that it accomplishes dimensionality reduction, but is far more computationally efficient.  I have been searching for some time, but haven't seen anything on CRAN-r yet.  
David Monaghan
Sociology Ph.D. Candidate,