Displaying 20 results from an estimated 10000 matches similar to: "Is it possible to vectorize/accelerate this?"
2011 Mar 15
4
Element by element mean of a list of matrices
Hi All,
is there any effiective and dense/compact method to calculate the mean of a list of - of course coincident - matrices on an element by element basis? The resulting matrix' [i, j]-th element is the mean of the list's matrices' [i, j]-th elements respectively...
Iterating by for statement is quite straightforward, but I am seeking for a more elegant solution, and my attempt with
2009 Feb 16
2
solve.QP with box and equality constraints
Dear list,
I am trying to follow an example that estimates a 2x2 markov transition
matrix across several periods from aggregate data using restricted least
squares.
I seem to be making headway using solve.QP(quadprog) as the unrestricted
solution matches the example I am following, and I can specify simple
equality and inequality constraints. However, I cannot correctly specify a
constraint
2013 Jan 24
3
ifelse to speed up loop?
Hello,
I'm not sure how to explain what I'm looking for but essentially I have a
test dataset that looks like this:
test:
V1
1 1
2 1
3 1
4 2
5 2
6 2
7 1
8 1
9 1
10 2
11 2
12 2
And what I want to be able to do is create another column that captures a
"grouping" variable that looks like this:
test
V1 group
1 1 1
2 1 1
3 1 1
4 2 2
5 2
2016 Jan 29
3
Validate Ids Multiple DC
Lol...
I dont know.. and i did learn know most from you :-P
And you have reset the idmap?
Greetz,
.. hihi...
Louis
> -----Oorspronkelijk bericht-----
> Van: samba [mailto:samba-bounces at lists.samba.org] Namens Rowland penny
> Verzonden: vrijdag 29 januari 2016 16:22
> Aan: samba at lists.samba.org
> Onderwerp: Re: [Samba] Validate Ids Multiple DC
>
> On 29/01/16
2016 Aug 01
2
Centos 7 & ntlm
Hihi
So I have a really strange problem. I am running Centos 7 with Samba purely
for ntlm_auth against winbind services (squid/radius auth etc). Its been
working fine till we found a strange bug with the ntlm_auth executable.
If the username has a "w" at the end it throws out a syntax error
see below test:
# ./ntlm_auth --username=lblaauw
username must be specified!
Usage:
2009 Jul 07
3
vectorizing a function
I'm sure I'm missing something obvious but I'm not seeing how to simply
"vectorize" a function of two or more variables.
Say I have
f <- function(x,y) if (x>0) y else -y
Now I have vectors x and y of equal length and I'd like to apply f
element-wise. I.e. conceptually
z <- f(x,y) where x, y, z are vectors of the same length
Some magic involving apply?
2004 Aug 18
5
labeled break statements in R?
Hi,
Are there labeled break statements in R? i.e., something along the
lines of
TOPLOOP: for(i in 1:m) {
for(j in 1:n) {
...
if(condition) {
break TOPLOOP
}
}
}
Thanks,
Roger
2005 Jun 16
5
Vectorization
Greetings,
Can anyone suggest me if we can vectorize the following problem
effectively?
I have two datasets, one dataset is portfolio of stocks returns on a
historical basis and another dataset consist of a bunch of factors (again on
a historical basis). I intend to compute a rolling n-day sensitivitiesfor
each stock for each factor, so the output will be a data frame with
2012 Feb 07
2
Vectorizing a loop
Hello Folks,
I'm trying to vectorize a loop that processes rows of a dataframe. It
involves lots of conditionals, such as "If column 10 == 3, and if column
3 is True, and both column 5 and 6 are False, then set column 4 to True".
So, for example, any ideas about vectorizing the following?
df = data.frame( list(a=c(1,2,3,4),
2011 Mar 29
1
new syntax: bash-like pipe operator
Dear R Community,
One thing that always bugged me about R is the abundance of multi-level nested statements, like:
cumsum(ifelse(c(1,diff(v)),1,0))
because:
a) you have to read them inside out as opposed to left-to-right
b) in the console you always have to go back and type the parenthesis if you want to nest your statement
I kind of like the UNIX pipe operator as a very good abstraction of a
2011 Aug 03
4
slow computation of functions over large datasets
Hello there,
I’m computing the total value of an order from the price of the order items
using a “for” loop and the “ifelse” function. I do this on a large dataframe
(close to 1m lines). The computation of this function is painfully slow: in
1min only about 90 rows are calculated.
The computation time taken for a given number of rows increases with the
size of the dataset, see the example with
2012 Mar 19
3
Issue with asin()
Hello everyone,
I am working for a few days already on a basic algorithm, very common in
applied agronomy, that aims to determine the degree-days necessary for a
given individual to reach a given growth stade. The algorithm (and context)
is explained here: http://www.oardc.ohio-state.edu/gdd/glossary.htm , and
so I implemented my function in R as follows:
DD <- function(Tmin, Tmax, Tseuil,
2010 Nov 01
2
how to save this result in a vector
HI, Dear R community,
I have the following codes to calculate the commulative coverage. I want to
save the output in a vector, How to do this?
test<-seq(10, 342, by=2)
#cover is a vector
cover_per<-function (cover) {
for (i in min(cover):max(cover)) {print(100*sum(ifelse(cover >= i, 1,
0))/length(cover))}
}
result<-cover_per(test)
> result
NULL
Can anyone help me this this?
2013 May 07
4
how to calculate the mean in a period of time?
Hi,
Your question is still not clear.
May be this helps:
dat2<- read.table(text="
patient_id????? t???????? scores
1????????????????????? 0??????????????? 1.6
1????????????????????? 1??????????????? 2.6
1????????????????????? 2???????????????? 2.2
1????????????????????? 3???????????????? 1.8
2????????????????????? 0????????????????? 2.3
2?????????????????????? 2???????????????? 2.5
2001 Nov 16
1
R BATCH mode
hihi
easy!
i would like run r in batch mode. how could i pass through arguments for
my r.script.
for example: r batch my_script.R arg1 arg2
and how must i modify the r script.
wolfgang
--
Wolfgang Mueller Phone +41 1 256-9203,
MeteoSwiss
Kraehbuehlstr. 58, mailto:muw at meteoswiss.ch
CH-8044 Zuerich, Switzerland http://www.meteoswiss.ch/
2001 Nov 15
2
matrices
hihi
i've a matrix say a(30,10,5). how can a function (for example histogram)
be used
to calculate along the first axis, or to create a 10x5 matrix of
histograms?
wolfgang
--
Wolfgang Mueller Phone +41 1 256-9203,
MeteoSwiss
Kraehbuehlstr. 58, mailto:muw at meteoswiss.ch
CH-8044 Zuerich, Switzerland http://www.meteoswiss.ch/
2010 Nov 25
4
Cumsum with a max and min value
I have a vector of values -1, 0, 1, say
a <- c(0, 1, 0, 1, 1, -1, -1, -1, 0, -1, -1)
I want to create a vector of the cumulative sum of this, but I need to set a
maximum and minimum value for the cumsum, for example:
max_value <- 2
min_value <- -2
the expected result would be (0, 1, 1, 2, 2, 1, 0, -1, -1, -2, -2)
The only way I managed to do It, was
res <-
2009 Sep 30
5
Condition to factor (easy to remember)
Dear List,
creating factors in a given non-default orders is notoriously difficult to
explain in a course. Students love the ifelse construct given below most,
but I remember some comment from Martin M?chler (?) that ifelse should be
banned from courses.
Any better idea? Not necessarily short, easy to remember is important.
Dieter
data = c(1,7,10,50,70)
levs =
2007 May 21
2
sequentially process a list
Hi dear R users,
I'm a R beginner and I have a basic question about sequential treatments of lists.
I have a time based (i.e. events are consecutive) list of values of a biological property.
Like :
time value
1 5
2 10
3 7
4 10
5 19
6 21
7 20
8 18
9 10
10 7
11 8
12 12
13 17
14 19
15 24
16 18
17 15
18
2007 Aug 22
3
Help with vector gymnastics
Hello,
What is the best way of solving this problem?
answer <- ifelse(tf=TRUE, i * 5, previous answer)
where as an initial condition
tf[1] <- TRUE
For example if,
tf <- c(T,F,F,F,T,T,F)
over i = 1 to 7
then the output of the function will be
answer = 5 5 5 5 25 30 30
Thank you.
Phil,