similar to: mysql connection problems

Hi, I have a many-to-many relationship between two tables, questions and answers. My MySQL schema for the link table creates a primary key from the two fields to prevent duplicate records. When I add the same answer to the same question more than once, rails attempts to create a duplicate record and explodes with a MySQL error: MysqlError: Duplicate entry ''3-3'' for key 1:

Dear list, I would like to produce a matrix of plots, where par() is reset after each plot (see below [simplified] example). When I use layout() to do so, I seem to also reset the layout. I have not been able to figure out how to prevent this from happening. Any help is greatly appreciated! Janke Example code: #Desired result is a layout of 2 plots: one red and one black layout(matrix(1:2,

At the risk of ridicule for my deficient linear algebra skills, I ask for help using the solve.QP function to do portfolio optimization. I am trying to following a textbook example and need help converting the problem into the format required by solve.QP. Below is my sample code if anyone is willing to go through it. This problem will not solve because it is not set up properly. I hope I

Hi everybody, I'm using Windows XP Prof, R 2.5.1 and a Pentium 4 Processor. Now, I want to solve a quadratic optimization program (Portfolio Selection) with the quadprog package I want to minimize (\omega'%*%\Sigma%*%\omega) Subject to (1) \iota' %*% \omega = 1 (full investment) (2) R'%*%\omega = \mu (predefined expectation value) (3) \omega \ge 0 (no short sales). Where

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

Hi All, I've hit a problem using nls. I think it may be a restriction in the applicability of nls and I may have found a fix, but I've been wrong before. This example is simplified to the essentials. My real application is much more complicated. Take a function of matrix 'x' with additional arguments: matrix 'aMat' whose values are _not_ to be determined by nls vector

On 7/9/07, Arnaud QUETTE <Arnaud.QUETTE at mgeups.com> wrote: > > My UPS is a: Upsonic CXR1000 (made in Oz, probably rebranded > monitoring) > > Driver: Megatec > > > > Works perfectly! [snip] > I'll add your model to the supported ones once Carlos has validated > everything is fine. I can do that.

Hi I'm having problems getting the "factorized" argument in solve.QP (part of the quadprog library) to work as expected. The helpfile states that when the factorized argument is set to TRUE, then the function requires the inverse of a square-root factor of the Hessian instead of the Hessian itself. That is, when factorized=TRUE, the Dmat argument should be a matrix R^(-1), such

Dear list members, I am trying to get information on how to fit a linear regression with constrained parameters. Specifically, I have 8 predictors , their coeffiecients should all be non-negative and add up to 1. I understand it is a quadratic programming problem but I have no experience in the subject. I searched the archives but the results were inconclusive. Could someone provide suggestions

Hi , Help is needed to restore mysql data This is the the setup. 2 Servers running on CentOS. one server has both apache an mysql. the other server only has mysql database. This server has about 12000 records in the database. Last week, It had about 6000 records. then, Someone has backed up these 6000 records to the web server. Now , We need to backup all 12000 records to the webserver.

Hi All, I have the following adjacency matrix for a directed graph: [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [1,] 0 0 0 0 0 0 0 0 [2,] 0 0 0 0 0 0 0 0 [3,] 1 0 0 0 0 0 0 0 [4,] 0 0 1 0 0 0 0 0 [5,] 0 0 1 0 0 0 0 0 [6,] 1 1 0 0 0 0 0 0 [7,] 0 0

Dear all, I need to maximize the v: v= D' W D D is a column vector ( n , 1) W is a given matrix (n, n) subject to: sum D= 1 (BTW, n is less than 300) I´ve tried to use maxBFGS, as follows: ##################################### objectiveFunction<-function(x) { return(t(D)%*%W%*%D) } Amat<-diag(nrow(D)) Amat<-rbind((rep(-1, nrow(D))), Amat) bvec<-matrix( c(0), nrow(D)+1,

I'm having difficulty figuring out how to implement the following set of constraints in Quadprog: 1). x1+x2+x3+x4=a1 2). x1+x2+x5+x6=a2 3). x1+x3+x5+x7=a3 4). x1+x2=b1 5). x1+x3=b2 6). x1+x5=b3 for the problem: MIN (x1-c1)2+(x2-c2)2+...+(x8-c8)2. As far a I understand, "solve.QP(Dmat, dvec, Amat, bvec, meq=0, factorized=FALSE)" reads contraints using an element-by-element

Hey all, This example of working code: @a = @b.where(:a_group_id.ne => nil).collect { |b| b.a_group } doesn''t make too much sense to me. For one, I am not sure what that "ne" is doing there. Is this a postgresql thing? Second, it looks like we are collecting active record objects where the a_group_id is null, collecting them in an array and then invoking the a_group

I''ve got my applications running on a server that backs up every hour using MySQLdump. My goal is to take this ''dump'' and re-import it into my desktop computer using MySQLAdministrator. I go through the procedure of restoring this ''backup.sql'' file and it grinds for some time as though something is happening...and then nothing?? There are no error

Hi list: This is my first time to post my question on the list. Thanks for your help. I am solving a quadratic programming using R. Here is my question: w = arg min 0.5*w'Mw - w'N s. t. sum(w) = 1; w>0 note: w is weight vector, each w_i must >=0, and the sum of w =1. Here is my R code: A <-matrix(c(2.26,1.26,1.12,1.12,2.27,1.13,1.12,1.13,2.2),3,3); B <-

Hello, I am switching from SPSS-Windows to R-Linux. My university is very SPSS-oriented so maybe that's the cause of my problems. I am a beginner in R and my assignments are SPSS-oriented, so I hope I don't annoy anyone with my questions... Right now I've got 2 problems: -I have to evaluate discriminant functions I have calculated with lda(MASS). I can't find a measure that

Hi, I'm using the package quadprog to solve the following quadratic programming problem. I want to minimize the function (b_1-b_2)^2+(b_3-b_4)^2 by the following constraints b_i, i=1,...,4: b_1+b_3=1 b_2+b_4=1 0.1<=b_1<=0.2 0.2<=b_2<=0.4 0.8<=b_3<=0.9 0.6<=b_4<=0.8 In my opinion the solution should be b_1=b_2=0.2 und b_3=b_4=0.8. Unfortunately R doesn't find

Hi! I''ve just installed xen from source (had a prebuilt install before). Just made ''make world'' and ''make install'' and tried to reuse an old domU. But while booting an fsck error appears. ---------------------------- fsck.ext3: No such file or directory while trying to open /dev/hda6 /dev/hda6: The superblock could not be read or does not describe a

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