search for: conjugate

Hi, All: Is there a simple way to detect complex conjugates in the roots returned by 'polyroot'? The obvious comparison of each root with the complex conjugate of the next sometimes produces roundoff error, and I don't know how to bound its magnitude: (tst <- polyroot(c(1, -.6, .4))) tst[-1]-Conj(tst[-2]) [1] 3.108624e-15+2.22045e-16i...

Is there a function in R that returns the complex conjugate of a matrix (a la 'CONJ' in IDL or 'Conjugate' in Mathmatica)?

...rvations, but without an implementation of a transformation that can handle very small values, my sampling algorithms would not work. This is an attempt to use some sampling algorithms for Bayesian parameter estimation. I do not want to resort to conjugacy, since I am developing this to handle non conjugate scenarios, I just wanted to test it on a conjugate scenario, but I've quickly realized that I'm in trouble due to likelihood reaching 0 quickly. Your feedback would be appreciated. It makes me wonder how JAGS/BUGS handles this problem Best regards Seref [[alternative HTML version delete...

Dear list, I am using optim() function to MLE ~55 parameters, but it is very slow to converge (~ 25 min), whereas I can do the same in ~1 sec. using ADMB, and ~10 sec using MS EXCEL Solver. Are there any tricks to speed up? Are there better optimization functions? Thanks Toshihide "Hamachan" Hamazaki, $B_@:j=S=((JPhD Alaska Department of Fish and Game:

Hi, Man page for 'convolve' says: conj: logical; if 'TRUE', take the complex _conjugate_ before back-transforming (default, and used for usual convolution). The complex conjugate of 'x', of 'y', of both? In fact it seems that it takes the complex conjugate of 'y' only which is OK but might be worth mentioning because (1) conj=TRUE is the default and...

Hello everybody When one is working with complex matrices, "transpose" very nearly always means *Hermitian* transpose, that is, A[i,j] <- Conj(A[j,i]). One often writes A^* for the Hermitian transpose. I have only once seen a "real-life" case where transposition does not occur simultaneously with complex conjugation. And I'm not 100% sure that that wasn't a

Hi Does anyone know of any R coding/functions for MCMC approaches? I am currently using BUGS but I wonder if the bazaar has produced anything? I think I am pushing BUGS to it's limit and possibly past it at the moment. John -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send

Krzysztof Parzyszek via llvm-dev <llvm-dev at lists.llvm.org> writes: > Vectorization must know the data layout: whether we have vectors (r1, > i1, r2, i2...) or (r1, r2, ...), (i1, i2, ...). These two approaches > are not compatible. If you have vector registers that can hold 8 > floats, with the first approach you can load 4 complex numbers in a > single instruction, then

Good afternoon/morning readers. This is the first time I am trying to run some Bayesian computation in R, and am experiencing a few problems. I am working on a Poisson model for cancer rates which has a conjugate Gamma prior. 1) The first question is precisely how I work out the parameters. #Suppose I assign values to theta with *seq()* *theta<-seq(0,1,len=500)* #Then I try out the parameters that seem to fit with a certain prior idea on theta (see next) *a=182* *b=3530* *gaprior<-dgamma(theta,a,b)...

..."ac-bd" together, not >>> what type a,b,c,d are. >> >> Can you give some examples of non-FP types where a higher-level representation would be useful? > > Hexagon has instructions to do complex multiplication on pairs i16 x i16 (plus variants like accumulate, conjugate, etc.). How difficult are these to pattern match on scalar code? -Chris

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Hi. I'm trying to use Wine 0.9.12 under Ubuntu 6.06 to run "Verbix7.3" (www.verbix.com): when it all seems to be done, when I select the verb to be viewed, this doesn't happen, and I see the following error in a MsgBox: Fatal error in Verbix: Unexpected error occured at 00000000 Errormessage was: "Method 'tenses' not supported by automation object" Error

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...ng to fit point process conditional intensity models via maximum likelihood. However, I noticed that the gradient of the objective function must be supplied for all but the Nelder-Mead method. I was wondering why this was because optim() itself does not require a gradient function for the BFGS or Conjugate Gradient methods. Thanks, -roger _______________________________ UCLA Department of Statistics rpeng@stat.ucla.edu http://www.stat.ucla.edu/~rpeng

...p the n11 entry and n22 entry of nvec, I received totally different Bayes factor: > > HWETriangBF2(nvec=c(2,10,88)) [1] 5.710153 > In my understanding, defining the genotype frequency as n11 or n22 are arbitrary. So I was expecting the same value of Bayes factor. This is the case for conjugate Dirichlet prior: >DirichNormHWE(nvec=c(88,10,2), c(1,1))/DirichNormSat(nvec=c(88,10,2), c(1,1,1)) [1] 1.542047 >DirichNormHWE(nvec=c(2,10,88), c(1,1))/DirichNormSat(nvec=c(2,10,88), c(1,1,1)) [1] 1.542047 Could you explain why the HWETriangBF2 is returining completely different values of Bay...

Does anyone know of contributions to R for solving sparse linear systems? In particular for spatial stats I am interested in solving large positive definite symmetric systems. Thanks in advance, Doug ----------------------------------------------------------------------------- Doug Nychka, Geophysical Statistics Project Email: nychka at ucar.edu National Center for Atmospheric

...ere are N i.i.d zero-mean complex gaussian random variables(RVs),as w(i),0<=i<N} with known variance,from which one can generate another N RVs,as R(0)=sum over i {w(i)*w'(i)} R(1)=sum over i {w(i+1)*w'(i)} ... up to R(N-1)= w(N-1)w'(i) where w'(i) is the complex conjugate of w(i). (from viewpoint of signal processing, R(i) are serial correlation of time series w(i)) If one defines a new random variable using {R(k)} as Z=a(0)R(0)+a(1)|R(1)|+... a(N-1)|R(N-1)|, with {a(k)} are known and |.| is modulus operation.It's a decision statistic encountered in my work....

...n implementation of the spectral projected gradient method for the optimization of (smooth) nonlinear objective functions, subject to simple constraints that can be defined as a projection mapping. This function, spg(), is suited for large-scale optimization. It generally performs better than the conjugate-gradient methods in "optim", and complements the "low-memory BFGS" method for constraints that can be defined by the user as projection mapping. Best regards, Ravi. ---------------------------------------------------------------------------- ------- Ravi Varadhan, Ph.D....

Hello all, I am new to the list, but I have been using ferret for a little bit already. I would first like to thank Dave for all his work on ferret. I had a few questions that I haven''t been able to figure out after messing around with ferret and going through the documentation. StemFilter ------ I am trying to improve the quality of my searches in context of the content of my

...d come along in recent years? Alternatively, are there any really good companion textbooks / lab manuals to accompany standard texts? Thanks in advance, Richard -- I think back to the halcyon dates of my youth, when indeterminate Hessians had something to do with the Revolutionary War, where conjugate priors were monks who had broken their vows, and the expression (X'X)^-1(X'Y) was greek Those were simpler times