Displaying 20 results from an estimated 5000 matches similar to: "using mapply to avoid loops"
2011 Jul 11
1
plot means ?
Hi,
I need this plot:
given: x,y - numerical vectors of length N
plot xi vs mean(yj such that |xj - xi|<epsilon)
(running mean?)
alternatively, discretize X as if for histogram plotting and plot mean y
over the center of the histogram group.
is there a simple way?
thanks!
--
Sam Steingold (http://sds.podval.org/) on CentOS release 5.6 (Final) X 11.0.60900031
http://thereligionofpeace.com
2008 Aug 27
2
r function for calculating extreme spread in group
I'm trying to figure out how to write a r function that will calculate
the extreme spread of a group of points given their (x,y)
coordinates. Extreme Spread is the maximal Euclidean distance between
two points in a group
ex.spread = max{ sqrt [ (xi-xj)^2 - (yi-yj)^2 ] } for i not equal to j
I have 60 levels to apply this to.
There is the combination function in the dprep package but
2001 Nov 21
2
distances from points to line
Dear all,
I have discovered that there are many things that I used to do in my GIS
which are easily done directly in R, for example calculating interpoint
distances using geoR and pick out points inside a polygon using splancs.
I now wonder, is there a function to create a line object like a
watercourse and then calculate the distances between many points in space
and this line?
I couldn't
2005 Nov 04
2
Simplify iterative programming
Dear,
I am looking for the simplification of a formula to improve the
calculation speed of my program. Therefore I want to simplify the
following formula:
H = sum{i=0..n-1 , [ sum {j=0..m-1 , sqrt ( (Ai - Bj)^2 + (Ci -
Dj)^2) } ] }
where:
A, C = two vectors (with numerical data) of length n
B, D = two vectors (with numerical data) of length m
sqrt = square root
Ai = element of A with index
2009 Jul 16
1
Theil test help
Hello,
I have a series of questions that I hope will be simple to answer. Basically I would like a code to do the following so that I can compute the distribution free test for the slope of a postulated regression line (Theil test). As I am testing the null hypothesis that slope = 0 against the general alternative the slope does not equal 0, it should be pretty straight-forward.
I have a data
2011 Oct 18
1
Repeat a loop until...
Dear all,
I know there have been various questions posted over the years about loops but I'm afraid that I'm still stuck. I am using Windows XP and R 2.9.2.
I am generating some data using the multivariate normal distribution (within the 'mnormt' package). [The numerical values of sanad and covmat are not important.]
> datamat <-
2009 Dec 04
1
Saving predict
Hi all,,Im using function arima()
I.e
series is my data
model<-arima(series,c(1,0,0))
forecast<-predict(model,80)
I want to create a variable:
b1<-forecast$pred - 1.96*forecast$se
and save in a txt file
but using this:
save(b1, file= "b1.txt")
creates afile butwith this inside:
]{HQ ~|LJIiW*-l)% )m#),
RIiSfdbGur9p94; H"L#Rez
1y3pN8{,I6W!6=
{6l?OMw_5KZ+
=
2006 Jan 11
1
F-test degree of freedoms in lme4 ?
I have a problem moving from multistratum aov analysis to lmer.
My dataset has observations of ampl at 4 levels of gapf and 2 levels of bl
on 6 subjects levels VP, with 2 replicates wg each, and is balanced.
Here is the summary of this set with aov:
>> summary(aov(ampl~gapf*bl+Error(VP/(bl*gapf)),hframe2))
>
>Error: VP
> Df Sum Sq Mean Sq F value Pr(>F)
>Residuals
2011 Dec 02
1
1.6x speedup for requal() function (in R/src/main/unique.c)
Hi,
FWIW:
/* Taken from R/src/main/unique.c */
static int requal(SEXP x, int i, SEXP y, int j)
{
if (i < 0 || j < 0) return 0;
if (!ISNAN(REAL(x)[i]) && !ISNAN(REAL(y)[j]))
return (REAL(x)[i] == REAL(y)[j]);
else if (R_IsNA(REAL(x)[i]) && R_IsNA(REAL(y)[j])) return 1;
else if (R_IsNaN(REAL(x)[i]) && R_IsNaN(REAL(y)[j])) return 1;
2011 Feb 09
2
Generate multivariate normal data with a random correlation matrix
Hi All.
I'd like to generate a sample of n observations from a k dimensional
multivariate normal distribution with a random correlation matrix.
My solution:
The lower (or upper) triangle of the correlation matrix has
n.tri=(d/2)(d+1)-d entries.
Take a uniform sample of n.tri possible correlations (runi(n.tr,-.99,.99)
Populate a triangle of the matrix with the sampled correlations
Mirror the
2008 Jul 01
1
[.data.frame speedup
Below is a version of [.data.frame that is faster
for subscripting rows of large data frames; it avoids calling
duplicated(rows)
if there is no need to check for duplicate row names, when:
i is logical
attr(x, "dup.row.names") is not NULL (S+ compatibility)
i is numeric and negative
i is strictly increasing
"[.data.frame" <-
function (x, i, j,
2011 Oct 06
1
sum of functions
Dear all,
I would like to create a code for semiparametric Klein and Spady's
estimator. For that I created a function that provides the log-likelihood
function for each observation (so it is a function of betas and i, where i
denotes the observation). Now, in order to maximize the log-likelihood
function, I have to sum these log-likelihood functions for each i and so to
get another function
2008 Oct 02
3
Adding plane in a 3D scatterplot
I have drawn a 3D scatter plot :
library(mnormt)
library(scatterplot3d)
dat = cbind(rmnorm(3, rep(0,2), diag(2)), 1:3)
scatterplot3d(dat)
Now I want to do 2 things :
1 : In the Z-axis (i.e. height), I want to see only numbers 1,2,3, etc NOT, 1,1.5,2,2.5.............
2. I want to add two Horizontal planes at hight z=2 and z=3. Those two planes should look like "bottom" of that 3D plot
2004 May 24
1
as.matrix.data.frame() in R 1.9.0 converts to character when it should (?) convert to numeric
Conversion of a data frame to a matrix using as.matrix() when a
column of the data frame is POSIXt and all other columns are numeric
has changed in R 1.9.0 from R 1.8.1. The new behavior issues a
warning message and converts to a character matrix. In R 1.8.1, such
an object was converted to a numeric matrix.
Here is an example.
#### R 1.9.0 ####
> foo <- data.frame(
2017 Dec 01
1
Bug is as.matrix.data.frame with nested data.frame
Converting a data.frame with a nested data.frame to a matrix fails:
x <- structure(list(a = data.frame(letters)),
class = "data.frame",
row.names = .set_row_names(26))
as.matrix(x)
#> Error in ncol(xj) : object 'xj' not found
The offending code is here, in the definition of as.matrix.data.frame
(source/base/all.R):
for (j in pseq) {
2001 Dec 11
0
VirtualProtect and app crash: what's your interpretation?
Here is my thought process on why the application crashes with a
protection violation reading a section of memory.
I used IDA to disassemble the app. Here's the section where it reads
from memory and crashes because of a protection violation:
00760D4A sub_760D4A proc near ; CODE XREF:
sub_75FCB0+159^Xp
00760D4A push ebp
00760D4B mov
2009 Oct 29
3
Weird error: Error in xj[i] : invalid subscript type 'list'
I got the error. I haven't been able to get a stand along case so that
I can show it here. But could somebody give some clue on what could
cause this error? Since I never defined xj[i], I don't understand
where this error come from.
Error in xj[i] : invalid subscript type 'list'
2011 May 16
2
about spearman and kendal correlation coefficient calculation in "cor"
Hi,
I have the following two measurements stored in mat:
> print(mat)
[,1] [,2]
[1,] -14.80976 -265.786
[2,] -14.92417 -54.724
[3,] -13.92087 -58.912
[4,] -9.11503 -115.580
[5,] -17.05970 -278.749
[6,] -25.23313 -219.513
[7,] -19.62465 -497.873
[8,] -13.92087 -659.486
[9,] -14.24629 -131.680
[10,] -20.81758 -604.961
[11,] -15.32194 -18.735
To calculate the ranking
2003 Jun 18
1
suggestion for make.names
I would like to suggest a modification to the make.names() function.
The current implementation has two problems:
1. It doesn't check if a name matches an R keyword (like "function").
2. The uniqueness algorithm is not invariant to concatenation.
In other words,
make.names(c("a","a","a"),unique=T) !=
2003 Jun 18
1
suggestion for make.names
I would like to suggest a modification to the make.names() function.
The current implementation has two problems:
1. It doesn't check if a name matches an R keyword (like "function").
2. The uniqueness algorithm is not invariant to concatenation.
In other words,
make.names(c("a","a","a"),unique=T) !=