similar to: Constrained fits: y~a+b*x-c*x^2, with a,b,c >=0

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. [[alternative HTML version deleted]]
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 [[alternative HTML version deleted]]
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 [[alternative HTML version deleted]]
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! [[alternative HTML version deleted]]
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