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| bio | website | linkedin.com/pub/eric-brown/… |
|---|---|---|
| location | Evanston, Illinois | |
| age | ||
| visits | member for | 7 months |
| seen | 3 hours ago | |
| stats | profile views | 43 |
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Dec 9 |
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How to implement FittedModel like objects This is really awesome, and motivating. |
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Dec 5 |
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WinBUGS Interface I would really like to see some examples of Bayesian calculations with Markov chains! Do you have any? |
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Dec 5 |
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WinBUGS Interface I'm using RLink now to call R and run rjags and LaplacesDemon. It's easy to export the chains back into Mathematica. You might want to try RLink to call R2WinBUGS. Unfortunately, I don't have Windows or I would provide you with a starter template. |
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Dec 1 |
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Getting R textual output into Mathematica I'm getting close with REvaluate["capture.output(summary(airquality))"] // TableForm |
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Dec 1 |
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Accessing the Data of an RLink RDataFrame ...and with this answer, I just kicked my Emacs/StarterKit/org-mode/ESS/pgfSweave/ggplot2 "Frankenstein monster" to the curb. |
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Nov 29 |
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Installing CRAN Packages Your work is appreciated. Before 9, I was writing a lot of boilerplate code to write the R input to a text file, run R, "serialize," then bring in the results. I'm starting to get it figured out, and it is very powerful. Now it looks like things are standardized and so I can write toward that. |
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Nov 29 |
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Installing CRAN Packages It looks like it's possible to wget a binary package from a CRAN mirror right into the .../library directory. Now, I'm trying to figure out how to work with REvaluate itself. |
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Nov 29 |
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Using a different R version with RLink I would almost think that it would be easier under Mac/Linux. Meh. |
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Oct 16 |
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Why is NDSolve solving in term of two 1st order ODE slower than 2nd order? Yipper. Somewhere in the Mathematica documentation (I think Advanced NDSolve) there is a nice graphic for this. Method of Lines is for reducing PDEs -> set of ODES. But the resulting ODEs (and the ODE in the Mark's comment above) may be greater than 1st order, and then those are reduced to first order by techniques like substitution which result in as many 1st order equations as the order of the original nth order ODE. |
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Oct 15 |
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Why is NDSolve solving in term of two 1st order ODE slower than 2nd order? I'm interested in this, too. I thought Mathematica automatically decomposed the 2nd order ODE into a set of 1st order ODEs, and then those are solved. Maybe reducing the order by hand, taking into account certain simplifications that only you know, gives something faster than what Mathematica can deduce. On second read: Or maybe Mathematica finds a reduction that is better than what you have accomplished. |
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Oct 15 |
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Why is NDSolve solving in term of two 1st order ODE slower than 2nd order? Hi drN, this is an ODE. PDE would have something like: eqns,{var1,var2,var3}, {x,0,L}, {t,0,T} :-) |
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Oct 12 |
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1D Euler Equations @drN Not Sure what you mean. I was just trying different settings. Ack, yours is full of errors. = where there should be ==, {r,v,e} should be the variables, etc. Dale's code looks fine to me, though, don't know why it doesn't work. |
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Oct 10 |
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Problem with Estimating the parameters value of gamma distribution Sorry, folks, I did not see your comments before I made my post and my edits. |
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Oct 10 |
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Problem with Estimating the parameters value of gamma distribution @b.gatessucks Sorry, I did not see your comments. |
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Oct 9 |
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1D Euler Equations I hammered on this for a while, and got nowhere. BTW, I think in the r0[x_]:= its 0.125 (least of your worries) If you go through and make everything a fraction e.g. 1.4 -> 14/10 then it doesn't even crank, crashing out with a 1/0 ComplexInfinity error... |
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Oct 8 |
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Unexpected results from NDSolve LSODA rocks. It has some nice stiff/nonstiff switching capabilities that seem to "just work" for a lot of problems. It goes on land and sea. |
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Oct 8 |
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Unexpected results from NDSolve a) in your "Event" should it be c2[r,t] instead of c2[t,r]?b) When I add StepMonitor :> Print[c2[r,t]] it appears that r is not getting set, leading to a non-real number (rather than complex) Neither of these comments help with your problem, though. What was the original equation? Maybe that can be debugged and all this EventLocator stuff can be avoided. :-) |
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Oct 8 |
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Asymptotic Rate of Growth Are you asking for a generalized way of determining which term, e.g. x^3, x^2, x, or 1 grows fastest as x increases? |
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Oct 7 |
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Launching remote kernels - will it help RAM needs? Probably the best option--cheapest and most likely to work. :-) BTW, if you have found any of my several comments helpful, please click the little up arrow. :-> |
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Oct 7 |
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Launching remote kernels - will it help RAM needs? Not sure what you are looking for. See DistributedContexts. It is an option of ParallelTable and friends. This won't help your original NDSolve problem because it is a problem that is not easily parallelized. But if you could solve it for one problem, then you might imagine sending different initial values to different nodes and having each of them run different NDSolves. a) Ask your advisor for $$$ for equipment/software b) pay yourself c) change software d) simplify model. Sorry, no free lunch :-( |
