Displaying 20 results from an estimated 2000 matches similar to: "Constrained fits: y~a+b*x-c*x^2, with a,b,c >=0"
2007 Dec 05
1
Quadratic programming
Hi,
I'm quite new at R and I haven't found the answer to my question anywhere on the net, so either it is trivial or not documented. So, bare with be.
I am using the quadprog package and its solve.QP routine to solve and quadratic programming problem with inconsistent constraints, which obviously doesn't work since the constraint matrix doesn't have full rank. A way to solve this
2008 Jul 16
1
NAMESPACE vs internal.Rd
Hi the list,
When we use package.skeleton, it create some file in the man
directorie. - If we use package.skeleton with namespace=FALSE, it
create a file toto-internal.Rd
- If we use package.skeleton with namespace=TRUE, it does not create
the file toto-internal.Rd
Why is that ?
Christophe
2008 Oct 29
2
definition of a function
Hello, R subscribers.
I would like to define a function like this one:
Fun <- function(x) sin(x)/x
with value 1 at x=0. How can I do that?
Is there a way to plot it "symbolically", without using x as a vector?
e.g.
x <- seq(from=-10, to=10, length=100)
plot(x, Fun(x))
Thank you in advance.
2009 Feb 22
2
How to reshape this data frame from long to wide ?
I tried cast and melt in reshape package, but still can't convert this data
frame m
m
[,1] [,2]
[1,] "A" "1"
[2,] "A" "2"
[3,] "B" "3"
to this form.
m1
[,1] [,2]
[1,] "A" "B"
[2,] "1" "3"
[3,] "2" NA
Please help.
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2008 Dec 05
3
Logical inconsistency
Dear colleagues
Please could someone kindly explain the following inconsistencies I've discovered when performing logical calculations in R:
8.8 - 7.8 > 1
> TRUE
8.3 - 7.3 > 1
> TRUE
Thank you,
Emma Jane
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2008 Feb 15
2
Quadratic Programming
Hi,
I am using solve.QP (from quadprog) to solve a standard quadratic
programming problem: min_w -0.5*w'Qw st ... I would like solve.QP to do two
things: 1) to start the optimization from a user-supplied initial
condition; i.e., from a vector w_0 that satisfies the constraints, and 2) to
return the values of the lagrange multiplieres associated with the
constraints. I did not find an obvious
2008 Dec 02
1
r2 for lm() with zero intercept
Hello list
I'm a little confused about the R2 and adjusted R2 values reported by lm() when I try to fix an intercept. When using +0 or -1 in the formula I have found that the standard error generally increases (as I would expect) but the R2 also increases
(which seems counter intuitive). I've pasted a short test script below to illustrate. I do realise that many will say I shouldn't be
2008 Dec 01
2
Warning: missing text for item ... in \describe?
Hello:
What might be the problem generating messages like "Warning:
missing text for item ... in \describe" with "R CMD check" and "R CMD
install"?
With the current version of "fda" on R-Forge, I get the following:
Warning: missing text for item 'fd' in \describe
Warning: missing text for item 'fdPar' in \describe
2009 May 25
2
inconsistency in ?factor
In the almost current development version (2009-05-22 r48594) and also in
https://svn.r-project.org/R/trunk/src/library/base/man/factor.Rd
?factor contains (compare the formulations marked by ^^^^^^)
\section{Warning}{
The interpretation of a factor depends on both the codes and the
\code{"levels"} attribute. Be careful only to compare factors with
the same set of levels (in
2009 Apr 27
2
The .tex version of the manual in foo.Rcheck
In version 2.8.1, running Rcmd check on the package foo would leave the file foo-manual.tex in the folder foo.Rcheck.
But as of 2.9.0 only foo-manual.pdf and foo-manual.log are there.
Is this intentional?
Anyway it is inconvenient, because I would occasionally like to include the manual at the end of a set of exercises, and this was a convenient file to \input with a few select %'s added.
2008 Feb 13
3
indices of rows containing one or more elements >0
Hi,
Given test <- matrix(c(0,2,0,1,3,5), 3,2)
> test[test>0]
[1] 2 1 3 5
These are values >0
> which(test>0)
[1] 2 4 5 6
These are array indices of those values >0
> which(apply(test>0, 1, all))
[1] 2
This gives the row whose elements are all >0
I can't seem to get indices of rows containing one or more elements >0
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2009 Mar 26
1
Bug? FORTTRAN help
I was feeling masochistic the other day and we have been having some wierd memory problems so I started digging into the source for L-BFGS-B. In the lbgfsb.c file I see the following code:
/* Cholesky factorization of (2,2) block of wn. */
F77_CALL(dpofa)(&wn[*col + 1 + (*col + 1) * wn_dim1], &m2, col, info);
if (*info != 0) {
*info = -2;
return;
}
If I am not mistaken
2007 Dec 06
1
Solve.QP
Hi there,
I have a major problem (major for me that is) with solve.QP and I'm new at this. You see, to solve my quadratic program I need to have the lagrange multipliers after each iteration. Solve.QP gives me the solution, the unconstrained solution aswell as the optimal value. Does anybody have an idea for how I could extract the multipliers?
Thanx,
Serge
"Beatus qui prodest quibus
2008 Mar 12
1
Problem when calling FORTRAN subroutine (dll)
Hello,
I am trying to call a FORTRAN subroutine from R. The Fortran code is @:
http://lib.stat.cmu.edu/apstat/206
It performs a bivariate isotonic regression on a rectangular grid (m X n) matrix. I used the g77 compiler and successfully created a dll file and it also loads successfully from R. But somehow the programs fails to run properly. (I do get the correct result when I compile the
2008 Nov 07
4
chi square table
Hi,
How do we get the value of a chi square as we usually look up on the
table on our text book?
i.e. Chi-square(0.01, df=8), the text book table gives 20.090
> dchisq(0.01, df=8)
[1] 1.036471e-08
> pchisq(0.01, df=8)
[1] 2.593772e-11
> qchisq(0.01, df=8)
[1] 1.646497
>
nono of them give me 20.090
Thanks,
cruz
2008 Jul 17
5
calculate differences - strange outcome
Dear List,
I ran into some trouble by calculating differences. For me it is
important that differences are either 0 or not.
So I don't understand the outcome of this calculation
865.56-(782.86+0+63.85+18.85+0)
[1] -1.136868e-13
I run R version 2.71 on WinXP
I could solve my problem by using
round()
but I would like to know the reason.
Maybe someone can help me?
Thanx
2008 Jan 15
2
Looking for simpler solution to probabilistic question
Hi
I have two processes which take with a certain probability (p1 and p2) x
number of years to complete (age1 and age2). As soon as thge first
process is completed, the second one begins. I want to calculate the
time it takes for the both processes to be completed.
I have the following script which gives me the answer, butI think there
must be a more elegant way of doing the calculations
2009 Mar 26
1
Conerned about Interfacing R with Fortran
I am reading the manual sections illustrating how to call a Fortran subroutine from R.
I feel uneasy at the explicit statement about ".Fortran" interface working with Fortran 77.
I would like to call a Fortran-90 subroutine from my R script. Is that supported at all ?
Thank you,
Maura
tutti i telefonini TIM!
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2008 Mar 04
2
Strange paste, string or package problem?
Hi
I came across this strange bug the other day, I'm not sure how to solve it
and I wonder if anyone can even replicate it.
Using OS Ubuntu 7.10
Step 1) Make an R package using the package.skeleton() command with
only these two functions:
error <- function(){
cmd <- paste(" -a ",1," -a ",1," -a ",1,
" -a ",1," -a
2009 May 04
4
Splitting a vector into equal groups
Hi All,
I have vector of length 52, say, x=sample(30,52,replace=T). I want to
sort x and split into five *nearly equal groups*. Note that the
observations are repeated in x so in case of a tie I want both the
observations to fall in same group.
This seems a very common task to do, but still I couldn't find an R
function to do this. Any help would be highly appreciated.
Regards
Utkarsh