[R] Help on looping problem needed!
I am wondering if someone could help me out with following problem:
I have written a for loop which generates a random normal distribution
let us say 1000 times.
When the restriction is met (mean0.01), the loop stops, prints
the mean value and plots a histogram.
for(i in 1:1000) {
a-rnorm(1000,0,.2)
b-abs(mean(a))
if(b.01) next else {print(b);hist(a);break}}
How to reshape the loop when I want to find at least 5 distibutions
that meet my restriction and save them (assign) under
names R1R5.
Could you help me please?
Michael
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Re: [R] Help on looping problem needed!
try this:
tol - 0.01
mat - matrix(as.numeric(NA), 1000, 5)
k - 1
while(any(is.na(mat))){
x - rnorm(1000, sd = 0.02)
if (abs(mean(x)) tol) {
mat[, k] - x
k - k + 1
}
}
abs(colMeans(mat))
par(mfrow = c(2, 3))
apply(mat, 2, hist)
I hope it helps.
Best,
Dimitris
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven
Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://med.kuleuven.be/biostat/
http://www.student.kuleuven.be/~m0390867/dimitris.htm
- Original Message -
From: Ing. Michal Kneifl, Ph.D. [EMAIL PROTECTED]
To: Rhelp r-help@stat.math.ethz.ch
Sent: Monday, July 23, 2007 4:40 PM
Subject: [R] Help on looping problem needed!
I am wondering if someone could help me out with following problem:
I have written a for loop which generates a random normal
distribution
let us say 1000 times.
When the restriction is met (mean0.01), the loop stops, prints
the mean value and plots a histogram.
for(i in 1:1000) {
a-rnorm(1000,0,.2)
b-abs(mean(a))
if(b.01) next else {print(b);hist(a);break}}
How to reshape the loop when I want to find at least 5 distibutions
that meet my restriction and save them (assign) under
names R1R5.
Could you help me please?
Michael
__
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm
__
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] Help for looping
Please try to give a simple reproducible example and simplify your codes
a bit if you want to get useful responses.
For example, you say your data is a matrix of 1000*30, where I presume
the matrix has 1000 rows and 30 columns. If so EMP - data[,378:392]
does not make sense.
Perhaps you might be interested in knn() in the class package.
Regards, Adai
[EMAIL PROTECTED] wrote:
Rusers:
I have tried to minimize computing times by taking advanage of
lapply(). My data is a 1000*30 matrix and the distance matrix was
created with dist(). What I am trying to do is to compute the standard
distances using the frequencies attached to the nearest negibors of n
reference zones. So I will have 1000 standard distances, and would like
to see the frequency distribution of the standard distances.
# Convert decimal degrees into UTM miles
x-(data[,1]-58277.194363)*0.000621
y-(data[,2]-4414486.03135)*0.000621
# Combine x y for computing distances
coords-cbind(x,y)
pts-length(data)
# Subset housing data and employment data
RES-data[,3:17]
EMP-data[,378:392]
# Combine all the subdata as D
D-cbind(coords,RES,EMP)
cases-ncol(D)-ncol(coords)
# Create a threshold bandwidth for defining the nearest neighbors
thrs-seq(0,35,by=1)
SDTAZ-rep(list(matrix(,nrow(D),length(thrs))),cases)
for (j in 1:nrow(D))
for (k in 1:length(thrs))
for (l in 1:cases)
{
{
{
SDTAZ[[l]][j,k]-
sqrt(
sum(
(D[as.vector(which(dis[j,]=thrs[k])),l+2]-D[j,l+2]-
min(D[as.vector(which(dis[j,]=thrs[k])),l+2]-D[j,l+2])+1)*
(
(dis[j,as.vector(which(dis[j,]=thrs[k]))])^2
)
)
/sum(D[as.vector(which(dis[j,]=thrs[k])),l+2]-D[j,l+2]-
min(D[as.vector(which(dis[j,]=thrs[k])),l+2]-D[j,l+2])+1)
)
}
}
}
I think that within this nested loop, I should use lapply() but I ended
up getting different values I appreciate if someone could kindly
help me.
Thank you very much.
Takatsugu Kobayashi
PhD Candidate
Indiana University, Dept. Geography
__
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
__
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] Help for looping
Rusers:
I have tried to minimize computing times by taking advanage of
lapply(). My data is a 1000*30 matrix and the distance matrix was
created with dist(). What I am trying to do is to compute the standard
distances using the frequencies attached to the nearest negibors of n
reference zones. So I will have 1000 standard distances, and would like
to see the frequency distribution of the standard distances.
# Convert decimal degrees into UTM miles
x-(data[,1]-58277.194363)*0.000621
y-(data[,2]-4414486.03135)*0.000621
# Combine x y for computing distances
coords-cbind(x,y)
pts-length(data)
# Subset housing data and employment data
RES-data[,3:17]
EMP-data[,378:392]
# Combine all the subdata as D
D-cbind(coords,RES,EMP)
cases-ncol(D)-ncol(coords)
# Create a threshold bandwidth for defining the nearest neighbors
thrs-seq(0,35,by=1)
SDTAZ-rep(list(matrix(,nrow(D),length(thrs))),cases)
for (j in 1:nrow(D))
for (k in 1:length(thrs))
for (l in 1:cases)
{
{
{
SDTAZ[[l]][j,k]-
sqrt(
sum(
(D[as.vector(which(dis[j,]=thrs[k])),l+2]-D[j,l+2]-
min(D[as.vector(which(dis[j,]=thrs[k])),l+2]-D[j,l+2])+1)*
(
(dis[j,as.vector(which(dis[j,]=thrs[k]))])^2
)
)
/sum(D[as.vector(which(dis[j,]=thrs[k])),l+2]-D[j,l+2]-
min(D[as.vector(which(dis[j,]=thrs[k])),l+2]-D[j,l+2])+1)
)
}
}
}
I think that within this nested loop, I should use lapply() but I ended
up getting different values I appreciate if someone could kindly
help me.
Thank you very much.
Takatsugu Kobayashi
PhD Candidate
Indiana University, Dept. Geography
__
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
