Displaying 20 results from an estimated 5000 matches similar to: "cumprod doesn't work with data frames (PR#2667)"
2012 May 25
1
Filling NA with cumprod?
Hello,
I need to build certain interpolation logic using R. Unfortunately, I just
started using R, and I'm not familiar with lots of advanced or just
convenient features of the language to make this simpler. So I struggled
for few days and pretty much reduced the whole exercise to the following
problem, which I cannot resolve:
Assume we have a vector of some values with NA:
a <- c(1,
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
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
2013 Jul 31
1
[Announcement] Linux Plumbers ACPI/PM, PCI Microconference
On Wednesday, July 31, 2013 10:35:05 AM Shuah Khan wrote:
> On Wed, Jul 31, 2013 at 5:40 AM, Rafael J. Wysocki <rjw at sisk.pl> wrote:
> > Hi All,
> >
> > The original announcement didn't go to linux-pm, so again:
> >
> > On Tuesday, July 16, 2013 08:21:26 PM Myron Stowe wrote:
> >> Linux Plumbers has approved an ACPI/PM, PCI microconference. The
2013 Jul 31
1
[Announcement] Linux Plumbers ACPI/PM, PCI Microconference
On Wednesday, July 31, 2013 10:35:05 AM Shuah Khan wrote:
> On Wed, Jul 31, 2013 at 5:40 AM, Rafael J. Wysocki <rjw at sisk.pl> wrote:
> > Hi All,
> >
> > The original announcement didn't go to linux-pm, so again:
> >
> > On Tuesday, July 16, 2013 08:21:26 PM Myron Stowe wrote:
> >> Linux Plumbers has approved an ACPI/PM, PCI microconference. The
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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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
2012 Jul 27
1
C code validation
Dear R-devel,
I'm trying to validate the results from a C function, against a (trial
and tested) older R function. For reasons unknown to me, the C
function seems to give different result sometimes at each trial, even
with the very same data.
These are the relevant outputs from R:
> library(QCA)
Loading required package: lpSolve
> benchmark <- function(x, y) {
+ index <- 0
2012 Dec 17
2
Suggestion: 'method' slot for format.ftable()
Dear R-developers,
I would like to suggest a 'method' slot for format.ftable() (see an adjusted
'format.ftable()' below, taken from the source of R-2.15.2).
At the moment, format.ftable() contains several empty cells due to the way the
row and column labels are printed. This creates problems (= unwanted empty
columns/rows) when converting an ftable to a LaTeX table; see an
2006 Feb 28
2
vector math: calculating a rolling 12 row product?
I have a dataframe of numeric values with 30 ?rows?
and 7 ?columns?.
For each column, beginning at ?row? 12 and down to
?row? 30, I wish to calculate the ?rolling 12 row
product?. I.e., within each column, I wish to
multiply all the values in row 1:12, 2:13,
19:30.
I wish to save the results as a new dataframe, which
will have 19 rows and 7 columns.