On Jun 24, 2011, at 11:27 AM, Matt Shotwell wrote:
Ravi,
Consider using an environment (i.e. a 'reference' object) to store the
results, avoiding string manipulation, and the potential for loss of
precision:
fr <- function(x, env) { ## Rosenbrock Banana function
x1 <- x[1]
x2 <- x[2]
f <- 100 * (x2 - x1 * x1)^2 + (1 - x1)^2
if(exists('fout', env))
fout <- rbind(get('fout', env), c(x1, x2, f))
So _that's_ what a reference object is?
This seems to give the same results in this example. Am I committing
any sins by sneaking around the get()?
if(exists('fout', env))
fout <- rbind(env[['fout']], c(x1, x2, f)) # seems more direct
Thinking I also might be able to avoid the later assign(), I tried
these without success.
fr <- function(x, env) { ## Rosenbrock Banana function
x1 <- x[1]
x2 <- x[2]
f <- 100 * (x2 - x1 * x1)^2 + (1 - x1)^2
if(exists('fout', env))
env[['fout']] <- rbind(env[['fout']], c(x1, x2, f))
else
fout <- c(x1=x1, x2=x2, f=f)
f
}
out <- new.env()
ans <- optim(c(-1.2, 1), fr, env=out)
out$fout
# NULL
Is there no '[[<-' for environments? (Also tried '<<-' but I know
that is sinful/ )
--
David.
else
fout <- c(x1=x1, x2=x2, f=f)
assign('fout', fout, env)
f
}
out <- new.env()
ans <- optim(c(-1.2, 1), fr, env=out)
out$fout
Best,
Matt
On Fri, 2011-06-24 at 15:10 +0000, Ravi Varadhan wrote:
Thank you very much, Jim. That works!
I did know that I could process the character strings using regex,
but was also wondering if there was a direct way to get this.
Suppose, in the current example I would like to obtain a 3-column
matrix that contains the parameters and the function value:
fr <- function(x) { ## Rosenbrock Banana function
on.exit(print(cbind(x1, x2, f)))
x1 <- x[1]
x2 <- x[2]
f <- 100 * (x2 - x1 * x1)^2 + (1 - x1)^2
f
}
fvals <- capture.output(ans <- optim(c(-1.2,1), fr))
Now, I need to tweak your solution to get the 3-column matrix. It
would be nice, if there was a more direct way to get the numerical
output, perhaps a numeric option in capture.output().
Best,
Ravi.
-------------------------------------------------------
Ravi Varadhan, Ph.D.
Assistant Professor,
Division of Geriatric Medicine and Gerontology School of Medicine
Johns Hopkins University
Ph. (410) 502-2619
email: rvarad...@jhmi.edu
-----Original Message-----
From: jim holtman [mailto:jholt...@gmail.com]
Sent: Friday, June 24, 2011 10:48 AM
To: Ravi Varadhan
Cc: r-help@r-project.org
Subject: Re: [R] How to capture console output in a numeric format
try this:
fr <- function(x) { ## Rosenbrock Banana function
+ on.exit(print(f))
+ x1 <- x[1]
+ x2 <- x[2]
+ f <- 100 * (x2 - x1 * x1)^2 + (1 - x1)^2
+ f
+ }
fvals <- capture.output(ans <- optim(c(-1.2,1), fr))
# convert to numeric
fvals <- as.numeric(sub("^.* ", "", fvals))
fvals
[1] 24.20000000000000 7.09529600000000 15.08000000000000
4.54169600000000
[5] 6.02921600000000 4.45625600000000 8.87993600000000
7.77785600000000
[9] 4.72812500000000 5.16790100000000 4.21000000000000
4.43767000000000
[13] 4.17898900000000 4.32602300000000 4.07081300000000
4.22148900000000
[17] 4.03981000000000 4.89635900000000 4.00937900000000
4.07713000000000
[21] 4.02079800000000 3.99360000000000 4.02458600000000
4.11762500000000
[25] 3.99311500000000 3.97608100000000 3.97108900000000
4.02390500000000
[29] 3.98080700000000 3.95257700000000 3.93217900000000
3.93534500000000
On Fri, Jun 24, 2011 at 10:39 AM, Ravi Varadhan
<rvarad...@jhmi.edu> wrote:
Hi,
I would like to know how to capture the console output from
running an algorithm for further analysis. I can capture this
using capture.output() but that yields a character vector. I
would like to extract the actual numeric values. Here is an
example of what I am trying to do.
fr <- function(x) { ## Rosenbrock Banana function
on.exit(print(f))
x1 <- x[1]
x2 <- x[2]
f <- 100 * (x2 - x1 * x1)^2 + (1 - x1)^2
f
}
fvals <- capture.output(ans <- optim(c(-1.2,1), fr))
Now, `fvals' contains character elements, but I would like to
obtain the actual numerical values. How can I do this?
Thanks very much for any suggestions.
Best,
Ravi.
-------------------------------------------------------
Ravi Varadhan, Ph.D.
Assistant Professor,
Division of Geriatric Medicine and Gerontology School of Medicine
Johns Hopkins University
Ph. (410) 502-2619
email: rvarad...@jhmi.edu<mailto:rvarad...@jhmi.edu>
[[alternative HTML version deleted]]
______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
--
Matthew S. Shotwell
Assistant Professor, Department of Biostatistics
School of Medicine, Vanderbilt University
1161 21st Ave. S2323 MCN Office CC2102L
Nashville, TN 37232-2158
______________________________________________
R-help@r-project.org 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.
David Winsemius, MD
West Hartford, CT
______________________________________________
R-help@r-project.org 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.
