Displaying 20 results from an estimated 10000 matches similar to: "Filling NA with cumprod?"
2003 Mar 22
1
cumprod doesn't work with data frames (PR#2667)
Full_Name: J. Sisk
Version: 1.6.1
OS: Linux (RedHat 8)
Submission from: (NULL) (67.119.41.66)
Suppose you make a data-frame like so:
xxx <- data.frame(a=10,b=20,c=30,d=40)
Then
cumprod(xxx[1,])
returns
> cumprod(xxx[1,])
a b c d
1 10 20 30 40
The documentation for cumprod says that it should work on "numerical objects",
and this is a data-frame, but it
2008 Aug 18
2
matrix row product and cumulative product
I spent a lot of time searching and came up empty handed on the
following query. Is there an equivalent to rowSums that does product or
cumulative product and avoids use of apply or looping? I found a rowProd
in a package but it was a convenience function for apply. As part of a
likelihood calculation called from optim, I?m computing products and
cumulative products of rows of matrices with
2011 Nov 27
1
generating a vector of y_t = \sum_{i = 1}^t (alpha^i * x_{t - i + 1})
Dear R-help,
I have been trying really hard to generate the following vector given
the data (x) and parameter (alpha) efficiently.
Let y be the output list, the aim is to produce the the following
vector(y) with at least half the time used by the loop example below.
y[1] = alpha * x[1]
y[2] = alpha^2 * x[1] + alpha * x[2]
y[3] = alpha^3 * x[1] + alpha^2 * x[2] + alpha * x[3]
.....
below are
2012 Oct 18
1
filling NA gaps according to previous data mean and following data mean
Hi everybody,
I have a little problem about filling some gaps of NAs in my data.
These gaps are between nearly constant data (temperature under snow). Here's
a fake example to illustrate how it looks like approximately:
DF <-
data.frame(data=c(-0.51,-0.51,-0.48,-0.6,-0.54,-0.38,-0.6,-0.42,NA,NA,NA,NA,NA,NA,NA,
-0.25,-0.41,-0.5,-0.5,-0.35,-0.7,-1,-0.87))
I would like to replace my NAs
2009 Sep 16
2
Generalized cumsum?
Is there anything like cumsum and cumprod but which allows you to
apply an arbitrary function instead of sum and product? In other words,
I want a function cumfunc(x, f) that returns a vector, so that for all n
up to the length of x
cumapply(x,f)[n] = f(x[1:n])
This would give cumsum and cumprod as special cases when f=sum or
f=prod.
I could write such a function, but I can't see
2011 Jan 27
1
How do I fix this ?
Just when I think I'm starting to learn ....
Statement z1 works, statement z doesn't. Why doesn't z work and what do I do
to fix it ? Clearly the problem is with the first NA, but I would think it's
handled through the loop vectorization.
y1 <- rnorm(20, 0, .013)
y1
[1] -0.0068630836 -0.0101106230 -0.0169663344 -0.0066314769 0.0075063818
[6] -0.0033548024 0.0015647863
2009 Jul 31
1
what meaning missing value True /False needed
This is my code i don't understand the error message:
library(rgenoud)
rm(list=ls())
set.seed(666)
#########################################################
# As a first step, it is assumed that all input parameters are independent of ageingĀ :
#########################################################
InputDim <-20
# Max number of ageings in the inputs
CPIRate <- rep(0.02 , InputDim )
#
2010 Jul 09
3
apply is slower than for loop?
I thought the "apply" functions are faster than for loops, but my most
recent test shows that apply actually takes a significantly longer than a
for loop. Am I missing something?
It doesn't matter much if I do column wise calculations rather than row wise
## Example of how apply is SLOWER than for loop:
#rm(list=ls())
## DEFINE VARIABLES
mu=0.05 ; sigma=0.20 ; dt=.25 ; T=50 ;
2017 Jan 20
1
NaN behavior of cumsum
Hi!
I noticed that cumsum behaves different than the other cumulative functions wrt. NaN values:
> values <- c(1,2,NaN,1)
> for ( f in c(cumsum, cumprod, cummin, cummax)) print(f(values))
[1] 1 3 NA NA
[1] 1 2 NaN NaN
[1] 1 1 NaN NaN
[1] 1 2 NaN NaN
The reason is that cumsum (in cum.c:33) contains an explicit check for ISNAN.
Is that intentional?
IMHO, ISNA would be better
2003 Apr 29
1
Shafer's MIX: Query on code
Thanks to Fernando Tusell and especially to Brian Ripley for
their work on 'mix', leading to an apparently good package
mow available on CRAN.
Going through the R code for the function prelim.mix, I am
wondering why the following method of calculation is used
at one point:
umd <- as.integer(round(exp(cumsum(log(d)))))
(d is a vector containing, in effect, the numbers of levels of
2009 Oct 29
2
fast cumulative matrix multiplication
Hi all,
I am looking for a function like cumprod() that works for matrix
multiplication.
In other words, I have matrices [M1, M2, ..., Mn], and I want to calculate
[M1, M1%*%M2, M1%*%M2%*%M3, ..., M1%*%...%*%Mn] as quickly as possible.
Right now I'm using a for() loop but it seems like there should be a faster
way.
Any help is appreciated!
Thanks,
Todd Schneider
todd.w.schneider@gmail.com
2010 Dec 19
2
Replacing the for loop for time series buid-up
Hi,
is there a function that replaces the following code?
n=200
boot.x[1]=odhad+boot.res[1] #(boot.x[0]=1)
for (j in 1:(n-1)) {
boot.x[j+1]=odhad*boot.x[j]+boot.res[j+1]
}
This is nested in two other loops, and I am looking for some way to improve
code performance
I tried sapply and cumprod but no success.
Thanks
Jan
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2005 Nov 18
2
Image display in R
Hi all,
I am trying to display a matrix of plots(images), for example a 3*3 matrix
of 9 image plots, such that when a user clicks on a image i can show the
enlarged plot. I tried the multiple graphic device(using mfcol=c(3,3) and
mfg), but it creates multiple plots in a single image file. So, i won't be
able to highlight a particular plot when the user clicks on it.
To be more clear, can i
2005 Nov 18
2
Image display in R
Hi all,
I am trying to display a matrix of plots(images), for example a 3*3 matrix
of 9 image plots, such that when a user clicks on a image i can show the
enlarged plot. I tried the multiple graphic device(using mfcol=c(3,3) and
mfg), but it creates multiple plots in a single image file. So, i won't be
able to highlight a particular plot when the user clicks on it.
To be more clear, can i
2010 Nov 09
1
Question related to combination and the corresponding probability
Dear r users,
I have 4 variables x1,x2,x3,x4 and each one has two levels, for example Y
and N.
For x1: prob(Y)=0.6, prob(N)=0.4;
For x2: prob(Y)=0.5, prob(N)=0.5;
For x3: prob(Y)=0.8, prob(N)=0.2;
For x4: prob(Y)=0.9, prob(N)=0.1;
Therefore, the sample space for (x1, x2, x3, x4)={YYYY, YYYN, YYNY,......}
(16 possible combination) and the corresponding probabilities are
{(0.6)(0.5)(0.8)(0.9),
2009 Sep 22
3
Function similar to cumsum/cumprod
Hello, everyone
I wonder if there is in R somewhere a function similar to cumsum().
The function calculates a statistic (say mean or standard deviation)
buy adding consequtively one more data point.
So, say I have a timeseries of 100 observations.
I start by calculating mean of first 30 observations
Then I add one observation and calculate mean of 31 observations
Then I add one more observation
2012 Apr 01
1
Possibly more coefficients?
Hi there,
I have this code:
Prepared_Data <- na.omit(read.csv("Prepared_Data.csv", header=TRUE))
pd <- Prepared_Data[,-3] ## data minus response variable
lev <- sapply(pd,function(x) length(unique(x)))
## total parameters for n variables
par(las=1,bty="l")
plot(cumprod(lev),log="y")
library(Matrix)
m <- sparse.model.matrix(~.^2,data=pd)
ncol(m)
2010 May 05
1
testInstalledBasic question
Hi,
I'm currently in the process of writing an R-installation SOP for my
company. As part of that process I'm using the recommendations from the 'R
Installation and Administration' document, section 3.2, "Testing an
installation". This is done on an XP machine, using the latest binary of
2.11.0.
The binary is downloaded and then installed from the installer. I then
2010 Mar 01
1
function odiag(): assigning values to off-diagonal
hi
I'm trying to use the function odiag(x) for matrix calculations. I would
like to assign new values to an off-diagonal in a matrix.
When I use the diag (x) function I could write something like
p<-matrix(seq(1:12),ncol=4)
p.new<-matrix(rep(0,12),ncol=4)
diag(p.new)<-diag(p)
p.new
But this won't work with odiag. How can I turn odiag (x) into something
like diag (x) in order
2007 Jun 27
1
SEM model fit
I wonder if someone could explain why, when I perform confirmatory
factor-analysis model using polychoric correlations why I do not get an
estimated confidence interval for the RMSEA. My experience with these type
models is that I would obtain a confidence interval estimate. I did not get
any warning messages with the output.
RESULTS:
Model Chisquare = 1374 Df = 185 Pr(>Chisq) = 0